jarsigner(1) Security Tools jarsigner(1)NAMEjarsigner - Signs and verifies Java Archive (JAR) files.
SYNOPSISjarsigner [ options ] jar-file alias
jarsigner-verify [ options ] jar-file [alias ...]
options
The command-line options. See Options.
-verify
The -verify option can take zero or more keystore alias names
after the JAR file name. When the -verify option is specified,
the jarsigner command checks 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.
If you also specified the -strict option, and the jarsigner
command detected severe warnings, the message, "jar verified,
with signer errors" is displayed.
jar-file
The JAR file to be signed.
If you also specified the -strict option, and the jarsigner
command detected severe warnings, the message, "jar signed, with
signer errors" is displayed.
alias The aliases are defined in the keystore specified by -keystore
or the default keystore.
DESCRIPTION
The jarsigner tool has two purposes:
· To sign Java Archive (JAR) files.
· 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
distribution. A tool named jar enables developers to produce JAR files.
(Technically, any zip file can also be considered a JAR file, although
when created by the jar command or processed by the jarsigner command,
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, and so on). Similar to a handwritten signature, a digital
signature has many useful characteristics:
· Its authenticity can be verified by a computation that uses the
public key corresponding to the private key used to generate the
signature.
· It cannot be forged, assuming the private key is kept secret.
· It is a function of the data signed and thus cannot be claimed to be
the signature for other data as well.
· The signed data cannot be changed. If the data is changed, then the
signature cannot be verified as authentic.
To generate an entity's signature for a file, the entity must first
have a public/private key pair associated with it and one or more
certificates that authenticate its public key. A certificate is a
digitally signed statement from one entity that says that the public
key of another entity has a particular value.
The jarsigner command uses key and certificate information from a
keystore to generate digital signatures for JAR files. A keystore is a
database of private keys and their associated X.509 certificate chains
that authenticate the corresponding public keys. The keytool command is
used to create and administer keystores.
The jarsigner command 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. The jarsigner command can verify
the digital signature of the signed JAR file using the certificate
inside it (in its signature block file).
The jarsigner command can generate signatures that include a time stamp
that lets a systems or deployer (including Java Plug-in) to check
whether the JAR file was signed while the signing certificate was still
valid. In addition, APIs allow applications to obtain the timestamp
information.
At this time, the jarsigner command can only sign JAR files created by
the jar command or zip files. JAR files are the same as zip files,
except they also have a META-INF/MANIFEST.MF file. A META-
INF/MANIFEST.MF file is created when the jarsigner command signs a zip
file.
The default jarsigner command behavior is to sign a JAR or zip file.
Use the -verify option to verify a signed JAR file.
The jarsigner command also attempts to validate the signer's
certificate after signing or verifying. If there is a validation error
or any other problem, the command generates warning messages. If you
specify the -strict option, then the command treats severe warnings as
errors. See Errors and Warnings.
KEYSTORE ALIASES
All keystore entities are accessed with unique aliases.
When you use the jarsigner command to sign a JAR file, you must specify
the alias for the keystore entry that contains the private key needed
to generate the signature. For example, the following command signs the
JAR file named MyJARFile.jar with the private key associated with the
alias duke in the keystore named mystore in the working directory.
Because 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 are prompted for it when you do not 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
are prompted for the password when you do not specify it on the command
line and it is not the same as the store password.
KEYSTORE LOCATION
The jarsigner command 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 Oracle Solaris systems, user.home defaults to the user's home
directory.
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
when the KeyStore class is not file based, for example, when it resides
on a hardware token device.
KEYSTORE IMPLEMENTATION
The KeyStore class provided in the java.security package supplies a
number of well-defined interfaces to access and modify the information
in a keystore. You can have multiple different concrete
implementations, where each implementation is for a particular type of
keystore.
Currently, there are two command-line tools that use keystore
implementations (keytool and jarsigner), and a GUI-based tool named
Policy Tool. Because the KeyStore class is publicly available, JDK
users can write additional security applications that use it.
There is a built-in default implementation provided by Oracle that
implements the keystore as a file, that uses a proprietary keystore
type (format) named JKS. The built-in implementation protects each
private key with its individual password and protects the integrity of
the entire keystore with a (possibly different) password.
Keystore implementations are provider-based, which means the
application interfaces supplied by the KeyStore class are implemented
in terms of a Service Provider Interface (SPI). There is a
corresponding abstract KeystoreSpi class, also in the java.security
package, that 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. To provide a
keystore implementation, clients must implement a provider and supply a
KeystoreSpi subclass implementation, as described in How to Implement a
Provider in the Java Cryptography Architecture at
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/HowToImplAProvider.html
Applications can choose different types of keystore implementations
from different providers, with the getInstance factory method 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.
The jarsigner and policytool commands can read file-based keystores
from any location that can be specified using a URL. In addition, these
commands can read non-file-based keystores such as those provided by
MSCAPI on Windows and PKCS11 on all platforms.
For the jarsigner and keytool commands, you can specify a keystore type
at the command line with the -storetype option. For Policy Tool, you
can specify a keystore type with the Edit command in the KeyStore menu.
If you do not explicitly specify a keystore type, then the tools choose
a keystore implementation based 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 JDK
security properties directory, java.home/lib/security, where java.home
is the runtime environment's directory. The jre directory in the JDK or
the top-level directory of the Java Runtime Environment (JRE).
Each tool gets the keystore.type value and then examines all the
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
Case does not matter in keystore type designations. For example, JKS is
the same as jks.
To have the tools use 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, then change the line to the following:
keystore.type=pkcs12
Note: If you use the PKCS 11 provider package, then see "KeyTool" and
"JarSigner" in Java PKCS #11 Reference Guide at
http://docs.oracle.com/javase/7/docs/technotes/guides/security/p11guide.html
SUPPORTED ALGORITHMS
By default, the jarsigner command signs a JAR file using one of the
following algorithms:
· Digital Signature Algorithm (DSA) with the SHA1 digest algorithm
· RSA algorithm with the SHA256 digest algorithm
· Elliptic Curve (EC) cryptography algorithm with the SHA256 with
Elliptic Curve Digital Signature Algorithm (ECDSA).
If the signer's public and private keys are DSA keys, then jarsigner
signs the JAR file with the SHA1withDSA algorithm. If the signer's keys
are RSA keys, then jarsigner attempts to sign the JAR file with the
SHA256withRSA algorithm. If the signer's keys are EC keys, then
jarsigner signs the JAR file with the SHA256withECDSA algorithm.
These default signature algorithms can be overridden using the -sigalg
option.
THE SIGNED JAR FILE
When the jarsigner command 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:
· A signature file with an .SF extension
· 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, when the option is -sigFile MKSIGN, the
files are named MKSIGN.SF and MKSIGN.DSA
If no -sigfile option appears on the command line, then the base file
name for the .SF and .DSA files is the first 8 characters of the alias
name specified on the command line, all converted to uppercase. If the
alias name has fewer than 8 characters, then the full alias name is
used. If the alias name contains any characters that are not allowed in
a signature file name, then each such character is converted to an
underscore (_) character in forming the file name. Valid characters
include letters, digits, underscores, and hyphens.
Signature File
A signature file (.SF file) looks similar to the manifest file that is
always included in a JAR file when the jarsigner command is used to
sign the file. For each source file included in the JAR file, the .SF
file has three lines, such as in the manifest file, that list the
following:
· File name
· Name of the digest algorithm (SHA)
· 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,
the digest value for a specified source file is the hash of the three
lines in the manifest file for the source file.
The signature file, by default, includes a header with a hash of the
whole manifest file. The header also contains a hash of the manifest
header. The presence of the header enables verification optimization.
See JAR File Verification.
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 that 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 TIME STAMP
The jarsigner command can generate and store a signature time stamp
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. See Options.
-tsa url
-tsacert alias
-altsigner class
-altsignerpath classpathlist
-tsapolicyid policyid
JAR FILE VERIFICATION
A successful JAR file verification occurs when the signatures are
valid, and none of the files that were in the JAR file when the
signatures were generated have changed since then. JAR file
verification involves the following steps:
1. Verify the signature of the .SF file.
The verification ensures that the signature stored in each
signature block (.DSA) file was 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 signature (.SF)
file, and thus the .SF file was not 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 that contains a hash of
the entire manifest file. When the header is present, the
verification can check to see whether or not the hash in the header
matches the hash of the manifest file. If there is a match, then
verification proceeds to the next step.
If there is no match, then 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
section in the manifest file. See Signature File.
One reason the hash of the manifest file that is stored in the .SF
file header might not equal the hash of the current manifest file
is that one or more files were added to the JAR file (with the jar
tool) after the signature and .SF file were generated. When the jar
tool is used to add files, the manifest file is changed by adding
sections to it for the new files, but the .SF file is not changed.
A verification is still considered successful when none of the
files that were in the JAR file when the signature was generated
have been changed since then. This happens when 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 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, then the process is stopped and a security exception is
thrown. The jarsigner command catches and displays the exception.
Note: You should read any addition warnings (or errors if you specified
the -strict option), as well as the content of the certificate (by
specifying the -verbose and -certs options) to determine if the
signature can be trusted.
MULTIPLE SIGNATURES FOR A JAR FILE
A JAR file can be signed by multiple people by running the jarsigner
command on the file multiple times and specifying the alias for a
different person each time, as follows:
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. In
the previous example, 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 by the javakey command and others by
jarsigner. The jarsigner command can be used to sign JAR files that are
already signed with the javakey command.
OPTIONS
The following sections describe the various jarsigner options. Be aware
of the following standards:
· All option names are preceded by a minus sign (-).
· The options can be provided in any order.
· Items that are in italics or underlined (option values) represent the
actual values that must be supplied.
· The -storepass, -keypass, -sigfile, -sigalg, -digestalg, -signedjar,
and TSA-related options are only relevant when signing a JAR file;
they are not relevant when verifying a signed JAR file. The -keystore
option is relevant for signing and verifying a JAR file. In addition,
aliases are specified when signing and verifying 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. You must explicitly specify a
keystore when the default keystore does not exist or if 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, then
additional information is output regarding whether or not any of the
certificates used to verify the JAR file are contained in that
keystore.
The -keystore argument can be a file name and path specification
rather than a URL, in which case it is treated the same as a file:
URL, for example, the following are equivalent:
-keystore filePathAndName
-keystore file:filePathAndName
If the Sun PKCS #11 provider was configured in the java.security
security properties file (located in the JRE's
$JAVA_HOME/lib/security directory), then the keytool and jarsigner
tools can operate on the PKCS #11 token by specifying these options:
-keystore NONE
-storetype PKCS11
For example, the following command lists the contents of the
configured PKCS#11 token:
keytool -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.security.KeyStore.
The PIN for a PCKS #11 token can also be specified with the
-storepass option. If none is specified, then the keytool and
jarsigner commands prompt for the token PIN. If the token has a
protected authentication 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[:env | :file] argument
Specifies the password that 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, then 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:
· env: Retrieve the password from the environment variable named
argument.
· file: Retrieve the password from the file named argument.
Note: The password should not 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, then 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:
· env: Retrieve the password from the environment variable named
argument.
· file: Retrieve the password from the file named argument.
Note: The password should not 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, then the generated .SF
and .DSA files are named DUKESIGN.SF and DUKESIGN.DSA, and placed in
the META-INF directory of the signed JAR file.
The characters in the file must come from the set a-zA-Z0-9_-. Only
letters, numbers, underscore, and hyphen characters are allowed. All
lowercase characters are converted to uppercase for the .SF and .DSA
file names.
If no -sigfile option appears on the command line, then the base file
name for the .SF and .DSA files is 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, then the full
alias name is used. If the alias name contains any characters that
are not valid in a signature file name, then each such character is
converted to an underscore (_) character to form the file name.
-sigalg algorithm
Specifies the name of the signature algorithm to use to sign the JAR
file.
For a list of standard signature algorithm names, see "Appendix A:
Standard Names" in the Java Cryptography Architecture (JCA) Reference
Guide at
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/CryptoSpec.html#AppA
This algorithm must be compatible with the private key used to sign
the JAR file. If this option is not specified, then SHA1withDSA,
SHA256withRSA, or SHA256withECDSA are 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; 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.
For a list of standard message digest algorithm names, see "Appendix
A: Standard Names" in the Java Cryptography Architecture (JCA)
Reference Guide at
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/CryptoSpec.html#AppA
If this option is not specified, then SHA256 is used. 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; otherwise, the command will not succeed.
-certs
If the -certs option appears on the command line with the -verify and
-verbose options, then the output includes certificate information
for each signer of the JAR file. This information includes the name
of the type of certificate (stored in the .DSA file) that certifies
the signer's public key, and if the certificate is an X.509
certificate (an instance of the java.security.cert.X509Certificate),
then the distinguished name of the signer.
The keystore is also examined. If no keystore value is specified on
the command line, then the default keystore file (if any) is checked.
If the public key certificate for a signer matches an entry in the
keystore, then the alias name for the keystore entry for that signer
is displayed in parentheses. If the signer comes from a JDK 1.1
identity database instead of from a keystore, then the alias name
displays in brackets instead of parentheses.
-certchain file
Specifies the certificate chain to be used when the certificate chain
associated with the private key of the keystore entry that is
addressed by the alias specified on the command line is not complete.
This can happen when the keystore is located on a hardware token
where there is not enough capacity to hold a complete certificate
chain. The file can be a sequence of concatenated X.509 certificates,
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. See the
section Internet RFC 1421 Certificate Encoding Standard in keytool
and http://tools.ietf.org/html/rfc1421.
-verbose
When the -verbose option appears on the command line, it indicates
verbose mode, which causes jarsigner to output extra information
about the progress of the JAR signing or verification.
-internalsf
In the past, the .DSA (signature block) file generated when a JAR
file was signed included 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 does not contain a copy of the .SF file anymore. If
-internalsf appears on the command line, then the old behavior is
utilized. This option is useful for testing. In practice, do not use
the -internalsf option because it incurs higher overhead.
-sectionsonly
If the -sectionsonly option appears on the command line, then the .SF
file (signature file) generated when a JAR file is signed does not
include a header that contains a hash of the whole manifest file. It
contains only the information and hashes related to each individual
source file included in the JAR file. See Signature File.
By default, this header is added, as an optimization. When the header
is present, whenever the JAR file is verified, the verification can
first check to see whether the hash in the header matches the hash of
the whole manifest file. When there is a match, verification proceeds
to the next step. When there is no match, 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
corresponding section in the manifest file. See JAR File
Verification.
The -sectionsonly option is primarily used for testing. It should not
be used other than for testing because using it incurs higher
overhead.
-protected
Values can be either true or false. Specify true when a password must
be specified through a protected authentication path such as a
dedicated PIN reader.
-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
java.security security properties file.
Used with the -providerArg ConfigFilePath option, the keytool and
jarsigner tools install the provider dynamically and use
ConfigFilePath for the path to the token configuration file. The
following example shows a command to list a PKCS #11 keystore when
the Oracle PKCS #11 provider was not configured in the security
properties file.
jarsigner-keystore NONE -storetype PKCS11 \
-providerClass sun.security.pkcs11.SunPKCS11 \
-providerArg /mydir1/mydir2/token.config \
-list
-providerName providerName
If more than one provider was configured in the java.security
security properties file, then 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 Oracle 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. 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. The jarsigner command is 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 time stamp is generated for the signature.
The URL, http://example.tsa.url, identifies the location of the Time
Stamping Authority (TSA) and overrides any URL found with the
-tsacert option. The -tsa option does not require the TSA public key
certificate to be present in the keystore.
To generate the time stamp, jarsigner communicates with the TSA with
the Time-Stamp Protocol (TSP) defined in RFC 3161. When successful,
the time stamp token returned by the TSA is stored with the signature
in the signature block file.
-tsacert alias
When -tsacert alias appears on the command line when signing a JAR
file, a time stamp is generated for the signature. The alias
identifies the TSA public key certificate in the keystore that is 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 public key certificate must be present in the keystore when
using the -tsacert option.
-tsapolicyid policyid
Specifies the object identifier (OID) that identifies the policy ID
to be sent to the TSA server. If this option is not specified, no
policy ID is sent and the TSA server will choose a default policy ID.
Object identifiers are defined by X.696, which is an ITU
Telecommunication Standardization Sector (ITU-T) standard. These
identifiers are typically period-separated sets of non-negative
digits like 1.2.3.4, for example.
-altsigner class
This option specifies an alternative signing mechanism. 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, then the jarsigner command uses the signing mechanism
provided by the specified class. Otherwise, the jarsigner command
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 and any JAR file it depends on.
The class file name is specified with the -altsigner option. If the
class file is in a JAR file, then this option specifies the path to
that JAR file.
An absolute path or a path relative to the current directory can be
specified. If classpathlist contains multiple paths or JAR files,
then they should be separated with a colon (:) on Oracle Solaris and
a semicolon (;) on Windows. This option is not necessary when the
class is already in the search path.
The following example shows how to specify the path to a JAR file
that contains the class file. The JAR file name is included.
-altsignerpath /home/user/lib/authsigner.jar
The following example shows how to specify the path to the JAR file
that contains the class file. The JAR file name is omitted.
-altsignerpath /home/user/classes/com/sun/tools/jarsigner/
-strict
During the signing or verifying process, the command may issue
warning messages. If you specify this option, the exit code of the
tool reflects the severe warning messages that this command found.
See Errors and Warnings.
-verbose suboptions
For the verifying process, the -verbose option takes suboptions to
determine how much information is shown. If the -certs option is also
specified, then the default mode (or suboption all) displays each
entry as it is being processed, and after that, the certificate
information for each signer of the JAR file. If the -certs and the
-verbose:grouped suboptions are specified, then entries with the same
signer info are grouped and displayed together with their certificate
information. If -certs and the -verbose:summary suboptions are
specified, then entries with the same signer information are grouped
and displayed together with their certificate information. Details
about each entry are summarized and displayed as one entry (and
more). See Examples.
ERRORS AND WARNINGS
During the signing or verifying process, the jarsigner command may
issue various errors or warnings.
If there is a failure, the jarsigner command exits with code 1. If
there is no failure, but there are one or more severe warnings, the
jarsigner command exits with code 0 when the -strict option is not
specified, or exits with the OR-value of the warning codes when the
-strict is specified. If there is only informational warnings or no
warning at all, the command always exits with code 0.
For example, if a certificate used to sign an entry is expired and has
a KeyUsage extension that does not allow it to sign a file, the
jarsigner command exits with code 12 (=4+8) when the -strict option is
specified.
Note: Exit codes are reused because only the values from 0 to 255 are
legal on Unix-based operating systems.
The following sections describes the names, codes, and descriptions of
the errors and warnings that the jarsigner command can issue.
FAILURE
Reasons why the jarsigner command fails include (but are not limited
to) a command line parsing error, the inability to find a keypair to
sign the JAR file, or the verification of a signed JAR fails.
failure
Code 1. The signing or verifying fails.
SEVERE WARNINGS
Note: Severe warnings are reported as errors if you specify the -strict
option.
Reasons why the jarsigner command issues a severe warning include the
certificate used to sign the JAR file has an error or the signed JAR
file has other problems.
hasExpiredCert
Code 4. This jar contains entries whose signer certificate has
expired.
notYetValidCert
Code 4. This jar contains entries whose signer certificate is
not yet valid.
chainNotValidated
Code 4. This jar contains entries whose certificate chain cannot
be correctly validated.
badKeyUsage
Code 8. This jar contains entries whose signer certificate's
KeyUsage extension doesn't allow code signing.
badExtendedKeyUsage
Code 8. This jar contains entries whose signer certificate's
ExtendedKeyUsage extension doesn't allow code signing.
badNetscapeCertType
Code 8. This jar contains entries whose signer certificate's
NetscapeCertType extension doesn't allow code signing.
hasUnsignedEntry
Code 16. This jar contains unsigned entries which have not been
integrity-checked.
notSignedByAlias
Code 32. This jar contains signed entries which are not signed
by the specified alias(es).
aliasNotInStore
Code 32. This jar contains signed entries that are not signed by
alias in this keystore.
INFORMATIONAL WARNINGS
Informational warnings include those that are not errors but regarded
as bad practice. They do not have a code.
hasExpiringCert
This jar contains entries whose signer certificate will expire
within six months.
noTimestamp
This jar contains signatures that does not include a timestamp.
Without a timestamp, users may not be able to validate this JAR
file after the signer certificate's expiration date (YYYY-MM-DD)
or after any future revocation date.
EXAMPLES
SIGN A JAR FILE
Use the following command to sign bundle.jar with the private key of a
user whose keystore alias is jane in a keystore named mystore in the
working directory and name the signed JAR file sbundle.jar:
jarsigner-keystore /working/mystore
-storepass <keystore password>
-keypass <private key password>
-signedjar sbundle.jar bundle.jar jane
There is no -sigfile specified in the previous command so the generated
.SF and .DSA files to be placed in the signed JAR file have default
names based on the alias name. They are named JANE.SF and JANE.DSA.
If you want to be prompted for the store password and the private key
password, then you could shorten the previous command to the following:
jarsigner-keystore /working/mystore
-signedjar sbundle.jar bundle.jar jane
If the keystore is the default keystore (.keystore in your home
directory), then you do not need to specify a keystore, as follows:
jarsigner-signedjar sbundle.jar bundle.jar jane
If you want the signed JAR file to overwrite the input JAR file
(bundle.jar), then you do not need to specify a -signedjar option, as
follows:
jarsigner bundle.jar jane
VERIFY A SIGNED JAR FILE
To verify a signed JAR file to ensure that the signature is valid and
the JAR file was not been tampered with, use a command such as the
following:
jarsigner-verify sbundle.jar
When the verification is successful, jar verified is displayed.
Otherwise, an error message is displayed. You can get more information
when you use the -verbose option. A sample use of jarsigner with the-
verbose option follows:
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 with the -verify and -verbose options,
then the output includes certificate information for each signer of the
JAR file. The information includes the certificate type, the signer
distinguished name information (when it is an X.509 certificate), and
in parentheses, the keystore alias for the signer when the public key
certificate in the JAR file matches the one 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=Oracle, L=CUP, S=CA, C=US (javatest)
X.509, CN=Jane Smith, OU=Java Software, O=Oracle, 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, then 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, then you would
get: PGP, (bob).
VERIFICATION THAT INCLUDES IDENTITY DATABASE SIGNERS
If a JAR file was signed with the JDK 1.1 javakey tool, and the signer
is an alias in an identity database, then the verification output
includes an i. If the JAR file was signed by both an alias in an
identity database and an alias in a keystore, then both k and i appear.
When the -certs option is used, any identity database aliases are shown
in 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=Oracle, L=cup, S=ca, C=us (jane)
X.509, CN=Duke, OU=Java Software, O=Oracle, 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: The alias duke is in brackets to denote that it is an identity
database alias, and not a keystore alias.
JDK 1.1 COMPATIBILITY
The keytool and jarsigner tools replace the javakey tool 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 backward compatibility between
the keystore format and the database format used by javakey in JDK 1.1.
However, be aware of the following:
· It is possible to import the information from an identity database
into a keystore through the keytool -identitydb command.
· The jarsigner command can sign JAR files that were signed with the
javakey command.
· The jarsigner command can verify JAR files signed with javakey. The
jarsigner command recognizes and can work with signer aliases that
are from a JDK 1.1 identity database rather than a JDK keystore.
UNSIGNED JARS
Unsigned JARs have the default privileges that are granted to all code.
SIGNED JARS
Signed JARs have the privilege configurations based on their JDK 1.1.n
identity and policy file status as described. Only trusted identities
can be imported into the JDK keystore.
Default Privileges Granted to All Code
Identity in 1.1 database: No
Trusted identity imported into Java keystore from 1.1. database: No
Policy file grants privileges to identity/alias: No
Identity in 1.1 database: No
Trusted identity imported into Java keystore from 1.1. database: Yes
Policy file grants privileges to identity/alias: No
Identity in 1.1 database: Yes/Untrusted
Trusted identity imported into Java keystore from 1.1. database: No
Policy file grants privileges to identity/alias: No
See 3 in Notes Regarding Privileges of Signed JARs.
Identity in 1.1 database: Yes/Untrusted
Trusted identity imported into Java keystore from 1.1. database: No
Policy file grants privileges to identity/alias: Yes
See 1 and 3 in Notes Regarding Privileges of Signed JARs.
Default Privileges and Policy File Privileges Granted
Identity in 1.1 database: No
Trusted identity imported into Java keystore from 1.1. database: Yes
Policy file grants privileges to identity/alias: Yes
Identity in 1.1 database: Yes/Trusted
Trusted identity imported into Java keystore from 1.1. database: Yes
Policy file grants privileges to identity/alias: Yes
See 2 in Notes Regarding Privileges of Signed JARs.
All Privileges Granted
Identity in 1.1 database: Yes/Trusted
Trusted identity imported into Java keystore from 1.1. database: No
Policy file grants privileges to identity/alias: No
Identity in 1.1 database: Yes/Trusted
Trusted identity imported into Java keystore from 1.1. database: Yes
Policy file grants privileges to identity/alias: No
See 1 in Notes Regarding Privileges of Signed JARs.
Identity in 1.1 database: Yes/Trusted
Trusted identity imported into Java keystore from 1.1. database: No
Policy file grants privileges to identity/alias: Yes
See 1 in Notes Regarding Privileges of Signed JARs.
Notes Regarding Privileges of Signed JARs
1. If an identity or alias is mentioned in the policy file, then 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 platform.
SEE ALSO
· jar
· keytool
· Trail: Security Features in Java SE at
http://docs.oracle.com/javase/tutorial/security/index.html
JDK 7 6 August 2013 jarsigner(1)
