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java.security
abstract public class: SignatureSpi [javadoc | source]
java.lang.Object
   java.security.SignatureSpi

Direct Known Subclasses:
    DummySignature, Signature, Delegate, CipherAdapter

This class defines the Service Provider Interface (SPI) for the Signature class, which is used to provide the functionality of a digital signature algorithm. Digital signatures are used for authentication and integrity assurance of digital data. .

All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply the implementation of a particular signature algorithm.

Field Summary
protected  SecureRandom appRandom    Application-specified source of randomness. 
Method from java.security.SignatureSpi Summary:
clone,   engineGetParameter,   engineGetParameters,   engineInitSign,   engineInitSign,   engineInitVerify,   engineSetParameter,   engineSetParameter,   engineSign,   engineSign,   engineUpdate,   engineUpdate,   engineUpdate,   engineVerify,   engineVerify
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.security.SignatureSpi Detail:
 public Object clone() throws CloneNotSupportedException 
    Returns a clone if the implementation is cloneable.
 abstract protected Object engineGetParameter(String param) throws InvalidParameterExceptionDeprecated! 
    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.
 protected AlgorithmParameters engineGetParameters() 

    This method is overridden by providers to return the parameters used with this signature engine, or null if this signature engine does not use any parameters.

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

 abstract protected  void engineInitSign(PrivateKey privateKey) throws InvalidKeyException
    Initializes this signature object with the specified private key for signing operations.
 protected  void engineInitSign(PrivateKey privateKey,
    SecureRandom random) throws InvalidKeyException 
    Initializes this signature object with the specified private key and source of randomness for signing operations.

    This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.)

 abstract protected  void engineInitVerify(PublicKey publicKey) throws InvalidKeyException
    Initializes this signature object with the specified public key for verification operations.
 protected  void engineSetParameter(AlgorithmParameterSpec params) throws InvalidAlgorithmParameterException 

    This method is overridden by providers to initialize this signature engine with the specified parameter set.

 abstract protected  void engineSetParameter(String param,
    Object value) throws InvalidParameterExceptionDeprecated! Replaced -  by engineSetParameter .

    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.
 abstract protected byte[] engineSign() throws SignatureException
    Returns the signature bytes of all the data updated so far. The format of the signature depends on the underlying signature scheme.
 protected int engineSign(byte[] outbuf,
    int offset,
    int len) throws SignatureException 
    Finishes this 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.

    The signature implementation is reset to its initial state (the state it was in after a call to one of the engineInitSign methods) and can be reused to generate further signatures with the same private key. This method should be abstract, but we leave it concrete for binary compatibility. Knowledgeable providers should override this method.

 abstract protected  void engineUpdate(byte b) throws SignatureException
    Updates the data to be signed or verified using the specified byte.
 protected  void engineUpdate(ByteBuffer input) 
    Updates the data to be signed or verified using the specified ByteBuffer. Processes the data.remaining() bytes starting at at data.position(). Upon return, the buffer's position will be equal to its limit; its limit will not have changed.
 abstract protected  void engineUpdate(byte[] b,
    int off,
    int len) throws SignatureException
    Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.
 abstract protected boolean engineVerify(byte[] sigBytes) throws SignatureException
    Verifies the passed-in signature.
 protected boolean engineVerify(byte[] sigBytes,
    int offset,
    int length) throws SignatureException 
    Verifies the passed-in signature in the specified array of bytes, starting at the specified offset.

    Note: Subclasses should overwrite the default implementation.