jarsigner(1) jarsigner(1)
NAME
jarsigner - JAR Signing and Verification Tool
Generates signatures for Java ARchive (JAR) files, and verifies the
signatures of signed JAR files.
SYNOPSIS
jarsigner [ options ] jar-file alias
jarsigner -verify [ options ] jar-file
DESCRIPTION
The jarsigner tool is used for two purposes:
1. to sign Java ARchive (JAR) files, and
2. to verify the signatures and integrity of signed JAR files.
The JAR feature enables the packaging of class files, images, sounds,
and other digital data in a single file for faster and easier distribu‐
tion. A tool named jar enables developers to produce JAR files. (Tech‐
nically, any zip file can also be considered a JAR file, although when
created by jar or processed by jarsigner, JAR files also contain a
META-INF/MANIFEST.MF file.)
A digital signature is a string of bits that is computed from some data
(the data being "signed") and the private key of an entity (a person,
company, etc.). Like a handwritten signature, a digital signature has
many useful characteristics:
o Its authenticity can be verified, via a computation that uses the
public key corresponding to the private key used to generate the
signature.
o It cannot be forged, assuming the private key is kept secret.
o It is a function of the data signed and thus can't be claimed to
be the signature for other data as well.
o The signed data cannot be changed; if it is, the signature will no
longer verify as being authentic.
In order for an entity's signature to be generated for a file, the
entity must first have a public/private key pair associated with it,
and also one or more certificates authenticating its public key. A cer‐
tificate is a digitally signed statement from one entity, saying that
the public key of some other entity has a particular value.
jarsigner uses key and certificate information from a keystore to gen‐
erate digital signatures for JAR files. A keystore is a database of
private keys and their associated X.509 certificate chains authenticat‐
ing the corresponding public keys. The keytool utility is used to cre‐
ate and administer keystores.
jarsigner uses an entity's private key to generate a signature. The
signed JAR file contains, among other things, a copy of the certificate
from the keystore for the public key corresponding to the private key
used to sign the file. jarsigner can verify the digital signature of
the signed JAR file using the certificate inside it (in its signature
block file).
Starting in J2SE 5.0, jarsigner can generate signatures that include a
timestamp, thus enabling systems/deployer (including Java Plug-in) to
check whether the JAR file was signed while the signing certificate was
still valid. In addition, APIs were added in J2SE 5.0 to allow applica‐
tions to obtain the timestamp information.
At this time, jarsigner can only sign JAR files created by the SDK jar
tool or zip files. (JAR files are the same as zip files, except they
also have a META-INF/MANIFEST.MF file. Such a file will automatically
be created when jarsigner signs a zip file.)
The default jarsigner behavior is to sign a JAR (or zip) file. Use the
-verify option to instead have it verify a signed JAR file.
Compatibility with JDK 1.1
The keytool and jarsigner tools completely replace the javakey tool
provided in JDK 1.1. These new tools provide more features than
javakey, including the ability to protect the keystore and private
keys with passwords, and the ability to verify signatures in addi‐
tion to generating them.
The new keystore architecture replaces the identity database that
javakey created and managed. There is no backwards compatibility
between the keystore format and the database format used by javakey
in 1.1. However,
o It is possible to import the information from an identity data‐
base into a keystore, via the keytool -identitydb command.
o jarsigner can sign JAR files also previously signed using
javakey.
o jarsigner can verify JAR files signed using javakey. Thus, it
recognizes and can work with signer aliases that are from a JDK
1.1 identity database rather than a Java 2 SDK keystore.
The following table explains how JAR files that were signed in JDK
1.1.x are treated in the Java 2 platform.
Notes:
1. If an identity/alias is mentioned in the policy file, it must
be imported into the keystore for the policy file to have any
effect on privileges granted.
2. The policy file/keystore combination has precedence over a
trusted identity in the identity database.
3. Untrusted identities are ignored in the Java 2 platform.
4. Only trusted identities can be imported into Java 2 SDK key‐
stores.
Keystore Aliases
All keystore entities are accessed via unique aliases.
When using jarsigner to sign a JAR file, you must specify the alias
for the keystore entry containing the private key needed to generate
the signature. For example, the following will sign the JAR file
named "MyJARFile.jar", using the private key associated with the
alias "duke" in the keystore named "mystore" in the "working" direc‐
tory. Since no output file is specified, it overwrites MyJARFile.jar
with the signed JAR file.
jarsigner -keystore /working/mystore -storepass myspass
-keypass dukekeypasswd MyJARFile.jar duke
Keystores are protected with a password, so the store password (in
this case "myspass") must be specified. You will be prompted for it
if you don't specify it on the command line. Similarly, private keys
are protected in a keystore with a password, so the private key's
password (in this case "dukekeypasswd") must be specified, and you
will be prompted for it if you don't specify it on the command line
and it isn't the same as the store password.
Keystore Location
jarsigner has a -keystore option for specifying the URL of the key‐
store to be used. The keystore is by default stored in a file named
.keystore in the user's home directory, as determined by the
user.home system property. On Solaris systems user.home defaults to
the user's home directory.
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.
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, there are two command-line tools that make use of key‐
store implementations (keytool and jarsigner), and also a GUI-based
tool named Policy Tool. Since KeyStore is publicly available, Java 2
SDK users can write additional security applications that use it.
There is a built-in default implementation, provided by Sun
Microsystems. It implements the keystore as a file, utilizing a pro‐
prietary keystore type (format) named "JKS". It protects each pri‐
vate key with its individual password, and also protects the
integrity of the entire keystore with a (possibly different) pass‐
word.
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 corre‐
sponding abstract KeystoreSpi class, also in the java.security pack‐
age, 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 sub‐
set 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://java.sun.com/javase/6/docs/technotes/guides/security/HowToIm‐
plAProvider.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 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 keytore 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 jarsigner and keytool, 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 "Change Keystore" command in the
Edit menu.
If you don't explicitly specify a keystore type, the tools choose a
keystore implementation based simply on the value of the key‐
store.type property specified in the security properties file. The
security properties file is called java.security, and it resides in
the SDK 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 Environ‐
ment).
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 key‐
store.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 key‐
store implementation provided by Sun). This is specified by the fol‐
lowing line in the security properties file:
keystore.type=jks
Note: Case doesn't matter in keystore type designations. For exam‐
ple, "JKS" would be considered the same as "jks".
To have the tools utilize a keystore implementation other than the
default, 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 that if you us the PKCS#11 provider package, you should refer
to the KeyTool and JarSigner @
http://java.sun.com/javase/6/docs/technotes/guides/secu‐
rity/p11guide.html#keytooljarsigner section of the Java PKCS#11 Ref‐
erence Guide for details.
Supported Algorithms
By default, jarsigner signs a JAR file using either
o DSA (Digital Signature Algorithm) with the SHA-1 digest algo‐
rithm, or
o the RSA algorithm with the MD5 digest algorithm.
That is, if the signer's public and private keys are DSA keys, jar‐
signer will sign the JAR file using the "SHA1withDSA" algorithm. If
the signer's keys are RSA keys, jarsigner will attempt to sign the
JAR file using the "MD5withRSA" algorithm.
These default signature algorithms can be overridden using the
-sigalg option.
The Signed JAR File
When jarsigner is used to sign a JAR file, the output signed JAR
file is exactly the same as the input JAR file, except that it has
two additional files placed in the META-INF directory:
o a signature file, with a .SF extension, and
o a signature block file, with a .DSA extension.
The base file names for these two files come from the value of the
-sigFile option. For example, if the option appears as
-sigFile MKSIGN
the files are named "MKSIGN.SF" and "MKSIGN.DSA".
If no -sigfile option appears on the command line, the base file
name for the .SF and .DSA files will be the first 8 characters of
the alias name specified on the command line, all converted to upper
case. If the alias name has fewer than 8 characters, the full alias
name is used. If the alias name contains any characters that are not
allowed in a signature file name, each such character is converted
to an underscore ("_") character in forming the file name. Legal
characters include letters, digits, underscores, and hyphens.
The Signature (.SF) File
A signature file (the .SF file) looks similar to the manifest
file that is always included in a JAR file when jarsigner is used
to sign the file. That is, for each source file included in the
JAR file, the .SF file has three lines, just as in the manifest
file, listing the following:
o the file name,
o the name of the digest algorithm used (SHA), and
o a SHA digest value.
In the manifest file, the SHA digest value for each source file
is the digest (hash) of the binary data in the source file. In
the .SF file, on the other hand, the digest value for a given
source file is the hash of the three lines in the manifest file
for the source file.
The signature file also, by default, includes a header containing
a hash of the whole manifest file. The presence of the header
enables verification optimization, as described in JAR File Veri‐
fication.
The Signature Block (.DSA) File
The .SF file is signed and the signature is placed in the .DSA
file. The .DSA file also contains, encoded inside it, the cer‐
tificate or certificate chain from the keystore which authenti‐
cates the public key corresponding to the private key used for
signing.
Signature Timestamp
As of the J2SE 5.0 release, the jarsigner tool can now generate and
store a signature timestamp when signing a JAR file. In addition,
jarsigner supports alternative signing mechanisms. This behavior is
optional and is controlled by the user at the time of signing
through these options:
o -tsa url
o -tsacert alias
o -altsigner class
o -altsignerpath classpathlist
Each of these options is detailed in the Options section below.
JAR File Verification
A successful JAR file verification occurs if the signature(s) are
valid, and none of the files that were in the JAR file when the sig‐
natures were generated have been changed since then. JAR file veri‐
fication involves the following steps:
1. Verify the signature of the .SF file itself.
That is, the verification ensures that the signature stored in
each signature block (.DSA) file was in fact generated using the
private key corresponding to the public key whose certificate (or
certificate chain) also appears in the .DSA file. It also ensures
that the signature is a valid signature of the corresponding sig‐
nature (.SF) file, and thus the .SF file has not been tampered
with.
2. Verify the digest listed in each entry in the .SF file with
each corresponding section in the manifest.
The .SF file by default includes a header containing a hash of
the entire manifest file. When the header is present, then the
verification can check to see whether or not the hash in the
header indeed matches the hash of the manifest file. If that is
the case, verification proceeds to the next step.
If that is not the case, a less optimized verification is
required to ensure that the hash in each source file information
section in the .SF file equals the hash of its corresponding sec‐
tion in the manifest file (see The Signature (.SF) File).
One reason the hash of the manifest file that is stored in the
.SF file header may not equal the hash of the current manifest
file would be because one or more files were added to the JAR
file (using the jar tool) after the signature (and thus the .SF
file) was generated. When the jar tool is used to add files, the
manifest file is changed (sections are added to it for the new
files), but the .SF file is not. A verification is still consid‐
ered successful if none of the files that were in the JAR file
when the signature was generated have been changed since then,
which is the case if the hashes in the non-header sections of the
.SF file equal the hashes of the corresponding sections in the
manifest file.
3. Read each file in the JAR file that has an entry in the .SF
file. While reading, compute the file's digest, and then com‐
pare the result with the digest for this file in the manifest
section. The digests should be the same, or verification
fails.
If any serious verification failures occur during the verification
process, the process is stopped and a security exception is thrown.
It is caught and displayed by jarsigner.
Multiple Signatures for a JAR File
A JAR file can be signed by multiple people simply by running the
jarsigner tool on the file multiple times, specifying the alias for
a different person each time, as in:
jarsigner myBundle.jar susan
jarsigner myBundle.jar kevin
When a JAR file is signed multiple times, there are multiple .SF and
.DSA files in the resulting JAR file, one pair for each signature.
Thus, in the example above, the output JAR file includes files with
the following names:
SUSAN.SF
SUSAN.DSA
KEVIN.SF
KEVIN.DSA
Note: It is also possible for a JAR file to have mixed signatures,
some generated by the JDK 1.1 javakey tool and others by jarsigner.
That is, jarsigner can be used to sign JAR files already previously
signed using javakey.
OPTIONS
The various jarsigner options are listed and described below. Note:
o All option names are preceded by a minus sign (-).
o The options may be provided in any order.
o Items in italics (option values) represent the actual values that
must be supplied.
o The -keystore, -storepass, -keypass, -sigfile, -sigalg,
-digestalg, and -signedjar options are only relevant when signing
a JAR file, not when verifying a signed JAR file. Similarly, an
alias is only specified on the command line when signing a JAR
file.
-keystore url
Specifies the URL that tells the keystore location. This defaults
to the file .keystore in the user's home directory, as determined
by the "user.home" system property.
A keystore is required when signing, so you must explicitly specify
one if the default keystore does not exist (or you want to use one
other than the default).
A keystore is not required when verifying, but if one is specified,
or the default exists, and the -verbose option was also specified,
additional information is output regarding whether or not any of the
certificates used to verify the JAR file are contained in that key‐
store.
Note: the -keystore argument can actually be a file name (and path)
specification rather than a URL, in which case it will be treated
the same as a "file:" URL. That is,
-keystore filePathAndName
is treated as equivalent to
-keystore file:filePathAndName
If the Sun PKCS#11 provider has been configured in the java.security
security properties file (located in the JRE's $JAVA_HOME/lib/secu‐
rity directory), then keytool and jarsigner can operate on the
PKCS#11 token by specifying these options:
o -keystore NONE
o -storetype PKCS11
For example, this command lists the contents of the configured
PKCS#11 token:
jarsigner -keystore NONE -storetype PKCS11 -list
-storetype storetype
Specifies the type of keystore to be instantiated. The default
keystore type is the one that is specified as the value of the
"keystore.type" property in the security properties file, which
is returned by the static getDefaultType method in java.secu‐
rity.KeyStore.
The PIN for a PCKS#11 token can also be specified using the
-storepass option. If none has been specified, keytool and jarsigner
will prompt for the token PIN. If the token has a protected authen‐
tication path (such as a dedicated PIN-pad or a biometric reader),
then the -protected option must be specified and no password options
can be specified.
-storepass password
Specifies the password which is required to access the keystore.
This is only needed when signing (not verifying) a JAR file. In
that case, if a -storepass option is not provided at the command
line, the user is prompted for the password.
Note: The password shouldn't be specified on the command line or in
a script unless it is for testing purposes, or you are on a secure
system. Also, when typing in a password at the password prompt, the
password is echoed (displayed exactly as typed), so be careful not
to type it in front of anyone.
-keypass password
Specifies the password used to protect the private key of the
keystore entry addressed by the alias specified on the command
line. The password is required when using jarsigner to sign a JAR
file. If no password is provided on the command line, and the
required password is different from the store password, the user
is prompted for it.
Note: The password shouldn't be specified on the command line or in
a script unless it is for testing purposes, or you are on a secure
system. Also, when typing in a password at the password prompt, the
password is echoed (displayed exactly as typed), so be careful not
to type it in front of anyone.
-sigfile file
Specifies the base file name to be used for the generated .SF and
.DSA files. For example, if file is "DUKESIGN", the generated .SF
and .DSA files will be named "DUKESIGN.SF" and "DUKESIGN.DSA",
and will be placed in the "META-INF" directory of the signed JAR
file.
The characters in file must come from the set "a-zA-Z0-9_-". That
is, only letters, numbers, underscore, and hyphen characters are
allowed. Note: All lowercase characters will be converted to upper‐
case for the .SF and .DSA file names.
If no -sigfile option appears on the command line, the base file
name for the .SF and .DSA files will be the first 8 characters of
the alias name specified on the command line, all converted to upper
case. If the alias name has fewer than 8 characters, the full alias
name is used. If the alias name contains any characters that are not
legal in a signature file name, each such character is converted to
an underscore ("_") character in forming the file name.
-sigalg algorithm
Specifies the name of the signature algorithm to use to sign the
JAR file.
See Appendix A @
http://java.sun.com/javase/6/docs/technotes/guides/secu‐
rity/crypto/CryptoSpec.html#appa of the Java Cryptography Archi‐
tecture for a list of standard signature algorithm names. This
algorithm must be compatible with the private key used to sign
the JAR file. If this option is not specified, SHA1withDSA or
MD5withRSA will be used depending on the type of private key.
There must either be a statically installed provider supplying an
implementation of the specified algorithm or the user must spec‐
ify one with the -providerClass option, otherwise the command
will not succeed.
-digestalg algorithm
Specifies the name of the message digest algorithm to use when
digesting the entries of a jar file.
See Appendix A @
http://java.sun.com/javase/6/docs/technotes/guides/secu‐
rity/crypto/CryptoSpec.html#appa of the Java Cryptography Archi‐
tecture for a list of standard message digest algorithm names. If
this option is not specified, SHA-1 will be used. There must
either be a statically installed provider supplying an implemen‐
tation of the specified algorithm or the user must specify one
with the -providerClass option, otherwise the command will not
succeed.
-signedjar file
Specifies the name to be used for the signed JAR file.
If no name is specified on the command line, the name used is the
same as the input JAR file name (the name of the JAR file to be
signed); in other words, that file is overwritten with the signed
JAR file.
-verify
If this appears on the command line, the specified JAR file will
be verified, not signed. If the verification is successful, "jar
verified" will be displayed. If you try to verify an unsigned JAR
file, or a JAR file signed with an unsupported algorithm (e.g.,
RSA when you don't have an RSA provider installed), the following
is displayed: "jar is unsigned. (signatures missing or not
parsable)"
It is possible to verify JAR files signed using either jarsigner or
the JDK 1.1 javakey tool, or both.
For further information on verification, see JAR File Verification.
-certs
If this appears on the command line, along with the -verify and
-verbose options, the output includes certificate information for
each signer of the JAR file. This information includes
o the name of the type of certificate (stored in the .DSA file)
that certifies the signer's public key
o if the certificate is an X.509 certificate (more specifically,
an instance of java.security.cert.X509Certificate): the distin‐
guished name of the signer
The keystore is also examined. If no keystore value is specified on
the command line, the default keystore file (if any) will be
checked. If the public key certificate for a signer matches an entry
in the keystore, then the following information will also be dis‐
played:
o in parentheses, the alias name for the keystore entry for that
signer. If the signer actually comes from a JDK 1.1 identity
database instead of from a keystore, the alias name will appear
in brackets instead of parentheses.
-verbose
If this appears on the command line, it indicates "verbose" mode,
which causes jarsigner to output extra information as to the
progress of the JAR signing or verification.
-internalsf
In the past, the .DSA (signature block) file generated when a JAR
file was signed used to include a complete encoded copy of the
.SF file (signature file) also generated. This behavior has been
changed. To reduce the overall size of the output JAR file, the
.DSA file by default doesn't contain a copy of the .SF file any‐
more. But if -internalsf appears on the command line, the old
behavior is utilized. This option is mainly useful for testing;
in practice, it should not be used, since doing so eliminates a
useful optimization.
-sectionsonly
If this appears on the command line, the .SF file (signature
file) generated when a JAR file is signed does not include a
header containing a hash of the whole manifest file. It just con‐
tains information and hashes related to each individual source
file included in the JAR file, as described in The Signature
(.SF) File .
By default, this header is added, as an optimization. When the
header is present, then whenever the JAR file is verified, the veri‐
fication can first check to see whether or not the hash in the
header indeed matches the hash of the whole manifest file. If so,
verification proceeds to the next step. If not, it is necessary to
do a less optimized verification that the hash in each source file
information section in the .SF file equals the hash of its corre‐
sponding section in the manifest file.
For further information, see JAR File Verification.
This option is mainly useful for testing; in practice, it should not
be used, since doing so eliminates a useful optimization.
-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.
-provider provider-class-name
Used to specify the name of cryptographic service provider's mas‐
ter class file when the service provider is not listed in the
security properties file, java.security.
Used in conjunction with the -providerArg ConfigFilePath option,
keytool and jarsigner will install the provider dynamically (where
ConfigFilePath is the path to the token configuration file). Here's
an example of a command to list a PKCS#11 keystore when the Sun
PKCS#11 provider has not been configured in the security properties
file.
jarsigner -keystore NONE -storetype PKCS11 \
-providerClass sun.security.pkcs11.SunPKCS11 \
-providerArg /foo/bar/token.config \
-list
-providerName providerName
If more than one provider has been configured in the java.secu‐
rity security properties file, you can use the -providerName
option to target a specific provider instance. The argument to
this option is the name of the provider.
For the Sun PKCS#11 provider, providerName is of the form
SunPKCS11-TokenName, where TokenName is the name suffix that the
provider instance has been configured with, as detailed in the con‐
figuration attributes table @
http://java.sun.com/javase/6/docs/technotes/guides/secu‐
rity/p11guide.html#KeyToolJarSigner#ATTRS. For example, the follow‐
ing command lists the contents of the PKCS#11 keystore provider
instance with name suffix SmartCard:
jarsigner -keystore NONE -storetype PKCS11 \
-providerName SunPKCS11-SmartCard \
-list
-Jjavaoption
Passes through the specified javaoption string directly to the
Java interpreter. (jarsigner is actually a "wrapper" around the
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.
-tsa url
If "-tsa http://example.tsa.url" appears on the command line when
signing a JAR file then a timestamp is generated for the signa‐
ture. The URL, http://example.tsa.url, identifies the location of
the Time Stamping Authority (TSA). It overrides any URL found via
the -tsacert option. The -tsa option does not require the TSA's
public key certificate to be present in the keystore.
To generate the timestamp, jarsigner communicates with the TSA using
the Time-Stamp Protocol (TSP) defined in RFC 3161 @
http://www.ietf.org/rfc/rfc3161.txt. If successful, the timestamp
token returned by the TSA is stored along with the signature in the
signature block file.
-tsacert alias
If "-tsacert alias" appears on the command line when signing a
JAR file then a timestamp is generated for the signature. The
alias identifies the TSA's public key certificate in the keystore
that is currently in effect. The entry's certificate is examined
for a Subject Information Access extension that contains a URL
identifying the location of the TSA.
The TSA's public key certificate must be present in the keystore
when using -tsacert.
-altsigner class
Specifies that an alternative signing mechanism be used. The
fully-qualified class name identifies a class file that extends
the com.sun.jarsigner.ContentSigner abstract class. The path to
this class file is defined by the -altsignerpath option. If the
-altsigner option is used, jarsigner uses the signing mechanism
provided by the specified class. Otherwise, jarsigner uses its
default signing mechanism.
For example, to use the signing mechanism provided by a class named
com.sun.sun.jarsigner.AuthSigner, use the jarsigner option "-alt‐
signer com.sun.jarsigner.AuthSigner"
-altsignerpath classpathlist
Specifies the path to the class file (the class file name is
specified with the -altsigner option described above) and any JAR
files it depends on. If the class file is in a JAR file, then
this specifies the path to that JAR file, as shown in the example
below.
An absolute path or a path relative to the current directory may be
specified. If classpathlist contains multiple paths or JAR files,
they should be separated with a colon (:) on Solaris and a
semi-colon (;) on Windows. This option is not necessary if the class
is already in the search path.
Example of specifying the path to a jar file that contains the class
file:
-altsignerpath /home/user/lib/authsigner.jar
Note that the JAR file name is included.
Example of specifying the path to the jar file that contains the
class file:
-altsignerpath /home/user/classes/com/sun/tools/jarsigner/
Note that the JAR file name is omitted.
EXAMPLES
Signing a JAR File
Suppose you have a JAR file named "bundle.jar" and you'd like to
sign it using the private key of the user whose keystore alias is
"jane" in the keystore named "mystore" in the "working" directory.
Suppose the keystore password is "myspass" and the password for
jane's private key is "j638klm". You can use the following to sign
the JAR file and name the signed JAR file "sbundle.jar":
jarsigner -keystore /working/mystore -storepass myspass
-keypass j638klm -signedjar sbundle.jar bundle.jar jane
Note that there is no -sigfile specified in the command above, so
the generated .SF and .DSA files to be placed in the signed JAR file
will have default names based on the alias name. That is, they will
be named JANE.SF and JANE.DSA.
If you want to be prompted for the store password and the private
key password, you could shorten the above command to
jarsigner -keystore /working/mystore
-signedjar sbundle.jar bundle.jar jane
If the keystore to be used is the default keystore (the one named
".keystore" in your home directory), you don't need to specify a
keystore, as in:
jarsigner -signedjar sbundle.jar bundle.jar jane
Finally, if you want the signed JAR file to simply overwrite the
input JAR file (bundle.jar), you don't need to specify a -signedjar
option:
jarsigner bundle.jar jane
Verifying a Signed JAR File
To verify a signed JAR file, that is, to verify that the signature
is valid and the JAR file has not been tampered with, use a command
such as the following:
jarsigner -verify sbundle.jar
If the verification is successful,
jar verified.
is displayed. Otherwise, an error message appears.
You can get more information if you use the -verbose option. A sam‐
ple use of jarsigner with the -verbose option is shown below, along
with sample output:
jarsigner -verify -verbose sbundle.jar
198 Fri Sep 26 16:14:06 PDT 1997 META-INF/MANIFEST.MF
199 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.SF
1013 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.DSA
smk 2752 Fri Sep 26 16:12:30 PDT 1997 AclEx.class
smk 849 Fri Sep 26 16:12:46 PDT 1997 test.class
s = signature was verified
m = entry is listed in manifest
k = at least one certificate was found in keystore
jar verified.
Verification with Certificate Information
If you specify the -certs option when verifying, along with the -verify
and -verbose options, the output includes certificate information for
each signer of the JAR file, including the certificate type, the signer
distinguished name information (iff it's an X.509 certificate), and, in
parentheses, the keystore alias for the signer if the public key cer‐
tificate in the JAR file matches that in a keystore entry. For example,
jarsigner -keystore /working/mystore -verify -verbose -certs myTest.jar
198 Fri Sep 26 16:14:06 PDT 1997 META-INF/MANIFEST.MF
199 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.SF
1013 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.DSA
208 Fri Sep 26 16:23:30 PDT 1997 META-INF/JAVATEST.SF
1087 Fri Sep 26 16:23:30 PDT 1997 META-INF/JAVATEST.DSA
smk 2752 Fri Sep 26 16:12:30 PDT 1997 Tst.class
X.509, CN=Test Group, OU=Java Software, O=Sun Microsystems, L=CUP, S=CA, C=US (javatest)
X.509, CN=Jane Smith, OU=Java Software, O=Sun, L=cup, S=ca, C=us (jane)
s = signature was verified
m = entry is listed in manifest
k = at least one certificate was found in keystore
jar verified.
If the certificate for a signer is not an X.509 certificate, there is
no distinguished name information. In that case, just the certificate
type and the alias are shown. For example, if the certificate is a PGP
certificate, and the alias is "bob", you'd get
PGP, (bob)
Verification of a JAR File that Includes Identity Database Signers
If a JAR file has been signed using the JDK 1.1 javakey tool, and thus
the signer is an alias in an identity database, the verification output
includes an "i" symbol. If the JAR file has been signed by both an
alias in an identity database and an alias in a keystore, both "k" and
"i" appear.
When the -certs option is used, any identity database aliases are shown
in square brackets rather than the parentheses used for keystore
aliases. For example:
jarsigner -keystore /working/mystore -verify -verbose -certs writeFile.jar
198 Fri Sep 26 16:14:06 PDT 1997 META-INF/MANIFEST.MF
199 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.SF
1013 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.DSA
199 Fri Sep 27 12:22:30 PDT 1997 META-INF/DUKE.SF
1013 Fri Sep 27 12:22:30 PDT 1997 META-INF/DUKE.DSA
smki 2752 Fri Sep 26 16:12:30 PDT 1997 writeFile.html
X.509, CN=Jane Smith, OU=Java Software, O=Sun, L=cup, S=ca, C=us (jane)
X.509, CN=Duke, OU=Java Software, O=Sun, L=cup, S=ca, C=us [duke]
s = signature was verified
m = entry is listed in manifest
k = at least one certificate was found in keystore
i = at least one certificate was found in identity scope
jar verified.
Note that the alias "duke" is in brackets to denote that it is an iden‐
tity database alias, not a keystore alias.
SEE ALSO
o jar tool documentation
o keytool tool documentation
o the Security @
http://java.sun.com/docs/books/tutorial/security1.2/index.html
trail of the Java Tutorial @
http://java.sun.com/docs/books/tutorial/trailmap.html for examples
of the use of the jarsigner tool
07 Aug 2006 jarsigner(1)
Monday, January 24, 2011
jarsigner
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