Signature

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java.security
Class Signature

java.lang.Object
  java.security.SignatureSpi
      java.security.Signature

Direct Known Subclasses:: DummySignature

public abstract class Signature
extends SignatureSpi

Signature is used to provide an interface to digital signature algorithms. Digital signatures provide authentication and data integrity of digital data.

The GNU provider provides the NIST standard DSA which uses DSA and SHA-1. It can be specified by SHA/DSA, SHA-1/DSA or its OID. If the RSA signature algorithm is provided then it could be MD2/RSA. MD5/RSA, or SHA-1/RSA. The algorithm must be specified because there is no default.

Signature provides implementation-independent algorithms which are requested by the user through the getInstance() methods. It can be requested by specifying just the algorithm name or by specifying both the algorithm name and provider name.


 
 The three phases of using Signature are:
 
 
   Initializing:
     
       It must be initialized with a private key for signing.
       It must be initialized with a public key for verifying.
   
   
   Updating:
   Update the bytes for signing or verifying with calls to update.
   
   
   Signing or Verify the signature on the currently stored bytes by
   calling sign or verify.
 















Field Summary



private  java.lang.String
algorithm



           



(package private)  Provider
provider



           



protected static int
SIGN



          Possible state value which signifies that this instance has been
 initialized for signing purposes.



private static java.lang.String
SIGNATURE



          Service name for signatures.



protected  int
state



          Current sate of this instance.



protected static int
UNINITIALIZED



          Possible state value which signifies that this instance has not yet been
 initialized.



protected static int
VERIFY



          Possible state value which signifies that this instance has been
 initialized for verification purposes.


 


Fields inherited from class java.security.SignatureSpi


appRandom


 






Constructor Summary



protected 
Signature(java.lang.String algorithm)



          Constructs a new Signature instance for a designated digital
 signature algorithm.


 






Method Summary



 java.lang.Object
clone()



          Returns a clone of this instance.



 java.lang.String
getAlgorithm()



          Returns the name of the algorithm currently used.



static Signature
getInstance(java.lang.String algorithm)



          Returns an instance of Signature representing the specified
 signature.



static Signature
getInstance(java.lang.String algorithm,
            Provider provider)



          Returns an instance of Signature representing the specified
 signature from the specified Provider.



static Signature
getInstance(java.lang.String algorithm,
            java.lang.String provider)



          Returns an instance of Signature representing the specified
 signature from the named provider.



 java.lang.Object
getParameter(java.lang.String param)



          Deprecated. use the other getParameter



 AlgorithmParameters
getParameters()



          Return the parameters of the algorithm used in this instance as an
 AlgorithmParameters.



 Provider
getProvider()



          Returns the Provider of this instance.



 void
initSign(PrivateKey privateKey)



          Initializes this class with the private key for signing purposes.



 void
initSign(PrivateKey privateKey,
         SecureRandom random)



          Initializes this class with the private key and source of randomness for
 signing purposes.



 void
initVerify(java.security.cert.Certificate certificate)



          Verify a signature with a designated Certificate.



 void
initVerify(PublicKey publicKey)



          Initializes this instance with the public key for verification purposes.



 void
setParameter(java.security.spec.AlgorithmParameterSpec params)



          Sets the signature engine with the specified java.security.spec.AlgorithmParameterSpec.



 void
setParameter(java.lang.String param,
             java.lang.Object value)



          Deprecated. use the other setParameter



 byte[]
sign()



          Returns the signature bytes of all the data fed to this instance.



 int
sign(byte[] outbuf,
     int offset,
     int len)



          Generates signature bytes of all the data fed to this instance and stores
 it in the designated array.



 java.lang.String
toString()



          Returns a rstring representation of this instance.



 void
update(byte b)



          Updates the data to be signed or verified with the specified byte.



 void
update(byte[] data)



          Updates the data to be signed or verified with the specified bytes.



 void
update(byte[] data,
       int off,
       int len)



          Updates the data to be signed or verified with the specified bytes.



 boolean
verify(byte[] signature)



          Verifies a designated signature.



 boolean
verify(byte[] signature,
       int offset,
       int length)



          Verifies a designated signature.


 


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




SIGNATURE
private static final java.lang.String SIGNATURE

Service name for signatures.


See Also:
Constant Field Values




UNINITIALIZED
protected static final int UNINITIALIZED

Possible state value which signifies that this instance has not yet been
 initialized.


See Also:
Constant Field Values




SIGN
protected static final int SIGN

Possible state value which signifies that this instance has been
 initialized for signing purposes.


See Also:
Constant Field Values




VERIFY
protected static final int VERIFY

Possible state value which signifies that this instance has been
 initialized for verification purposes.


See Also:
Constant Field Values




state
protected int state

Current sate of this instance.







algorithm
private java.lang.String algorithm







provider
Provider provider











Constructor Detail




Signature
protected Signature(java.lang.String algorithm)

Constructs a new Signature instance for a designated digital
 signature algorithm.









Method Detail




getInstance
public static Signature getInstance(java.lang.String algorithm)
                             throws NoSuchAlgorithmException

Returns an instance of Signature representing the specified
 signature.








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

Returns an instance of Signature representing the specified
 signature from the named provider.








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

Returns an instance of Signature representing the specified
 signature from the specified Provider.








getProvider
public final Provider getProvider()

Returns the Provider of this instance.








initVerify
public final void initVerify(PublicKey publicKey)
                      throws InvalidKeyException

Initializes this instance with the public key for verification purposes.








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

Verify a signature with a designated Certificate. This is a FIPS
 140-1 compatible method since it verifies a signature with a certificate.
 
 If the Certificate is an X.509 one, has a KeyUsage
 parameter and that parameter indicates this key is not to be used for
 signing then an exception is thrown.








initSign
public final void initSign(PrivateKey privateKey)
                    throws InvalidKeyException

Initializes this class with the private key for signing purposes.








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

Initializes this class with the private key and source of randomness for
 signing purposes.








sign
public final byte[] sign()
                  throws SignatureException

Returns the signature bytes of all the data fed to this instance. The
 format of the output depends on the underlying signature algorithm.








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

Generates signature bytes of all the data fed to this instance and stores
 it in the designated array. The format of the result depends on the
 underlying signature algorithm.
 
 After calling this method, the instance is reset to its initial state
 and can then be used to generate additional signatures.
 
 IMPLEMENTATION NOTE: Neither this method nor the GNU provider
 will return partial digests. If len is less than the
 signature length, this method will throw a SignatureException. If
 it is greater than or equal then it is ignored.


Since:
  1.2






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

Verifies a designated signature.








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

Verifies a designated signature.








update
public final void update(byte b)
                  throws SignatureException

Updates the data to be signed or verified with the specified byte.








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

Updates the data to be signed or verified with the specified bytes.








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

Updates the data to be signed or verified with the specified bytes.








getAlgorithm
public final java.lang.String getAlgorithm()

Returns the name of the algorithm currently used. The names of algorithms
 are usually SHA/DSA or SHA/RSA.








toString
public java.lang.String toString()

Returns a rstring representation of this instance.








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

Deprecated. use the other setParameter

Sets the specified algorithm parameter to the specified value.








setParameter
public final void setParameter(java.security.spec.AlgorithmParameterSpec params)
                        throws InvalidAlgorithmParameterException

Sets the signature engine with the specified java.security.spec.AlgorithmParameterSpec.
 
 By default, and unless overriden by the concrete SPI, this method always
 throws an java.lang.UnsupportedOperationException.








getParameters
public final AlgorithmParameters getParameters()

Return the parameters of the algorithm used in this instance as an
 AlgorithmParameters.








getParameter
public final java.lang.Object getParameter(java.lang.String param)
                                    throws InvalidParameterException

Deprecated. use the other getParameter

Returns the value for the specified algorithm parameter.








clone
public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Returns a clone of this instance.


Overrides:
clone in class SignatureSpi














  
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Field Summary
`private java.lang.String`	`algorithm`
`(package private) Provider`	`provider`
`protected static int`	`SIGN` Possible state value which signifies that this instance has been initialized for signing purposes.
`private static java.lang.String`	`SIGNATURE` Service name for signatures.
`protected int`	`state` Current sate of this instance.
`protected static int`	`UNINITIALIZED` Possible state value which signifies that this instance has not yet been initialized.
`protected static int`	`VERIFY` Possible state value which signifies that this instance has been initialized for verification purposes.

Method Summary
`java.lang.Object`	`clone()` Returns a clone of this instance.
`java.lang.String`	`getAlgorithm()` Returns the name of the algorithm currently used.
`static Signature`	`getInstance(java.lang.String algorithm)` Returns an instance of `Signature` representing the specified signature.
`static Signature`	`getInstance(java.lang.String algorithm, Provider provider)` Returns an instance of `Signature` representing the specified signature from the specified Provider.
`static Signature`	`getInstance(java.lang.String algorithm, java.lang.String provider)` Returns an instance of `Signature` representing the specified signature from the named provider.
`java.lang.Object`	`getParameter(java.lang.String param)` Deprecated. use the other getParameter
`AlgorithmParameters`	`getParameters()` Return the parameters of the algorithm used in this instance as an AlgorithmParameters.
`Provider`	`getProvider()` Returns the Provider of this instance.
`void`	`initSign(PrivateKey privateKey)` Initializes this class with the private key for signing purposes.
`void`	`initSign(PrivateKey privateKey, SecureRandom random)` Initializes this class with the private key and source of randomness for signing purposes.
`void`	`initVerify(java.security.cert.Certificate certificate)` Verify a signature with a designated Certificate.
`void`	`initVerify(PublicKey publicKey)` Initializes this instance with the public key for verification purposes.
`void`	`setParameter(java.security.spec.AlgorithmParameterSpec params)` Sets the signature engine with the specified java.security.spec.AlgorithmParameterSpec.
`void`	`setParameter(java.lang.String param, java.lang.Object value)` Deprecated. use the other setParameter
`byte[]`	`sign()` Returns the signature bytes of all the data fed to this instance.
`int`	`sign(byte[] outbuf, int offset, int len)` Generates signature bytes of all the data fed to this instance and stores it in the designated array.
`java.lang.String`	`toString()` Returns a rstring representation of this instance.
`void`	`update(byte b)` Updates the data to be signed or verified with the specified byte.
`void`	`update(byte[] data)` Updates the data to be signed or verified with the specified bytes.
`void`	`update(byte[] data, int off, int len)` Updates the data to be signed or verified with the specified bytes.
`boolean`	`verify(byte[] signature)` Verifies a designated signature.
`boolean`	`verify(byte[] signature, int offset, int length)` Verifies a designated signature.

Constructor Summary
`protected`	`Signature(java.lang.String algorithm)` Constructs a new `Signature` instance for a designated digital signature algorithm.

java.security Class Signature

SIGNATURE

UNINITIALIZED

SIGN

VERIFY

state

algorithm

provider

Signature

getInstance

getInstance

getInstance

getProvider

initVerify

initVerify

initSign

initSign

sign

sign

verify

verify

update

update

update

getAlgorithm

toString

setParameter

setParameter

getParameters

getParameter

clone

java.security
Class Signature