keytool
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Synopsis
keytool
[ commands ]
The keytool
command interface has changed in Java SE 6. See the Changes
Section for a detailed description. Note that previously
defined commands are still supported.
add an example, a script, a trick and tips
examples
Suppose you want to create a keystore for managing your
public/private key pair and certificates from entities you trust.
Generating Your Key Pair
The first thing you need to do is create a keystore and generate
the key pair. You could use a command such as the following:
keytool -genkeypair -dname "cn=Mark Jones, ou=Java, o=Oracle,
c=US"
-alias business -keypass <new password for private
key> -keystore /working/mykeystore
-storepass <new password for keystore>
-validity 180
(Please note: This must be typed as a single line. Multiple lines
are used in the examples just for legibility purposes.)
This command creates the keystore named "mykeystore" in the
"working" directory (assuming it doesn’t already exist), and
assigns it the password specified by <new password for
keystore>. It generates a public/private key pair for the
entity whose "distinguished name" has a common name of "Mark
Jones", organizational unit of "Java", organization of "Oracle"
and two-letter country code of "US". It uses the default "DSA"
key generation algorithm to create the keys, both 1024 bits long.
It creates a self-signed certificate (using the default
"SHA1withDSA" signature algorithm) that includes the public key
and the distinguished name information. This certificate will be
valid for 180 days, and is associated with the private key in a
keystore entry referred to by the alias "business". The private
key is assigned the password specified by <new password for
private key>.
The command could be significantly shorter if option defaults
were accepted. As a matter of fact, no options are required;
defaults are used for unspecified options that have default
values, and you are prompted for any required values. Thus, you
could simply have the following:
keytool -genkeypair
In this case, a keystore entry with alias "mykey" is created,
with a newly-generated key pair and a certificate that is valid
for 90 days. This entry is placed in the keystore named
".keystore" in your home directory. (The keystore is created if
it doesn’t already exist.) You will be prompted for the
distinguished name information, the keystore password, and the
private key password.
The rest of the examples assume you executed the
-genkeypair command without options specified, and that
you responded to the prompts with values equal to those given in
the first -genkeypair command, above (for example, a
distinguished name of "cn=Mark Jones, ou=Java, o=Oracle, c=US").
Requesting a Signed Certificate from a Certification
Authority
So far all we’ve got is a self-signed certificate. A certificate
is more likely to be trusted by others if it is signed by a
Certification Authority (CA). To get such a signature, you first
generate a Certificate Signing Request (CSR), via the following:
keytool -certreq -file MarkJ.csr
This creates a CSR (for the entity identified by the default
alias "mykey") and puts the request in the file named
"MarkJ.csr". Submit this file to a CA, such as VeriSign, Inc. The
CA will authenticate you, the requestor (usually off-line), and
then will return a certificate, signed by them, authenticating
your public key. (In some cases, they will actually return a
chain of certificates, each one authenticating the public key of
the signer of the previous certificate in the chain.)
Importing a Certificate for the CA
You need to replace your self-signed certificate with a
certificate chain, where each certificate in the chain
authenticates the public key of the signer of the previous
certificate in the chain, up to a "root" CA.
Before you import the certificate reply from a CA, you need one
or more "trusted certificates" in your keystore or in the
cacerts keystore file (which is described in importcert
command):
o
If the certificate reply is a certificate chain, you just need
the top certificate of the chain (that is, the "root" CA
certificate authenticating that CA’s public key).
o
If the certificate reply is a single certificate, you need a
certificate for the issuing CA (the one that signed it), and if
that certificate is not self-signed, you need a certificate for
its signer, and so on, up to a self-signed "root" CA certificate.
The "cacerts" keystore file ships with several VeriSign root CA
certificates, so you probably won’t need to import a VeriSign
certificate as a trusted certificate in your keystore. But if you
request a signed certificate from a different CA, and a
certificate authenticating that CA’s public key hasn’t been added
to "cacerts", you will need to import a certificate from the CA
as a "trusted certificate".
A certificate from a CA is usually either self-signed, or signed
by another CA (in which case you also need a certificate
authenticating that CA’s public key). Suppose company ABC, Inc.,
is a CA, and you obtain a file named "ABCCA.cer" that is
purportedly a self-signed certificate from ABC, authenticating
that CA’s public key.
Be very careful to ensure the certificate is valid prior to
importing it as a "trusted" certificate! View it first (using the
keytool -printcert command, or the keytool
-importcert command without the -noprompt option),
and make sure that the displayed certificate fingerp
source
keytool -delete -alias screencastAlias
source
keytool -list -v -keystore keys/sample.keystore
source
keytool -genkey -alias copad -validity 365
source
keytool -list -keystore $1
-storepass $2 -v
source
keytool -genkey -keyalg RSA -keystore server.keystore
-validity 3650
source
keytool -list -keystore server.keystore -storepass
nika21
description
keytool
is a key and certificate management utility. It allows users
to administer their own public/private key pairs and
associated certificates for use in self-authentication
(where the user authenticates himself/herself to other
users/services) or data integrity and authentication
services, using digital signatures. It also allows users to
cache the public keys (in the form of certificates) of their
communicating peers.
A
certificate is a digitally signed statement from one
entity (person, company, etc.), saying that the public key
(and some other information) of some other entity has a
particular value. (See Certificates.) When data is digitally
signed, the signature can be verified to check the data
integrity and authenticity. Integrity means that the
data has not been modified or tampered with, and
authenticity means the data indeed comes from whoever
claims to have created and signed it.
keytool
also enables users to administer secret keys used in
symmetric encryption/decryption (e.g. DES).
keytool
stores the keys and certificates in a keystore.
changes
The command interface for keytool changed in Java SE 6.
keytool no longer displays password input when entered by
users. Since password input can no longer be viewed when entered,
users will be prompted to re-enter passwords any time a password
is being set or changed (for example, when setting the initial
keystore password, or when changing a key password).
Some commands have simply been renamed, and other commands deemed
obsolete are no longer listed in this document. All previous
commands (both renamed and obsolete) are still supported in this
release and will continue to be supported in future releases. The
following summarizes all of the changes made to the keytool
command interface:
Renamed commands:
o
-export, renamed to -exportcert
o
-genkey, renamed to -genkeypair
o
-import, renamed to -importcert
Commands deemed obsolete and no longer documented:
o
-keyclone @
http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/keytool.html#keycloneCmd
o
-identitydb @
http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/keytool.html#identitydbCmd
o
-selfcert @
http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/keytool.html#selfcertCmd
commands
Creating or Adding Data to the Keystore
-gencert {-rfc} {-infile infile} {-outfile outfile} {-alias
alias}
{-sigalg sigalg} {-dname dname} {-startdate startdate {-ext
ext}*
{-validity valDays} [-keypass keypass] {-keystore keystore}
[-storepass storepass] {-storetype storetype} {-providername
provider_name} {-providerClass provider_class_name
{-providerArg
provider_arg}} {-v} {-protected} {-Jjavaoption}
Generates a certificate as a response to a certificate request
file (which can be created by the keytool -certreq
command). The command reads the request from infile (if
omitted, from the standard input), signs it using alias’s private
key, and output the X.509 certificate into outfile (if
omitted, to the standard output). If -rfc is specified,
output format is BASE64-encoded PEM; otherwise, a binary DER is
created.
sigalg specifies the algorithm that should be used to sign
the certificate. startdate is the start time/date that the
certificate is valid. valDays tells the number of days for
which the certificate should be considered valid.
If dname is provided, it’s used as the subject of the
generated certificate. Otherwise, the one from the certificate
request is used.
ext shows what X.509 extensions will be embedded in the
certificate. Read Common Options for the grammar of -ext.
The -gencert command enables you to create certificate
chains. The following example creates a certificate, e1,
that contains three certificates in its certificate chain.
The following commands creates four key pairs named ca,
ca1, ca2, and e1:
keytool -alias ca -dname CN=CA -genkeypair
keytool -alias ca1 -dname CN=CA -genkeypair
keytool -alias ca2 -dname CN=CA -genkeypair
keytool -alias e1 -dname CN=E1 -genkeypair
The following two commands create a chain of signed certificates;
ca signs ca1 and ca1 signs ca2, all of which are
self-issued:
keytool -alias ca1 -certreq | keytool -alias ca -gencert -ext
san=dns:ca1 | keytool -alias ca1 -importcert
keytool -alias ca2 -certreq | $KT -alias ca1 -gencert -ext
san=dns:ca2 | $KT -alias ca2 -importcert
The following command creates the certificate e1 and
stores it in the file e1.cert, which is signed by
ca2. As a result, e1 should contain ca,
ca1, and ca2 in its certificate chain:
keytool -alias e1 -certreq | keytool -alias ca2 -gencert >
e1.cert
-genkeypair {-alias alias} {-keyalg keyalg} {-keysize
keysize}
{-sigalg sigalg} [-dname dname] [-keypass keypass]
{-startdate
value} {-ext ext}* {-validity valDays} {-storetype storetype}
{-keystore keystore} [-storepass storepass] {-providerClass
provider_class_name {-providerArg provider_arg}} {-v}
{-protected}
{-Jjavaoption}
Generates a key pair (a public key and associated private key).
Wraps the public key into an X.509 v3 self-signed certificate,
which is stored as a single-element certificate chain. This
certificate chain and the private key are stored in a new
keystore entry identified by alias.
keyalg specifies the algorithm to be used to generate the
key pair, and keysize specifies the size of each key to be
generated. sigalg specifies the algorithm that should be
used to sign the self-signed certificate; this algorithm must be
compatible with keyalg.
dname specifies the X.500 Distinguished Name to be
associated with alias, and is used as the issuer
and subject fields in the self-signed certificate. If no
distinguished name is provided at the command line, the user will
be prompted for one.
keypass is a password used to protect the private key of
the generated key pair. If no password is provided, the user is
prompted for it. If you press RETURN at the prompt, the key
password is set to the same password as that used for the
keystore. keypass must be at least 6 characters long.
startdate specifies the issue time of the certificate,
also known as the "Not Before" value of the X.509 certificate’s
Validity field.
The option value can be set in one of these two forms:
1.
([+-]nnn[ymdHMS])+
2.
[yyyy/mm/dd] [HH:MM:SS]
With the first form, the issue time is shifted by the specified
value from the current time. The value is a concatenation of a
sequence of sub values. Inside each sub value, the plus sign
("+") means shifting forward, and the minus sign ("-") means
shifting backward. The time to be shifted is nnn units of
years, months, days, hours, minutes, or seconds (denoted by a
single character of "y", "m", "d", "H", "M", or "S"
respectively). The exact value of the issue time is calculated
using the java.util.GregorianCalendar.add(int field, int
amount) method on each sub value, from left to right. For
example, by specifying "-startdate -1y+1m-1d", the issue
time will be:
Calendar c = new GregorianCalendar();
c.add(Calendar.YEAR, -1);
c.add(Calendar.MONTH, 1);
c.add(Calendar.DATE, -1);
return c.getTime()
With the second form, the user sets the exact issue time in two
parts, year/month/day and hour:minute:second (using the local
time zone). The user may provide only one part, which means the
other part is the same as the current date (or time). User must
provide the exact number of digits as shown in the format
definition (padding with 0 if shorter). When both the date and
time are provided, there is one (and only one) space character
between the two parts. The hour should always be provided in 24
hour format.
When the option is not provided, the start date is the current
time. The option can be provided at most once.
valDays specifies the number of days (starting at the date
specified by -startdate, or the current date if
-startdate is not specified) for which the certificate
should be considered valid.
This command was named -genkey in previous releases. This
old name is still supported in this release and will be supported
in future releases, but for clarity the new name,
-genkeypair, is preferred going forward.
-genseckey {-alias alias} {-keyalg keyalg} {-keysize keysize}
[-keypass keypass] {-storetype storetype} {-keystore
keystore}
[-storepass storepass] {-providerClass provider_class_name
{-providerArg provider_arg}} {-v} {-protected} {-Jjavaoption}
Generates a secret key and stores it in a new
KeyStore.SecretKeyEntry identified by alias.
keyalg specifies the algorithm to be used to generate the
secret key, and keysize specifies the size of the key to
be generated. keypass is a password used to protect the
secret key. If no password is provided, the user is prompted for
it. If you press RETURN at the prompt, the key password is set to
the same password as that used for the keystore. keypass
must be at least 6 characters long.
-importcert {-alias alias} {-file cert_file} [-keypass
keypass]
{-noprompt} {-trustcacerts} {-storetype storetype} {-keystore
keystore} [-storepass storepass] {-providerName
provider_name}
{-providerClass provider_class_name {-providerArg
provider_arg}}
{-v} {-protected} {-Jjavaoption}
Reads the certificate or certificate chain (where the latter is
supplied in a PKCS#7 formatted reply or a sequence of X.509
certificates) from the file cert_file, and stores it in
the keystore entry identified by alias. If no file is
given, the certificate or certificate chain is read from stdin.
keytool can import X.509 v1, v2, and v3 certificates, and
PKCS#7 formatted certificate chains consisting of certificates of
that type. The data to be imported must be provided either in
binary encoding format, or in printable encoding format (also
known as Base64 encoding) as defined by the Internet RFC 1421
standard. In the latter case, the encoding must be bounded at the
beginning by a string that starts with "-----BEGIN", and bounded
at the end by a string that starts with "-----END".
You import a certificate for two reasons:
1.
to add it to the list of trusted certificates, or
2.
to import a certificate reply received from a CA as the result of
submitting a Certificate Signing Request (see the -certreq
command) to that CA.
Which type of import is intended is indicated by the value of the
-alias option:
1.
If the alias does not point to a key entry, then
keytool assumes you are adding a trusted certificate
entry. In this case, the alias should not already exist in the
keystore. If the alias does already exist, then keytool
outputs an error, since there is already a trusted certificate
for that alias, and does not import the certificate.
2.
If the alias points to a key entry, then keytool
assumes you are importing a certificate reply.
Importing a New Trusted Certificate
Before adding the certificate to the keystore, keytool
tries to verify it by attempting to construct a chain of trust
from that certificate to a self-signed certificate (belonging to
a root CA), using trusted certificates that are already available
in the keystore.
If the -trustcacerts option has been specified, additional
certificates are considered for the chain of trust, namely the
certificates in a file named "cacerts".
If keytool fails to establish a trust path from the
certificate to be imported up to a self-signed certificate
(either from the keystore or the "cacerts" file), the certificate
information is printed out, and the user is prompted to verify
it, e.g., by comparing the displayed certificate fingerprints
with the fingerprints obtained from some other (trusted) source
of information, which might be the certificate owner
himself/herself. Be very careful to ensure the certificate is
valid prior to importing it as a "trusted" certificate! -- see
WARNING Regarding Importing Trusted Certificates. The user then
has the option of aborting the import operation. If the
-noprompt option is given, however, there will be no
interaction with the user. Importing a Certificate Reply
When importing a certificate reply, the certificate reply is
validated using trusted certificates from the keystore, and
optionally using the certificates configured in the "cacerts"
keystore file (if the -trustcacerts option was specified).
The methods of determining whether the certificate reply is
trusted are described in the following:
o
If the reply is a single X.509 certificate, keytool
attempts to establish a trust chain, starting at the certificate
reply and ending at a self-signed certificate (belonging to a
root CA). The certificate reply and the hierarchy of certificates
used to authenticate the certificate reply form the new
certificate chain of alias. If a trust chain cannot be
established, the certificate reply is not imported. In this case,
keytool does not print out the certificate and prompt the
user to verify it, because it is very hard (if not impossible)
for a user to determine the authenticity of the certificate
reply.
o
If the reply is a PKCS#7 formatted certificate chain or a
sequence of X.509 certificates, the chain is ordered with the
user certificate first followed by zero or more CA certificates.
If the chain ends with a self-signed root CA certificate and
-trustcacerts option was specified, keytool will
attempt to match it with any of the trusted certificates in the
keystore or the "cacerts" keystore file. If the chain does not
end with a self-signed root CA certificate and the
-trustcacerts option was specified, keytool will
try to find one from the trusted certificates in the keystore or
the "cacerts" keystore file and add it to the end of the chain.
If the certificate is not found and -noprompt option is
not specified, the information of the last certificate in the
chain is printed out, and the user is prompted to verify it.
If the public key in the certificate reply matches the user’s
public key already stored with under alias, the old
certificate chain is replaced with the new certificate chain in
the reply. The old chain can only be replaced if a valid
keypass, the password used to protect the private key of
the entry, is supplied. If no password is provided, and the
private key password is different from the keystore password, the
user is prompted for it.
This command was named -import in previous releases. This
old name is still supported in this release and will be supported
in future releases, but for clarify the new name,
-importcert, is preferred going forward.
-importkeystore -srckeystore srckeystore -destkeystore
destkeystore
{-srcstoretype srcstoretype} {-deststoretype deststoretype}
[-srcstorepass srcstorepass] [-deststorepass deststorepass]
{-srcprotected} {-destprotected} {-srcalias srcalias
{-destalias
destalias} [-srckeypass srckeypass] [-destkeypass destkeypass]
}
{-noprompt} {-srcProviderName src_provider_name}
{-destProviderName
dest_provider_name} {-providerClass provider_class_name
{-providerArg provider_arg}} {-v} {-protected} {-Jjavaoption}
Imports a single entry or all entries from a source keystore to a
destination keystore.
When the srcalias option is provided, the command imports
the single entry identified by the alias to the destination
keystore. If a destination alias is not provided with
destalias, then srcalias is used as the destination
alias. If the source entry is protected by a password,
srckeypass will be used to recover the entry. If
srckeypass is not provided, then keytool will
attempt to use srcstorepass to recover the entry. If
srcstorepass is either not provided or is incorrect, the
user will be prompted for a password. The destination entry will
be protected using destkeypass. If destkeypass is
not provided, the destination entry will be protected with the
source entry password.
If the srcalias option is not provided, then all entries
in the source keystore are imported into the destination
keystore. Each destination entry will be stored under the alias
from the source entry. If the source entry is protected by a
password, srcstorepass will be used to recover the entry.
If srcstorepass is either not provided or is incorrect,
the user will be prompted for a password. If a source keystore
entry type is not supported in the destination keystore, or if an
error occurs while storing an entry into the destination
keystore, the user will be prompted whether to skip the entry and
continue, or to quit. The destination entry will be protected
with the source entry password.
If the destination alias already exists in the destination
keystore, the user is prompted to either overwrite the entry, or
to create a new entry under a different alias name.
Note that if -noprompt is provided, the user will not be
prompted for a new destination alias. Existing entries will
automatically be overwritten with the destination alias name.
Finally, entries that can not be imported are automatically
skipped and a warning is output.
-printcertreq {-file file}
Prints the content of a PKCS #10 format certificate request,
which can be generated by the keytool -certreq command. The
command reads the request from file; if omitted, from the
standard input.
Exporting Data
-certreq {-alias alias} {-dname dname} {-sigalg sigalg}
{-file
certreq_file} [-keypass keypass] {-storetype storetype}
{-keystore
keystore} [-storepass storepass] {-providerName
provider_name}
{-providerClass provider_class_name {-providerArg
provider_arg}}
{-v} {-protected} {-Jjavaoption}
Generates a Certificate Signing Request (CSR), using the PKCS#10
format.
A CSR is intended to be sent to a certificate authority (CA). The
CA will authenticate the certificate requestor (usually off-line)
and will return a certificate or certificate chain, used to
replace the existing certificate chain (which initially consists
of a self-signed certificate) in the keystore.
The private key associated with alias is used to create
the PKCS#10 certificate request. In order to access the private
key, the appropriate password must be provided, since private
keys are protected in the keystore with a password. If
keypass is not provided at the command line, and is
different from the password used to protect the integrity of the
keystore, the user is prompted for it. If dname is provided, it’s
used as the subject in the CSR. Otherwise, the X.500
Distinguished Name associated with alias is used.
sigalg specifies the algorithm that should be used to sign
the CSR.
The CSR is stored in the file certreq_file. If no file is
given, the CSR is output to stdout.
Use the importcert command to import the response from the
CA.
-exportcert {-alias alias} {-file cert_file} {-storetype
storetype}
{-keystore keystore} [-storepass storepass] {-providerName
provider_name} {-providerClass provider_class_name
{-providerArg
provider_arg}} {-rfc} {-v} {-protected} {-Jjavaoption}
Reads (from the keystore) the certificate associated with
alias, and stores it in the file cert_file.
If no file is given, the certificate is output to stdout.
The certificate is by default output in binary encoding, but will
instead be output in the printable encoding format, as defined by
the Internet RFC 1421 standard, if the -rfc option is
specified.
If alias refers to a trusted certificate, that certificate
is output. Otherwise, alias refers to a key entry with an
associated certificate chain. In that case, the first certificate
in the chain is returned. This certificate authenticates the
public key of the entity addressed by alias.
This command was named -export in previous releases. This
old name is still supported in this release and will be supported
in future releases, but for clarify the new name,
-exportcert, is preferred going forward.
Displaying Data
-list {-alias alias} {-storetype storetype} {-keystore
keystore}
[-storepass storepass] {-providerName provider_name}
{-providerClass
provider_class_name {-providerArg provider_arg}} {-v | -rfc}
{-protected} {-Jjavaoption}
Prints (to stdout) the contents of the keystore entry identified
by alias. If no alias is specified, the contents of the
entire keystore are printed.
This command by default prints the SHA1 fingerprint of a
certificate. If the -v option is specified, the
certificate is printed in human-readable format, with additional
information such as the owner, issuer, serial number, and any
extensions. If the -rfc option is specified, certificate
contents are printed using the printable encoding format, as
defined by the Internet RFC 1421 standard
You cannot specify both -v and -rfc.
-printcert {-file cert_file | -sslserver host[:port]}
{-jarfile
JAR_file {-rfc} {-v} {-Jjavaoption}
Reads the certificate from the file cert_file, the SSL
server located at host:port, or the signed JAR file
JAR_file (with the option -jarfile and prints its
contents in a human-readable format. When no port is specified,
the standard HTTPS port 443 is assumed. Note that
-sslserver and -file options cannot be provided at
the same time. Otherwise, an error is reported. If neither option
is given, the certificate is read from stdin.
If -rfc is specified, keytool prints the certificate in
PEM mode as defined by the Internet RFC 1421 standard.
If the certificate is read from a file or stdin, it may be either
binary encoded or in printable encoding format, as defined by the
Internet RFC 1421 standard
If the SSL server is behind a firewall,
-J-Dhttps.proxyHost=proxyhost and
-J-Dhttps.proxyPort=proxyport can be specified on the
command line for proxy tunneling. See the JSSE Reference
Guide @
http://docs.oracle.com/javase/7/docs/technotes/guides/security/jsse/JSSERefGuide.html
for more information.
Note: This option can be used independently of a
keystore.
-printcrl -file crl_ {-v}
Reads the certificate revocation list (CRL) from the file
crl_file.
A Certificate Revocation List (CRL) is a list of digital
certificates which have been revoked by the Certificate Authority
(CA) that issued them. The CA generates crl_file.
Note: This option can be used independently of a keystore.
Managing the Keystore
-storepasswd [-new new_storepass] {-storetype storetype}
{-keystore
keystore} [-storepass storepass] {-providerName
provider_name}
{-providerClass provider_class_name {-providerArg
provider_arg}}
{-v} {-Jjavaoption}
Changes the password used to protect the integrity of the
keystore contents. The new password is new_storepass,
which must be at least 6 characters long.
-keypasswd {-alias alias} [-keypass old_keypass] [-new
new_keypass]
{-storetype storetype} {-keystore keystore} [-storepass
storepass]
{-providerName provider_name} {-providerClass
provider_class_name
{-providerArg provider_arg}} {-v} {-Jjavaoption}
Changes the password under which the private/secret key
identified by alias is protected, from old_keypass
to new_keypass, which must be at least 6 characters long.
If the -keypass option is not provided at the command
line, and the key password is different from the keystore
password, the user is prompted for it.
If the -new option is not provided at the command line,
the user is prompted for it.
-delete [-alias alias] {-storetype storetype} {-keystore
keystore}
[-storepass storepass] {-providerName provider_name}
{-providerClass
provider_class_name {-providerArg provider_arg}} {-v}
{-protected}
{-Jjavaoption}
Deletes from the keystore the entry identified by alias.
The user is prompted for the alias, if no alias is provided at
the command line.
-changealias {-alias alias} [-destalias destalias] [-keypass
keypass] {-storetype storetype} {-keystore keystore}
[-storepass
storepass] {-providerName provider_name} {-providerClass
provider_class_name {-providerArg provider_arg}} {-v}
{-protected}
{-Jjavaoption}
Move an existing keystore entry from the specified alias
to a new alias, destalias. If no destination alias is
provided, the command will prompt for one. If the original entry
is protected with an entry password, the password can be supplied
via the "-keypass" option. If no key password is provided, the
storepass (if given) will be attempted first. If that
attempt fails, the user will be prompted for a password.
Getting Help
-help
Lists the basic commands and their options.
For more information about a specific command, enter the
following, where command_name is the name of the command:
keytool -command_name -help
command and option notes
The various commands and their options are listed and described
below. Note:
o
All command and option names are preceded by a minus sign (-).
o
The options for each command may be provided in any order.
o
All items not italicized or in braces or square brackets are
required to appear as is.
o
Braces surrounding an option generally signify that a default
value will be used if the option is not specified on the command
line. Braces are also used around the -v, -rfc, and
-J options, which only have meaning if they appear on the
command line (that is, they don’t have any "default" values other
than not existing).
o
Brackets surrounding an option signify that the user is prompted
for the value(s) if the option is not specified on the command
line. (For a -keypass option, if you do not specify the
option on the command line, keytool will first attempt to
use the keystore password to recover the private/secret key, and
if this fails, will then prompt you for the private/secret key
password.)
o
Items in italics (option values) represent the actual values that
must be supplied. For example, here is the format of the
-printcert command:
keytool -printcert {-file cert_file}
{-v}
When specifying a -printcert command, replace
cert_file with the actual file name, as in:
keytool -printcert -file VScert.cer
o
Option values must be quoted if they contain a blank (space).
o
The -help command is the default. Thus, the command line
keytool
is equivalent to
keytool -help
Option Defaults
Below are the defaults for various option values.
-alias "mykey"
-keyalg
"DSA" (when using -genkeypair)
"DES" (when using -genseckey)
-keysize
2048 (when using -genkeypair and -keyalg is "RSA")
1024 (when using -genkeypair and -keyalg is "DSA")
256 (when using -genkeypair and -keyalg is "EC")
56 (when using -genseckey and -keyalg is "DES")
168 (when using -genseckey and -keyalg is "DESede")
-validity 90
-keystore the file named .keystore in the
user’s home directory
-storetype the value of the "keystore.type" property in the
security properties file,
which is returned by the static getDefaultType
method in
java.security.KeyStore
-file stdin if reading, stdout if writing
-protected false
In generating a public/private key pair, the signature algorithm
(-sigalg option) is derived from the algorithm of the
underlying private key:
o
If the underlying private key is of type "DSA", the
-sigalg option defaults to "SHA1withDSA"
o
If the underlying private key is of type "RSA", the
-sigalg option defaults to "SHA256withRSA".
o
If the underlying private key is of type "EC", the -sigalg
option defaults to "SHA256withECDSA".
Please consult the Java Cryptography Architecture API
Specification & Reference @
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/CryptoSpec.html#AppA
for a full list of -keyalg and -sigalg you can
choose from.
Common Options
The -v option can appear for all commands except
-help. If it appears, it signifies "verbose" mode; more
information will be provided in the output.
There is also a -Jjavaoption option that may appear for
any command. If it appears, the specified javaoption
string is passed through directly to the Java interpreter. This
option should not contain any spaces. It is useful for adjusting
the execution environment or memory usage. For a list of possible
interpreter options, type java -h or java -X at the
command line.
These options may appear for all commands operating on a
keystore:
-storetype storetype
This qualifier specifies the type of keystore to be
instantiated.
-keystore keystore
The keystore location.
If the JKS storetype is used and a keystore file does not yet
exist, then certain keytool commands may result in a new
keystore file being created. For example, if keytool
-genkeypair is invoked and the -keystore option is not
specified, the default keystore file named .keystore in
the user’s home directory will be created if it does not already
exist. Similarly, if the -keystore ks_file option is
specified but ks_file does not exist, then it will be
created
Note that the input stream from the -keystore option is
passed to the KeyStore.load method. If NONE is
specified as the URL, then a null stream is passed to the
KeyStore.load method. NONE should be specified if
the KeyStore is not file-based (for example, if it resides
on a hardware token device).
-storepass[:env|:file] argument
The password which is used to protect the integrity of the
keystore.
If the modifier env or file is not specified, then
the password has the value argument, which must be at
least 6 characters long. Otherwise, the password is retrieved as
follows:
o
env: Retrieve the password from the environment variable
named argument
o
file: Retrieve the password from the file named
argument
Note: All other options that require passwords, such as
-keypass, -srckeypass, -destkeypass
-srcstorepass, and -deststorepass, accept the
env and file modifiers. (Remember to separate the
password option and the modifier with a colon, (:).)
The password must be provided to all commands that access the
keystore contents. For such commands, if a -storepass
option is not provided at the command line, the user is prompted
for it.
When retrieving information from the keystore, the password is
optional; if no password is given, the integrity of the retrieved
information cannot be checked and a warning is displayed.
-providerName provider_name
Used to identify a cryptographic service provider’s name when
listed in the security properties file.
-providerClass provider_class_name
Used to specify the name of cryptographic service provider’s
master class file when the service provider is not listed in the
security properties file.
-providerArg provider_arg
Used in conjunction with -providerClass. Represents an
optional string input argument for the constructor of
provider_class_name.
-protected
Either true or false. This value should be
specified as true if a password must be given via a
protected authentication path such as a dedicated PIN reader.
Note: Since there are two keystores involved in
-importkeystore command, two options, namely,
-srcprotected and -destprotected are provided for
the source keystore and the destination keystore
respectively.
-ext {name{:critical}{=value}}
Denotes an X.509 certificate extension. The option can be used in
-genkeypair and -gencert to embed extensions into the certificate
generated, or in -certreq to show what extensions are
requested in the certificate request. The option can appear
multiple times. name can be a supported extension name (see
below) or an arbitrary OID number. value, if provided, denotes
the parameter for the extension; if omitted, denotes the default
value (if defined) of the extension or the extension requires no
parameter. The :critical modifier, if provided, means the
extension’s isCritical attribute is true; otherwise, false. You
may use :c in place of :critical.
Currently keytool supports these named extensions
(case-insensitive):
For name as OID, value is the HEX dumped DER encoding of the
extnValue for the extension excluding the OCTET STRING type and
length bytes. Any extra character other than standard HEX numbers
(0-9, a-f, A-F) are ignored in the HEX string. Therefore, both
"01:02:03:04" and "01020304" are accepted as
identical values. If there is no value, the extension has an
empty value field then.
A special name ’honored’, used in -gencert only,
denotes how the extensions included in the certificate request
should be honored. The value for this name is a comma separated
list of "all" (all requested extensions are honored),
"name{:[critical|non-critical]}" (the named extension is
honored, but using a different isCritical attribute) and
"-name" (used with all, denotes an exception). Requested
extensions are not honored by default.
If, besides the -ext honored option, another named or OID -ext
option is provided, this extension will be added to those already
honored. However, if this name (or OID) also appears in the
honored value, its value and criticality overrides the one in the
request.
The subjectKeyIdentifier extension is always created. For non
self-signed certificates, the authorityKeyIdentifier is always
created.
Note: Users should be aware that some combinations of
extensions (and other certificate fields) may not conform to the
Internet standard. See Warning Regarding Certificate Conformance
for details.
if the alias does not point
Certificate
Before adding the certificate to the keystore, keytool
tries to verify it by attempting to construct a chain of trust
from that certificate to a self-signed certificate (belonging to
a root CA), using trusted certificates that are already available
in the keystore.
If the -trustcacerts option has been specified, additional
certificates are considered for the chain of trust, namely the
certificates in a file named "cacerts".
If keytool fails to establish a trust path from the
certificate to be imported up to a self-signed certificate
(either from the keystore or the "cacerts" file), the certificate
information is printed out, and the user is prompted to verify
it, e.g., by comparing the displayed certificate fingerprints
with the fingerprints obtained from some other (trusted) source
of information, which might be the certificate owner
himself/herself. Be very careful to ensure the certificate is
valid prior to importing it as a "trusted" certificate! -- see
WARNING Regarding Importing Trusted Certificates. The user then
has the option of aborting the import operation. If the
-noprompt option is given, however, there will be no
interaction with the user. Importing a Certificate Reply
When importing a certificate reply, the certificate reply is
validated using trusted certificates from the keystore, and
optionally using the certificates configured in the "cacerts"
keystore file (if the -trustcacerts option was specified).
The methods of determining whether the certificate reply is
trusted are described in the following:
o
if the reply is a single
Data
-certreq {-alias alias} {-dname dname} {-sigalg sigalg}
{-file
certreq_file} [-keypass keypass] {-storetype storetype}
{-keystore
keystore} [-storepass storepass] {-providerName
provider_name}
{-providerClass provider_class_name {-providerArg
provider_arg}}
{-v} {-protected} {-Jjavaoption}
Generates a Certificate Signing Request (CSR), using the PKCS#10
format.
A CSR is intended to be sent to a certificate authority (CA). The
CA will authenticate the certificate requestor (usually off-line)
and will return a certificate or certificate chain, used to
replace the existing certificate chain (which initially consists
of a self-signed certificate) in the keystore.
The private key associated with alias is used to create
the PKCS#10 certificate request. In order to access the private
key, the appropriate password must be provided, since private
keys are protected in the keystore with a password. If
keypass is not provided at the command line, and is
different from the password used to protect the integrity of the
keystore, the user is prompted for it. If dname is provided, it’s
used as the subject in the CSR. Otherwise, the X.500
Distinguished Name associated with alias is used.
sigalg specifies the algorithm that should be used to sign
the CSR.
The CSR is stored in the file certreq_file. If no file is
given, the CSR is output to stdout.
Use the importcert command to import the response from the
CA.
-exportcert {-alias alias} {-file cert_file} {-storetype
storetype}
{-keystore keystore} [-storepass storepass] {-providerName
provider_name} {-providerClass provider_class_name
{-providerArg
provider_arg}} {-rfc} {-v} {-protected} {-Jjavaoption}
Reads (from the keystore) the certificate associated with
alias, and stores it in the file cert_file.
If no file is given, the certificate is output to stdout.
The certificate is by default output in binary encoding, but will
instead be output in the printable encoding format, as defined by
the Internet RFC 1421 standard, if the -rfc option is
specified.
If alias refers to a trusted certificate, that certificate
is output. Otherwise, alias refers to a key entry with an
associated certificate chain. In that case, the first certificate
in the chain is returned. This certificate authenticates the
public key of the entity addressed by alias.
This command was named -export in previous releases. This
old name is still supported in this release and will be supported
in future releases, but for clarify the new name,
-exportcert, is preferred going forward.
Displaying Data
-list {-alias alias} {-storetype storetype} {-keystore
keystore}
[-storepass storepass] {-providerName provider_name}
{-providerClass
provider_class_name {-providerArg provider_arg}} {-v | -rfc}
{-protected} {-Jjavaoption}
Prints (to stdout) the contents of the keystore entry identified
by alias. If no alias is specified, the contents of the
entire keystore are printed.
This command by default prints the SHA1 fingerprint of a
certificate. If the -v option is specified, the
certificate is printed in human-readable format, with additional
information such as the owner, issuer, serial number, and any
extensions. If the -rfc option is specified, certificate
contents are printed using the printable encoding format, as
defined by the Internet RFC 1421 standard
You cannot specify both -v and -rfc.
-printcert {-file cert_file | -sslserver host[:port]}
{-jarfile
JAR_file {-rfc} {-v} {-Jjavaoption}
Reads the certificate from the file cert_file, the SSL
server located at host:port, or the signed JAR file
JAR_file (with the option -jarfile and prints its
contents in a human-readable format. When no port is specified,
the standard HTTPS port 443 is assumed. Note that
-sslserver and -file options cannot be provided at
the same time. Otherwise, an error is reported. If neither option
is given, the certificate is read from stdin.
If -rfc is specified, keytool prints the certificate in
PEM mode as defined by the Internet RFC 1421 standard.
If the certificate is read from a file or stdin, it may be either
binary encoded or in printable encoding format, as defined by the
Internet RFC 1421 standard
If the SSL server is behind a firewall,
-J-Dhttps.proxyHost=proxyhost and
-J-Dhttps.proxyPort=proxyport can be specified on the
command line for proxy tunneling. See the JSSE Reference
Guide @
http://docs.oracle.com/javase/7/docs/technotes/guides/security/jsse/JSSERefGuide.html
for more information.
Note: This option can be used independently of a
keystore.
-printcrl -file crl_ {-v}
Reads the certificate revocation list (CRL) from the file
crl_file.
A Certificate Revocation List (CRL) is a list of digital
certificates which have been revoked by the Certificate Authority
(CA) that issued them. The CA generates crl_file.
Note: This option can be used independently of a keystore.
Managing the Keystore
-storepasswd [-new new_storepass] {-storetype storetype}
{-keystore
keystore} [-storepass storepass] {-providerName
provider_name}
{-providerClass provider_class_name {-providerArg
provider_arg}}
{-v} {-Jjavaoption}
Changes the password used to protect the integrity of the
keystore contents. The new password is new_storepass,
which must be at least 6 characters long.
-keypasswd {-alias alias} [-keypass old_keypass] [-new
new_keypass]
{-storetype storetype} {-keystore keystore} [-storepass
storepass]
{-providerName provider_name} {-providerClass
provider_class_name
{-providerArg provider_arg}} {-v} {-Jjavaoption}
Changes the password under which the private/secret key
identified by alias is protected, from old_keypass
to new_keypass, which must be at least 6 characters long.
If the -keypass option is not provided at the command
line, and the key password is different from the keystore
password, the user is prompted for it.
If the -new option is not provided at the command line,
the user is prompted for it.
-delete [-alias alias] {-storetype storetype} {-keystore
keystore}
[-storepass storepass] {-providerName provider_name}
{-providerClass
provider_class_name {-providerArg provider_arg}} {-v}
{-protected}
{-Jjavaoption}
Deletes from the keystore the entry identified by alias.
The user is prompted for the alias, if no alias is provided at
the command line.
-changealias {-alias alias} [-destalias destalias] [-keypass
keypass] {-storetype storetype} {-keystore keystore}
[-storepass
storepass] {-providerName provider_name} {-providerClass
provider_class_name {-providerArg provider_arg}} {-v}
{-protected}
{-Jjavaoption}
Move an existing keystore entry from the specified alias
to a new alias, destalias. If no destination alias is
provided, the command will prompt for one. If the original entry
is protected with an entry password, the password can be supplied
via the "-keypass" option. If no key password is provided, the
storepass (if given) will be attempted first. If that
attempt fails, the user will be prompted for a password.
Getting Help
-help
Lists the basic commands and their options.
For more information about a specific command, enter the
following, where command_name is the name of the command:
keytool -command_name -help
keystore
Implementation
The KeyStore class provided in the java.security
package supplies well-defined interfaces to access and modify the
information in a keystore. It is possible for there to be
multiple different concrete implementations, where each
implementation is that for a particular type of keystore.
Currently, two command-line tools (keytool and
jarsigner) and a GUI-based tool named Policy Tool
make use of keystore implementations. Since KeyStore is
publicly available, users can write additional security
applications that use it.
There is a built-in default implementation, provided by Oracle.
It implements the keystore as a file, utilizing a proprietary
keystore type (format) named "JKS". It protects each private key
with its individual password, and also protects the integrity of
the entire keystore with a (possibly different) password.
Keystore implementations are provider-based. More specifically,
the application interfaces supplied by KeyStore are
implemented in terms of a "Service Provider Interface" (SPI).
That is, there is a corresponding abstract KeystoreSpi
class, also in the java.security package, which defines
the Service Provider Interface methods that "providers" must
implement. (The term "provider" refers to a package or a set of
packages that supply a concrete implementation of a subset of
services that can be accessed by the Java Security API.) Thus, to
provide a keystore implementation, clients must implement a
"provider" and supply a KeystoreSpi subclass implementation, as
described in How to Implement a Provider for the Java
Cryptography Architecture @
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/HowToImplAProvider.html.
Applications can choose different types of keystore
implementations from different providers, using the "getInstance"
factory method supplied in the KeyStore class. A keystore
type defines the storage and data format of the keystore
information, and the algorithms used to protect private/secret
keys in the keystore and the integrity of the keystore itself.
Keystore implementations of different types are not compatible.
keytool works on any file-based keystore implementation.
(It treats the keystore location that is passed to it at the
command line as a filename and converts it to a FileInputStream,
from which it loads the keystore information.) The
jarsigner and policytool tools, on the other hand,
can read a keystore from any location that can be specified using
a URL.
For keytool and jarsigner, you can specify a
keystore type at the command line, via the -storetype
option. For Policy Tool, you can specify a keystore type
via the "Keystore" menu.
If you don’t explicitly specify a keystore type, the tools choose
a keystore implementation based simply on the value of the
keystore.type property specified in the security
properties file. The security properties file is called
java.security, and it resides in the security properties
directory, java.home/lib/security, where java.home
is the runtime environment’s directory (the jre directory
in the SDK or the top-level directory of the Java 2 Runtime
Environment).
Each tool gets the keystore.type value and then examines
all the currently-installed providers until it finds one that
implements keystores of that type. It then uses the keystore
implementation from that provider.
The KeyStore class defines a static method named
getDefaultType that lets applications and applets retrieve
the value of the keystore.type property. The following
line of code creates an instance of the default keystore type (as
specified in the keystore.type property):
KeyStore keyStore =
KeyStore.getInstance(KeyStore.getDefaultType());
The default keystore type is "jks" (the proprietary type of the
keystore implementation provided by Oracle). This is specified by
the following line in the security properties file:
keystore.type=jks
To have the tools utilize a keystore implementation other than
the default, you can change that line to specify a different
keystore type.
For example, if you have a provider package that supplies a
keystore implementation for a keystore type called "pkcs12",
change the line to
keystore.type=pkcs12
Note: case doesn’t matter in keystore type designations. For
example, "JKS" would be considered the same as "jks".
Certificate
A certificate (also known as a public-key
certificate) is a digitally signed statement from one entity
(the issuer), saying that the public key (and some other
information) of another entity (the subject) has some
specific value.
o
terminology and warnings
KeyStore
A keystore is a storage facility for cryptographic keys and
certificates.
o
KeyStore Entries
Keystores may have different types of entries. The two most
applicable entry types for keytool include:
1.
key entries - each holds very sensitive cryptographic key
information, which is stored in a protected format to prevent
unauthorized access. Typically, a key stored in this type of
entry is a secret key, or a private key accompanied by the
certificate "chain" for the corresponding public key. The
keytool can handle both types of entries, while the
jarsigner tool only handle the latter type of entry, that
is private keys and their associated certificate chains.
2.
trusted certificate entries - each contains a single
public key certificate belonging to another party. It is called a
"trusted certificate" because the keystore owner trusts that the
public key in the certificate indeed belongs to the identity
identified by the "subject" (owner) of the certificate. The
issuer of the certificate vouches for this, by signing the
certificate.
o
KeyStore Aliases
All keystore entries (key and trusted certificate entries) are
accessed via unique aliases.
An alias is specified when you add an entity to the keystore
using the -genseckey command to generate a secret key,
-genkeypair command to generate a key pair (public and private
key) or the -importcert command to add a certificate or
certificate chain to the list of trusted certificates. Subsequent
keytool commands must use this same alias to refer to the
entity.
For example, suppose you use the alias duke to generate a
new public/private key pair and wrap the public key into a
self-signed certificate (see Certificate Chains) via the
following command:
keytool -genkeypair -alias duke -keypass dukekeypasswd
This specifies an initial password of "dukekeypasswd" required by
subsequent commands to access the private key associated with the
alias duke. If you later want to change duke’s private key
password, you use a command like the following:
keytool -keypasswd -alias duke -keypass dukekeypasswd -new
newpass
This changes the password from "dukekeypasswd" to "newpass".
Please note: A password should not actually be specified on a
command line or in a script unless it is for testing purposes, or
you are on a secure system. If you don’t specify a required
password option on a command line, you will be prompted for it.
o
KeyStore Implementation
The KeyStore class provided in the java.security
package supplies well-defined interfaces to access and modify the
information in a keystore. It is possible for there to be
multiple different concrete implementations, where each
implementation is that for a particular type of keystore.
Currently, two command-line tools (keytool and
jarsigner) and a GUI-based tool named Policy Tool
make use of keystore implementations. Since KeyStore is
publicly available, users can write additional security
applications that use it.
There is a built-in default implementation, provided by Oracle.
It implements the keystore as a file, utilizing a proprietary
keystore type (format) named "JKS". It protects each private key
with its individual password, and also protects the integrity of
the entire keystore with a (possibly different) password.
Keystore implementations are provider-based. More specifically,
the application interfaces supplied by KeyStore are
implemented in terms of a "Service Provider Interface" (SPI).
That is, there is a corresponding abstract KeystoreSpi
class, also in the java.security package, which defines
the Service Provider Interface methods that "providers" must
implement. (The term "provider" refers to a package or a set of
packages that supply a concrete implementation of a subset of
services that can be accessed by the Java Security API.) Thus, to
provide a keystore implementation, clients must implement a
"provider" and supply a KeystoreSpi subclass implementation, as
described in How to Implement a Provider for the Java
Cryptography Architecture @
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/HowToImplAProvider.html.
Applications can choose different types of keystore
implementations from different providers, using the "getInstance"
factory method supplied in the KeyStore class. A keystore
type defines the storage and data format of the keystore
information, and the algorithms used to protect private/secret
keys in the keystore and the integrity of the keystore itself.
Keystore implementations of different types are not compatible.
keytool works on any file-based keystore implementation.
(It treats the keystore location that is passed to it at the
command line as a filename and converts it to a FileInputStream,
from which it loads the keystore information.) The
jarsigner and policytool tools, on the other hand,
can read a keystore from any location that can be specified using
a URL.
For keytool and jarsigner, you can specify a
keystore type at the command line, via the -storetype
option. For Policy Tool, you can specify a keystore type
via the "Keystore" menu.
If you don’t explicitly specify a keystore type, the tools choose
a keystore implementation based simply on the value of the
keystore.type property specified in the security
properties file. The security properties file is called
java.security, and it resides in the security properties
directory, java.home/lib/security, where java.home
is the runtime environment’s directory (the jre directory
in the SDK or the top-level directory of the Java 2 Runtime
Environment).
Each tool gets the keystore.type value and then examines
all the currently-installed providers until it finds one that
implements keystores of that type. It then uses the keystore
implementation from that provider.
The KeyStore class defines a static method named
getDefaultType that lets applications and applets retrieve
the value of the keystore.type property. The following
line of code creates an instance of the default keystore type (as
specified in the keystore.type property):
KeyStore keyStore =
KeyStore.getInstance(KeyStore.getDefaultType());
The default keystore type is "jks" (the proprietary type of the
keystore implementation provided by Oracle). This is specified by
the following line in the security properties file:
keystore.type=jks
To have the tools utilize a keystore implementation other than
the default, you can change that line to specify a different
keystore type.
For example, if you have a provider package that supplies a
keystore implementation for a keystore type called "pkcs12",
change the line to
keystore.type=pkcs12
Note: case doesn’t matter in keystore type designations. For
example, "JKS" would be considered the same as "jks".
Certificate
A certificate (also known as a public-key
certificate) is a digitally signed statement from one entity
(the issuer), saying that the public key (and some other
information) of another entity (the subject) has some
specific value.
o
Certificate Terms
Public Keys
These are numbers associated with a particular entity, and are
intended to be known to everyone who needs to have trusted
interactions with that entity. Public keys are used to verify
signatures.
Digitally Signed
If some data is digitally signed it has been stored with
the "identity" of an entity, and a signature that proves that
entity knows about the data. The data is rendered unforgeable by
signing with the entity’s private key.
Identity
A known way of addressing an entity. In some systems the identity
is the public key, in others it can be anything from a Unix UID
to an Email address to an X.509 Distinguished Name.
Signature
A signature is computed over some data using the private key of
an entity (the signer, which in the case of a certificate
is also known as the issuer).
Private Keys
These are numbers, each of which is supposed to be known only to
the particular entity whose private key it is (that is, it’s
supposed to be kept secret). Private and public keys exist in
pairs in all public key cryptography systems (also referred to as
"public key crypto systems"). In a typical public key crypto
system, such as DSA, a private key corresponds to exactly one
public key. Private keys are used to compute signatures.
Entity
An entity is a person, organization, program, computer, business,
bank, or something else you are trusting to some degree.
Basically, public key cryptography requires access to users’
public keys. In a large-scale networked environment it is
impossible to guarantee that prior relationships between
communicating entities have been established or that a trusted
repository exists with all used public keys. Certificates were
invented as a solution to this public key distribution problem.
Now a Certification Authority (CA) can act as a trusted
third party. CAs are entities (for example, businesses) that are
trusted to sign (issue) certificates for other entities. It is
assumed that CAs will only create valid and reliable
certificates, as they are bound by legal agreements. There are
many public Certification Authorities, such as VeriSign
@
http://www.verisign.com/, Thawte @
http://www.thawte.com/, Entrust @
http://www.entrust.com/, and so on. You can also run your own
Certification Authority using products such as Microsoft
Certificate Server or the Entrust CA product for your
organization.
Using keytool, it is possible to display, import, and
export certificates. It is also possible to generate self-signed
certificates.
keytool currently handles X.509 certificates.
o
X.509 Certificates
The X.509 standard defines what information can go into a
certificate, and describes how to write it down (the data
format). All the data in a certificate is encoded using two
related standards called ASN.1/DER. Abstract Syntax Notation
1 describes data. The Definite Encoding Rules describe
a single way to store and transfer that data.
All X.509 certificates have the following data, in addition to
the signature:
Version
This identifies which version of the X.509 standard applies to
this certificate, which affects what information can be specified
in it. Thus far, three versions are defined. keytool can
import and export v1, v2, and v3 certificates. It generates v3
certificates.
X.509 Version 1 has been available since 1988, is widely
deployed, and is the most generic.
X.509 Version 2 introduced the concept of subject and
issuer unique identifiers to handle the possibility of reuse of
subject and/or issuer names over time. Most certificate profile
documents strongly recommend that names not be reused, and that
certificates should not make use of unique identifiers. Version 2
certificates are not widely used.
X.509 Version 3 is the most recent (1996) and supports the
notion of extensions, whereby anyone can define an extension and
include it in the certificate. Some common extensions in use
today are: KeyUsage (limits the use of the keys to
particular purposes such as "signing-only") and
AlternativeNames (allows other identities to also be
associated with this public key, e.g. DNS names, Email addresses,
IP addresses). Extensions can be marked critical to
indicate that the extension should be checked and enforced/used.
For example, if a certificate has the KeyUsage extension marked
critical and set to "keyCertSign" then if this certificate is
presented during SSL communication, it should be rejected, as the
certificate extension indicates that the associated private key
should only be used for signing certificates and not for SSL
use.
Serial Number
The entity that created the certificate is responsible for
assigning it a serial number to distinguish it from other
certificates it issues. This information is used in numerous
ways, for example when a certificate is revoked its serial number
is placed in a Certificate Revocation List (CRL).
Signature Algorithm Identifier
This identifies the algorithm used by the CA to sign the
certificate.
Issuer Name
The X.500 Distinguished Name of the entity that signed the
certificate. This is normally a CA. Using this certificate
implies trusting the entity that signed this certificate. (Note
that in some cases, such as root or top-level CA
certificates, the issuer signs its own certificate.)
Validity Period
Each certificate is valid only for a limited amount of time. This
period is described by a start date and time and an end date and
time, and can be as short as a few seconds or almost as long as a
century. The validity period chosen depends on a number of
factors, such as the strength of the private key used to sign the
certificate or the amount one is willing to pay for a
certificate. This is the expected period that entities can rely
on the public value, if the associated private key has not been
compromised.
Subject Name
The name of the entity whose public key the certificate
identifies. This name uses the X.500 standard, so it is intended
to be unique across the Internet. This is the X.500 Distinguished
Name (DN) of the entity, for example,
CN=Java Duke, OU=Java Software Division, O=Oracle Corporation,
C=US
(These refer to the subject’s Common Name, Organizational Unit,
Organization, and Country.)
Subject Public Key Information
This is the public key of the entity being named, together with
an algorithm identifier which specifies which public key crypto
system this key belongs to and any associated key parameters.
o
Certificate Chains
keytool can create and manage keystore "key" entries that
each contain a private key and an associated certificate "chain".
The first certificate in the chain contains the public key
corresponding to the private key.
When keys are first generated (see the -genkeypair command), the
chain starts off containing a single element, a self-signed
certificate. A self-signed certificate is one for which the
issuer (signer) is the same as the subject (the entity whose
public key is being authenticated by the certificate). Whenever
the -genkeypair command is called to generate a new
public/private key pair, it also wraps the public key into a
self-signed certificate.
Later, after a Certificate Signing Request (CSR) has been
generated (see the -certreq command) and sent to a Certification
Authority (CA), the response from the CA is imported (see
-importcert), and the self-signed certificate is replaced by a
chain of certificates. At the bottom of the chain is the
certificate (reply) issued by the CA authenticating the subject’s
public key. The next certificate in the chain is one that
authenticates the CA’s public key.
In many cases, this is a self-signed certificate (that is, a
certificate from the CA authenticating its own public key) and
the last certificate in the chain. In other cases, the CA may
return a chain of certificates. In this case, the bottom
certificate in the chain is the same (a certificate signed by the
CA, authenticating the public key of the key entry), but the
second certificate in the chain is a certificate signed by a
different CA, authenticating the public key of the CA you
sent the CSR to. Then, the next certificate in the chain will be
a certificate authenticating the second CA’s key, and so on,
until a self-signed "root" certificate is reached. Each
certificate in the chain (after the first) thus authenticates the
public key of the signer of the previous certificate in the
chain.
Many CAs only return the issued certificate, with no supporting
chain, especially when there is a flat hierarchy (no
intermediates CAs). In this case, the certificate chain must be
established from trusted certificate information already stored
in the keystore.
A different reply format (defined by the PKCS#7 standard) also
includes the supporting certificate chain, in addition to the
issued certificate. Both reply formats can be handled by
keytool.
The top-level (root) CA certificate is self-signed. However, the
trust into the root’s public key does not come from the root
certificate itself (anybody could generate a self-signed
certificate with the distinguished name of say, the VeriSign root
CA!), but from other sources like a newspaper. The root CA public
key is widely known. The only reason it is stored in a
certificate is because this is the format understood by most
tools, so the certificate in this case is only used as a
"vehicle" to transport the root CA’s public key. Before you add
the root CA certificate to your keystore, you should view it
(using the -printcert option) and compare the displayed
fingerprint with the well-known fingerprint (obtained from a
newspaper, the root CA’s Web page, etc.).
o
The cacerts Certificates File
A certificates file named "cacerts" resides in the
security properties directory, java.home/lib/security,
where java.home is the runtime environment’s directory
(the jre directory in the SDK or the top-level directory
of the Java 2 Runtime Environment).
The "cacerts" file represents a system-wide keystore with CA
certificates. System administrators can configure and manage that
file using keytool, specifying "jks" as the keystore type.
The "cacerts" keystore file ships with a default set of root CA
certificates; list them with the following command:
keytool -list -keystore
java.home/lib/security/cacerts
The initial password of the "cacerts" keystore file is
"changeit". System administrators should change that password and
the default access permission of that file upon installing the
SDK.
IMPORTANT: Verify Your cacerts File:
Since you trust the CAs in the cacerts file as entities
for signing and issuing certificates to other entities, you must
manage the cacerts file carefully. The cacerts file
should contain only certificates of the CAs you trust. It is your
responsibility to verify the trusted root CA certificates bundled
in the cacerts file and make your own trust decisions. To
remove an untrusted CA certificate from the cacerts file,
use the delete option of the keytool command. You can find
the cacerts file in the JRE installation directory.
Contact your system administrator if you do not have permission
to edit this file.
o
The Internet RFC 1421 Certificate Encoding Standard
Certificates are often stored using the printable encoding format
defined by the Internet RFC 1421 standard, instead of their
binary encoding. This certificate format, also known as "Base 64
encoding", facilitates exporting certificates to other
applications by email or through some other mechanism.
Certificates read by the -importcert and -printcert
commands can be in either this format or binary encoded.
The -exportcert command by default outputs a certificate
in binary encoding, but will instead output a certificate in the
printable encoding format, if the -rfc option is
specified.
The -list command by default prints the SHA1 fingerprint
of a certificate. If the -v option is specified, the
certificate is printed in human-readable format, while if the
-rfc option is specified, the certificate is output in the
printable encoding format.
In its printable encoding format, the encoded certificate is
bounded at the beginning by
-----BEGIN CERTIFICATE-----
and at the end by
-----END CERTIFICATE-----
X.500 Distinguished Names
X.500 Distinguished Names are used to identify entities, such as
those which are named by the subject and issuer
(signer) fields of X.509 certificates. keytool supports
the following subparts:
o
commonName - common name of a person, e.g., "Susan Jones"
o
organizationUnit - small organization (e.g., department or
division) name, e.g., "Purchasing"
o
organizationName - large organization name, e.g.,
"ABCSystems, Inc."
o
localityName - locality (city) name, e.g., "Palo Alto"
o
stateName - state or province name, e.g., "California"
o
country - two-letter country code, e.g., "CH"
When supplying a distinguished name string as the value of a
-dname option, as for the -genkeypair command, the
string must be in the following format:
CN=cName,
OU=orgUnit, O=org,
L=city, S=state,
C=countryCode
where all the italicized items represent actual values and the
above keywords are abbreviations for the following:
CN=commonName
OU=organizationUnit
O=organizationName
L=localityName
S=stateName
C=country
A sample distinguished name string is
CN=Mark Smith, OU=Java, O=Oracle, L=Cupertino, S=California,
C=US
and a sample command using such a string is
keytool -genkeypair -dname "CN=Mark Smith, OU=Java, O=Oracle,
L=Cupertino,
S=California, C=US" -alias mark
Case does not matter for the keyword abbreviations. For example,
"CN", "cn", and "Cn" are all treated the same.
Order matters; each subcomponent must appear in the designated
order. However, it is not necessary to have all the
subcomponents. You may use a subset, for example:
CN=Steve Meier, OU=Java, O=Oracle, C=US
If a distinguished name string value contains a comma, the comma
must be escaped by a "\" character when you specify the string on
a command line, as in
cn=Peter Schuster, ou=Java\, Product Development, o=Oracle,
c=US
It is never necessary to specify a distinguished name string on a
command line. If it is needed for a command, but not supplied on
the command line, the user is prompted for each of the
subcomponents. In this case, a comma does not need to be escaped
by a "\".
WARNING Regarding Importing Trusted Certificates
IMPORTANT: Be sure to check a certificate very carefully before
importing it as a trusted certificate!
View it first (using the -printcert command, or the
-importcert command without the -noprompt option),
and make sure that the displayed certificate fingerprint(s) match
the expected ones. For example, suppose someone sends or emails
you a certificate, and you put it in a file named
/tmp/cert. Before you consider adding the certificate to
your list of trusted certificates, you can execute a
-printcert command to view its fingerprints, as in
keytool -printcert -file /tmp/cert
Owner: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Issuer: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Serial Number: 59092b34
Valid from: Thu Sep 25 18:01:13 PDT 1997 until: Wed Dec 24
17:01:13 PST 1997
Certificate Fingerprints:
MD5: 11:81:AD:92:C8:E5:0E:A2:01:2E:D4:7A:D7:5F:07:6F
SHA1:
20:B6:17:FA:EF:E5:55:8A:D0:71:1F:E8:D6:9D:C0:37:13:0E:5E:FE
SHA256: 90:7B:70:0A:EA:DC:16:79:92:99:41:FF:8A:FE:EB:90:
17:75:E0:90:B2:24:4D:3A:2A:16:A6:E4:11:0F:67:A4
Then call or otherwise contact the person who sent the
certificate, and compare the fingerprint(s) that you see with the
ones that they show. Only if the fingerprints are equal is it
guaranteed that the certificate has not been replaced in transit
with somebody else’s (for example, an attacker’s) certificate. If
such an attack took place, and you did not check the certificate
before you imported it, you would end up trusting anything the
attacker has signed (for example, a JAR file with malicious class
files inside).
Note: it is not required that you execute a -printcert
command prior to importing a certificate, since before adding a
certificate to the list of trusted certificates in the keystore,
the -importcert command prints out the certificate
information and prompts you to verify it. You then have the
option of aborting the import operation. Note, however, this is
only the case if you invoke the -importcert command
without the -noprompt option. If the -noprompt
option is given, there is no interaction with the user.
Warning Regarding Passwords
Most commands operating on a keystore require the store password.
Some commands require a private/secret key password.
Passwords can be specified on the command line (in the
-storepass and -keypass options, respectively).
However, a password should not be specified on a command line or
in a script unless it is for testing purposes, or you are on a
secure system.
If you don’t specify a required password option on a command
line, you will be prompted for it.
Warning Regarding Certificate Conformance
The Internet standard RFC 5280 @
http://tools.ietf.org/rfc/rfc5280.txt has defined a profile on
conforming X.509 certificates, which includes what values and
value combinations are valid for certificate fields and
extensions. keytool has not enforced all these rules so it
can generate certificates which do not conform to the standard,
and these certificates might be rejected by JRE or other
applications. Users should make sure that they provide the
correct options for -dname, -ext, etc.
the internet rfc 1421
Certificate Encoding Standard
Certificates are often stored using the printable encoding format
defined by the Internet RFC 1421 standard, instead of their
binary encoding. This certificate format, also known as "Base 64
encoding", facilitates exporting certificates to other
applications by email or through some other mechanism.
Certificates read by the -importcert and -printcert
commands can be in either this format or binary encoded.
The -exportcert command by default outputs a certificate
in binary encoding, but will instead output a certificate in the
printable encoding format, if the -rfc option is
specified.
The -list command by default prints the SHA1 fingerprint
of a certificate. If the -v option is specified, the
certificate is printed in human-readable format, while if the
-rfc option is specified, the certificate is output in the
printable encoding format.
In its printable encoding format, the encoded certificate is
bounded at the beginning by
-----BEGIN CERTIFICATE-----
and at the end by
-----END CERTIFICATE-----
X.500 Distinguished Names
X.500 Distinguished Names are used to identify entities, such as
those which are named by the subject and issuer
(signer) fields of X.509 certificates. keytool supports
the following subparts:
o
commonName - common name of a person, e.g., "Susan Jones"
o
organizationUnit - small organization (e.g., department or
division) name, e.g., "Purchasing"
o
organizationName - large organization name, e.g.,
"ABCSystems, Inc."
o
localityName - locality (city) name, e.g., "Palo Alto"
o
stateName - state or province name, e.g., "California"
o
country - two-letter country code, e.g., "CH"
When supplying a distinguished name string as the value of a
-dname option, as for the -genkeypair command, the
string must be in the following format:
CN=cName,
OU=orgUnit, O=org,
L=city, S=state,
C=countryCode
where all the italicized items represent actual values and the
above keywords are abbreviations for the following:
CN=commonName
OU=organizationUnit
O=organizationName
L=localityName
S=stateName
C=country
A sample distinguished name string is
CN=Mark Smith, OU=Java, O=Oracle, L=Cupertino, S=California,
C=US
and a sample command using such a string is
keytool -genkeypair -dname "CN=Mark Smith, OU=Java, O=Oracle,
L=Cupertino,
S=California, C=US" -alias mark
Case does not matter for the keyword abbreviations. For example,
"CN", "cn", and "Cn" are all treated the same.
Order matters; each subcomponent must appear in the designated
order. However, it is not necessary to have all the
subcomponents. You may use a subset, for example:
CN=Steve Meier, OU=Java, O=Oracle, C=US
If a distinguished name string value contains a comma, the comma
must be escaped by a "\" character when you specify the string on
a command line, as in
cn=Peter Schuster, ou=Java\, Product Development, o=Oracle,
c=US
It is never necessary to specify a distinguished name string on a
command line. If it is needed for a command, but not supplied on
the command line, the user is prompted for each of the
subcomponents. In this case, a comma does not need to be escaped
by a "\".
WARNING Regarding Importing Trusted Certificates
IMPORTANT: Be sure to check a certificate very carefully before
importing it as a trusted certificate!
View it first (using the -printcert command, or the
-importcert command without the -noprompt option),
and make sure that the displayed certificate fingerprint(s) match
the expected ones. For example, suppose someone sends or emails
you a certificate, and you put it in a file named
/tmp/cert. Before you consider adding the certificate to
your list of trusted certificates, you can execute a
-printcert command to view its fingerprints, as in
keytool -printcert -file /tmp/cert
Owner: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Issuer: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Serial Number: 59092b34
Valid from: Thu Sep 25 18:01:13 PDT 1997 until: Wed Dec 24
17:01:13 PST 1997
Certificate Fingerprints:
MD5: 11:81:AD:92:C8:E5:0E:A2:01:2E:D4:7A:D7:5F:07:6F
SHA1:
20:B6:17:FA:EF:E5:55:8A:D0:71:1F:E8:D6:9D:C0:37:13:0E:5E:FE
SHA256: 90:7B:70:0A:EA:DC:16:79:92:99:41:FF:8A:FE:EB:90:
17:75:E0:90:B2:24:4D:3A:2A:16:A6:E4:11:0F:67:A4
Then call or otherwise contact the person who sent the
certificate, and compare the fingerprint(s) that you see with the
ones that they show. Only if the fingerprints are equal is it
guaranteed that the certificate has not been replaced in transit
with somebody else’s (for example, an attacker’s) certificate. If
such an attack took place, and you did not check the certificate
before you imported it, you would end up trusting anything the
attacker has signed (for example, a JAR file with malicious class
files inside).
Note: it is not required that you execute a -printcert
command prior to importing a certificate, since before adding a
certificate to the list of trusted certificates in the keystore,
the -importcert command prints out the certificate
information and prompts you to verify it. You then have the
option of aborting the import operation. Note, however, this is
only the case if you invoke the -importcert command
without the -noprompt option. If the -noprompt
option is given, there is no interaction with the user.
Warning Regarding Passwords
Most commands operating on a keystore require the store password.
Some commands require a private/secret key password.
Passwords can be specified on the command line (in the
-storepass and -keypass options, respectively).
However, a password should not be specified on a command line or
in a script unless it is for testing purposes, or you are on a
secure system.
If you don’t specify a required password option on a command
line, you will be prompted for it.
Warning Regarding Certificate Conformance
The Internet standard RFC 5280 @
http://tools.ietf.org/rfc/rfc5280.txt has defined a profile on
conforming X.509 certificates, which includes what values and
value combinations are valid for certificate fields and
extensions. keytool has not enforced all these rules so it
can generate certificates which do not conform to the standard,
and these certificates might be rejected by JRE or other
applications. Users should make sure that they provide the
correct options for -dname, -ext, etc.
the cacerts certificates
File
A certificates file named "cacerts" resides in the
security properties directory, java.home/lib/security,
where java.home is the runtime environment’s directory
(the jre directory in the SDK or the top-level directory
of the Java 2 Runtime Environment).
The "cacerts" file represents a system-wide keystore with CA
certificates. System administrators can configure and manage that
file using keytool, specifying "jks" as the keystore type.
The "cacerts" keystore file ships with a default set of root CA
certificates; list them with the following command:
keytool -list -keystore
java.home/lib/security/cacerts
The initial password of the "cacerts" keystore file is
"changeit". System administrators should change that password and
the default access permission of that file upon installing the
SDK.
IMPORTANT: Verify Your cacerts File:
Since you trust the CAs in the cacerts file as entities
for signing and issuing certificates to other entities, you must
manage the cacerts file carefully. The cacerts file
should contain only certificates of the CAs you trust. It is your
responsibility to verify the trusted root CA certificates bundled
in the cacerts file and make your own trust decisions. To
remove an untrusted CA certificate from the cacerts file,
use the delete option of the keytool command. You can find
the cacerts file in the JRE installation directory.
Contact your system administrator if you do not have permission
to edit this file.
o
see also
o
jar tool documentation
o
jarsigner tool documentation
o
the Security @
http://docs.oracle.com/javase/tutorial/security/index.html
trail of the Java Tutorial @
http://docs.oracle.com/javase/tutorial/ for examples of the
use of keytool