java.security
Class Signature

java.lang.Object
  |
  +--java.security.SignatureSpi
        |
        +--java.security.Signature

Direct Known Subclasses:

java.security.Signature.Delegate

public abstract class Signature

extends SignatureSpi

Untamed:

Field Summary

private String	algorithm
private static boolean	debug
private Provider	provider
protected static int	SIGN Possible state value, signifying that this signature object has been initialized for signing.
protected int	state Current state of this signature object.
protected static int	UNINITIALIZED Possible state value, signifying that this signature object has not yet been initialized.
protected static int	VERIFY Possible state value, signifying that this signature object has been initialized for verification.

Fields inherited from class java.security.SignatureSpi

appRandom

Constructor Summary

protected

Signature(String algorithm) Creates a Signature object for the specified algorithm.

Method Summary

Object	clone() Suppressed: Returns a clone if the implementation is cloneable.
private static void	debug(Exception e)
private static void	debug(String statement)
String	getAlgorithm() Enabled: Returns the name of the algorithm for this signature object.
static Signature	getInstance(String algorithm) Enabled: Generates a Signature object that implements the specified digest algorithm.
static Signature	getInstance(String algorithm, Provider provider) Enabled: Generates a Signature object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider.
static Signature	getInstance(String algorithm, String provider) Enabled: Generates a Signature object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider.
Object	getParameter(String param) Deprecated.
AlgorithmParameters	getParameters() Enabled: Returns the parameters used with this signature object.
Provider	getProvider() Enabled: Returns the provider of this signature object.
void	initSign(PrivateKey privateKey) Enabled: Initialize this object for signing.
void	initSign(PrivateKey privateKey, SecureRandom random) Enabled: Initialize this object for signing.
void	initVerify(java.security.cert.Certificate certificate) Enabled: Initializes this object for verification, using the public key from the given certificate.
void	initVerify(PublicKey publicKey) Enabled: Initializes this object for verification.
void	setParameter(AlgorithmParameterSpec params) Enabled: Initializes this signature engine with the specified parameter set.
void	setParameter(String param, Object value) Deprecated. Use setParameter.
byte[]	sign() Enabled: Returns the signature bytes of all the data updated.
int	sign(byte[] outbuf, int offset, int len) Enabled: Finishes the signature operation and stores the resulting signature bytes in the provided buffer outbuf, starting at offset.
String	toString() Suppressed: Returns a string representation of this signature object, providing information that includes the state of the object and the name of the algorithm used.
void	update(byte b) Enabled: Updates the data to be signed or verified by a byte.
void	update(byte[] data) Enabled: Updates the data to be signed or verified, using the specified array of bytes.
void	update(byte[] data, int off, int len) Enabled: Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.
boolean	verify(byte[] signature) Enabled: Verifies the passed-in signature.
boolean	verify(byte[] signature, int offset, int length) Enabled: Verifies the passed-in signature in the specified array of bytes, starting at the specified offset.

Methods inherited from class java.security.SignatureSpi

engineGetParameter, engineGetParameters, engineInitSign, engineInitSign, engineInitVerify, engineSetParameter, engineSetParameter, engineSign, engineSign, engineUpdate, engineUpdate, engineVerify, engineVerify

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

debug

private static final boolean debug

algorithm

private String algorithm

provider

private Provider provider

UNINITIALIZED

protected static final int UNINITIALIZED

Possible state value, signifying that this signature object has not yet been initialized.

SIGN

protected static final int SIGN

Possible state value, signifying that this signature object has been initialized for signing.

VERIFY

protected static final int VERIFY

Possible state value, signifying that this signature object has been initialized for verification.

state

protected int state

Current state of this signature object.

Constructor Detail

Signature

protected Signature(String algorithm)

Creates a Signature object for the specified algorithm.

Parameters:

algorithm - the standard string name of the algorithm. See Appendix A in the Java Cryptography Architecture API Specification & Reference for information about standard algorithm names.

Method Detail

getInstance

public static Signature getInstance(String algorithm)
                             throws NoSuchAlgorithmException

Enabled: Generates a Signature object that implements the specified digest algorithm. If the default provider package provides an implementation of the requested digest algorithm, an instance of Signature containing that implementation is returned. If the algorithm is not available in the default package, other packages are searched.

Parameters:

algorithm - the standard name of the algorithm requested. See Appendix A in the Java Cryptography Architecture API Specification & Reference for information about standard algorithm names.

Returns:

the new Signature object.

NoSuchAlgorithmException

getInstance

public static Signature getInstance(String algorithm,
                                    String provider)
                             throws NoSuchAlgorithmException,
                                    NoSuchProviderException

Enabled: Generates a Signature object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider.

Parameters:

algorithm - the name of the algorithm requested. See Appendix A in the Java Cryptography Architecture API Specification & Reference for information about standard algorithm names.

provider - the name of the provider.

Returns:

the new Signature object.

NoSuchAlgorithmException

NoSuchProviderException

See Also:

Provider

getInstance

public static Signature getInstance(String algorithm,
                                    Provider provider)
                             throws NoSuchAlgorithmException

Enabled: Generates a Signature object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider. Note: the provider doesn't have to be registered.

Parameters:

algorithm - the name of the algorithm requested. See Appendix A in the Java Cryptography Architecture API Specification & Reference for information about standard algorithm names.

provider - the provider.

Returns:

the new Signature object.

NoSuchAlgorithmException

Since:

1.4

See Also:

Provider

getProvider

public final Provider getProvider()

Enabled: Returns the provider of this signature object.

Returns:

the provider of this signature object

initVerify

public final void initVerify(PublicKey publicKey)
                      throws InvalidKeyException

Enabled: Initializes this object for verification. If this method is called again with a different argument, it negates the effect of this call.

Parameters:

publicKey - the public key of the identity whose signature is going to be verified.

InvalidKeyException

initVerify

public final void initVerify(java.security.cert.Certificate certificate)
                      throws InvalidKeyException

Enabled: Initializes this object for verification, using the public key from the given certificate.

If the certificate is of type X.509 and has a key usage extension field marked as critical, and the value of the key usage extension field implies that the public key in the certificate and its corresponding private key are not supposed to be used for digital signatures, an InvalidKeyException is thrown.

Parameters:

certificate - the certificate of the identity whose signature is going to be verified.

InvalidKeyException

initSign

public final void initSign(PrivateKey privateKey)
                    throws InvalidKeyException

Enabled: Initialize this object for signing. If this method is called again with a different argument, it negates the effect of this call.

Parameters:

privateKey - the private key of the identity whose signature is going to be generated.

InvalidKeyException

initSign

public final void initSign(PrivateKey privateKey,
                           SecureRandom random)
                    throws InvalidKeyException

Enabled: Initialize this object for signing. If this method is called again with a different argument, it negates the effect of this call.

Parameters:

privateKey - the private key of the identity whose signature is going to be generated.

random - the source of randomness for this signature.

InvalidKeyException

sign

public final byte[] sign()
                  throws SignatureException

Enabled: Returns the signature bytes of all the data updated. The format of the signature depends on the underlying signature scheme.

A call to this method resets this signature object to the state it was in when previously initialized for signing via a call to initSign(PrivateKey). That is, the object is reset and available to generate another signature from the same signer, if desired, via new calls to update and sign.

Returns:

the signature bytes of the signing operation's result.

SignatureException

sign

public final int sign(byte[] outbuf,
                      int offset,
                      int len)
               throws SignatureException

Enabled: Finishes the signature operation and stores the resulting signature bytes in the provided buffer outbuf, starting at offset. The format of the signature depends on the underlying signature scheme.

This signature object is reset to its initial state (the state it was in after a call to one of the initSign methods) and can be reused to generate further signatures with the same private key.

Parameters:

outbuf - buffer for the signature result.

offset - offset into outbuf where the signature is stored.

len - number of bytes within outbuf allotted for the signature.

Returns:

the number of bytes placed into outbuf.

SignatureException

Since:

1.2

verify

public final boolean verify(byte[] signature)
                     throws SignatureException

Enabled: Verifies the passed-in signature.

A call to this method resets this signature object to the state it was in when previously initialized for verification via a call to initVerify(PublicKey). That is, the object is reset and available to verify another signature from the identity whose public key was specified in the call to initVerify.

Parameters:

signature - the signature bytes to be verified.

Returns:

true if the signature was verified, false if not.

SignatureException

verify

public final boolean verify(byte[] signature,
                            int offset,
                            int length)
                     throws SignatureException

Enabled: Verifies the passed-in signature in the specified array of bytes, starting at the specified offset.

A call to this method resets this signature object to the state it was in when previously initialized for verification via a call to initVerify(PublicKey). That is, the object is reset and available to verify another signature from the identity whose public key was specified in the call to initVerify.

Parameters:

signature - the signature bytes to be verified.

offset - the offset to start from in the array of bytes.

length - the number of bytes to use, starting at offset.

Returns:

true if the signature was verified, false if not.

SignatureException

update

public final void update(byte b)
                  throws SignatureException

Enabled: Updates the data to be signed or verified by a byte.

Parameters:

b - the byte to use for the update.

SignatureException

update

public final void update(byte[] data)
                  throws SignatureException

Enabled: Updates the data to be signed or verified, using the specified array of bytes.

Parameters:

data - the byte array to use for the update.

SignatureException

update

public final void update(byte[] data,
                         int off,
                         int len)
                  throws SignatureException

Enabled: Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.

Parameters:

data - the array of bytes.

off - the offset to start from in the array of bytes.

len - the number of bytes to use, starting at offset.

SignatureException

getAlgorithm

public final String getAlgorithm()

Enabled: Returns the name of the algorithm for this signature object.

Returns:

the name of the algorithm for this signature object.

toString

public String toString()

Suppressed: Returns a string representation of this signature object, providing information that includes the state of the object and the name of the algorithm used.

Overrides:

toString in class Object

Returns:

a string representation of this signature object.

setParameter

public final void setParameter(String param,
                               Object value)
                        throws InvalidParameterException

Deprecated. Use setParameter.

Enabled: Sets the specified algorithm parameter to the specified value. This method supplies a general-purpose mechanism through which it is possible to set the various parameters of this object. A parameter may be any settable parameter for the algorithm, such as a parameter size, or a source of random bits for signature generation (if appropriate), or an indication of whether or not to perform a specific but optional computation. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.

Parameters:

param - the string identifier of the parameter.

value - the parameter value.

InvalidParameterException

See Also:

getParameter(java.lang.String)

setParameter

public final void setParameter(AlgorithmParameterSpec params)
                        throws InvalidAlgorithmParameterException

Enabled: Initializes this signature engine with the specified parameter set.

Parameters:

params - the parameters

InvalidAlgorithmParameterException

See Also:

getParameters()

getParameters

public final AlgorithmParameters getParameters()

Enabled: Returns the parameters used with this signature object.

The returned parameters may be the same that were used to initialize this signature, or may contain a combination of default and randomly generated parameter values used by the underlying signature implementation if this signature requires algorithm parameters but was not initialized with any.

Returns:

the parameters used with this signature, or null if this signature does not use any parameters.

See Also:

setParameter(AlgorithmParameterSpec)

getParameter

public final Object getParameter(String param)
                          throws InvalidParameterException

Deprecated.

Enabled: Gets the value of the specified algorithm parameter. This method supplies a general-purpose mechanism through which it is possible to get the various parameters of this object. A parameter may be any settable parameter for the algorithm, such as a parameter size, or a source of random bits for signature generation (if appropriate), or an indication of whether or not to perform a specific but optional computation. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.

Parameters:

param - the string name of the parameter.

Returns:

the object that represents the parameter value, or null if there is none.

InvalidParameterException

See Also:

setParameter(String, Object)

clone

public Object clone()
             throws CloneNotSupportedException

Suppressed: Returns a clone if the implementation is cloneable.

Overrides:

clone in class SignatureSpi

Returns:

a clone if the implementation is cloneable.

CloneNotSupportedException

debug

private static void debug(String statement)

debug

private static void debug(Exception e)