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 [alias...]
The jarsigner -verify command can take zero or more keystore alias
names after the jar filename. When specified, jarsigner will check that
the certificate used to verify each signed entry in the jar file
matches one of the keystore aliases. The aliases are defined in the
keystore specified by -keystore, or the default keystore.
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(1) enables developers to produce JAR files.
(Technically, 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(1) utility is used to
create 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).
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 will allow applications to obtain the timestamp informa‐
tion.
At this time, jarsigner can only sign JAR files created by the SDK
jar(1) 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 automati‐
cally 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.
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" directory. Since no
output file is specified, it overwrites MyJARFile.jar with the signed
JAR file.
jarsigner -keystore /working/mystore -storepass <keystore password>
-keypass <private key password> MyJARFile.jar duke
Keystores are protected with a password, so the store password 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 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 keystore
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 key‐
store. 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 keystore
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 Microsys‐
tems. 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 pack‐
ages 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 Key‐
storeSpi subclass implementation, as described in How to Implement a
Provider for the Java Cryptography Architecture @
http://docs.oracle.com/javase/7/docs/technotes/guides/secu‐
rity/crypto/HowToImplAProvider.html.
Applications can choose different types of keystore implementations
from different providers, using the "getInstance" factory method sup‐
plied 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
keystore location that is passed to it at the command line as a file‐
name and converts it to a FileInputStream, from which it loads the key‐
store 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 com‐
mand 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 keystore.type
property specified in the security properties file. The security prop‐
erties 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 Environment).
Each tool gets the keystore.type value and then examines all the cur‐
rently-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 key‐
store implementation provided by Sun). This is specified by the follow‐
ing line in the security properties file:
keystore.type=jks
Note: Case doesn't matter in keystore type designations. For example,
"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 imple‐
mentation 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://docs.oracle.com/javase/7/docs/technotes/guides/secu‐
rity/p11guide.html#KeyToolJarSigner section of the Java PKCS#11 Refer‐
ence Guide for details.
Supported Algorithms
By default, jarsigner signs a JAR file using one of the following:
o DSA (Digital Signature Algorithm) with the SHA1 digest algorithm
o RSA algorithm with the SHA256 digest algorithm.
o EC (Elliptic Curve) cryptography algorithm with the SHA256 with
ECDSA (Elliptic Curve Digital Signature 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 "SHA256withRSA" algorithm. If the signer's keys are EC keys,
jarsigner will sign the JAR file using the "SHA256withECDSA" 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 addi‐
tional files placed in the META-INF directory:
o a signature file, with a .SF extension, and
o a signature block file, with a .DSA, .RSA, or .EC 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 signa‐
ture 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 follow‐
ing:
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 Verification.
The Signature Block File
The .SF file is signed and the signature is placed in the signature
block file. This file also contains, encoded inside it, the certificate
or certificate chain from the keystore which authenticates the public
key corresponding to the private key used for signing. The file has the
extension .DSA, .RSA, or .EC depending on the digest algorithm used.
Signature Timestamp
jarsigner tool can generate and store a signature timestamp when sign‐
ing 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 signa‐
tures were generated have been changed since then. JAR file verifica‐
tion 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 compare 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 jar‐
signer tool on the file multiple times, specifying the alias for a dif‐
ferent 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 spec‐
ify 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 speci‐
fied, 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 con‐
tained in that keystore.
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.secu‐
rity security properties file (located in the JRE's
$JAVA_HOME/lib/security 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 jar‐
signer will prompt for the token PIN. If the token has a pro‐
tected authentication path (such as a dedicated PIN-pad or a bio‐
metric reader), then the -protected option must be specified and
no password options can be specified.
-storepass[:env | :file] argument
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.
If the modifier env or file is not specified, then the password
has the value argument. 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: 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.
-keypass[:env | :file] argument
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.
If the modifier env or file is not specified, then the password
has the value argument. 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: 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.
-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
uppercase 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 charac‐
ters that are not legal in a signature file name, each such char‐
acter 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://docs.oracle.com/javase/7/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,
SHA256withRSA, or SHA256withECDSA 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 specify one with the -providerClass option, oth‐
erwise 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://docs.oracle.com/javase/7/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, SHA256 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 Verifica‐
tion.
-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.
-certchain file
Specifies the certificate chain to be used, if the certificate
chain associated with the private key of the keystore entry,
addressed by the alias specified on the command line, is not com‐
plete. This may happen if the keystore is located on a hardware
token where there is not enough capacity to hold a complete cer‐
tificate chain. The file can be a sequence of X.509 certificates
concatenated together, or a single PKCS#7 formatted data block,
either in binary encoding format or in printable encoding format
(also known as BASE64 encoding) as defined by the Internet RFC
1421 standard.
-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
verification 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 neces‐
sary to do a less optimized verification that the hash in each
source file information section in the .SF file equals the hash
of its corresponding 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.
-providerClass 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
configuration attributes table @
http://docs.oracle.com/javase/7/docs/technotes/guides/secu‐
rity/p11guide.html#ATTRS. For example, the following 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
"-altsigner 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.
-strict
During the signing or verifying process, some warning messages
may be shown. If this option appears on the command line, the
exit code of the tool will reflect the warning messages that are
found. Read the "WARNINGS" section for details.
-verbose:sub-options
For the verifying process, the -verbose option takes sub-options
to determine how much information will be shown. If -certs is
also specified, the default mode (or sub-option all) displays
each entry as it is being processed and following that, the cer‐
tificate information for each signer of the JAR file. If -certs
and the -verbose:grouped sub-option are specified, entries with
the same signer info are grouped and displayed together along
with their certificate information. If -certs and the -ver‐
bose:summary sub-option are specified, then entries with the same
signer info are grouped and displayed together along with their
certificate information but details about each entry are summa‐
rized and displayed as "one entry (and more)". See the examples
section for more information.
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. You can use
the following to sign the JAR file and name the signed JAR file "sbun‐
dle.jar":
jarsigner -keystore /working/mystore -storepass <keystore password>
-keypass <private key password> -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 key‐
store, 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 sample
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 (if and only if it's an X.509 certifi‐
cate), and, in parentheses, the keystore alias for the signer if the
public key certificate 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.
WARNINGS
During the signing/verifying process, jarsigner may display various
warnings. These warning codes are defined as follows:
hasExpiringCert 2
This jar contains entries whose signer certificate will expire within six months
hasExpiredCert 4
This jar contains entries whose signer certificate has expired.
notYetValidCert 4
This jar contains entries whose signer certificate is not yet valid.
chainNotValidated 4
This jar contains entries whose certificate chain cannot be correctly validated.
badKeyUsage 8
This jar contains entries whose signer certificate's KeyUsage extension doesn't allow code signing.
badExtendedKeyUsage 8
This jar contains entries whose signer certificate's ExtendedKeyUsage extension
doesn't allow code signing.
badNetscapeCertType 8
This jar contains entries whose signer certificate's NetscapeCertType extension
doesn't allow code signing.
hasUnsignedEntry 16
This jar contains unsigned entries which have not been integrity-checked.
notSignedByAlias 32
This jar contains signed entries which are not signed by the specified alias(es)
aliasNotInStore 32
This jar contains signed entries that are not signed by alias in this keystore
When the -strict option is provided, an OR-value of warnings detected
will be returned as the exit code of the tool. For example, if a cer‐
tificate used to sign an entry is expired and has a keyUsage extension
that does not allow it to sign a file, an exit code 12 (=4+8) will be
returned.
Note: Exit codes are reused because only 0-255 is legal for Unix. In
any case, if the signing/verifying process fails, the following exit
code will be returned:
failure 1
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 addition 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 database
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 rec‐
ognizes 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.
SEE ALSO
o jar(1) tool documentation
o keytool(1) 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/index.html for examples of
the use of the jarsigner tool
16 Mar 2012 jarsigner(1)
