Class SignatureSpi

Field Detail

• appRandom

  protected SecureRandom appRandom

  Application-specified source of randomness.

Constructor Detail

• SignatureSpi

  public SignatureSpi()

Method Detail

• engineInitVerify

  protected abstract void engineInitVerify(PublicKey publicKey)
                                    throws InvalidKeyException

  Initializes this signature object with the specified public key for verification operations.

  Parameters:

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

  Throws:

  InvalidKeyException - if the key is improperly encoded, parameters are missing, and so on.

• engineInitSign

  protected abstract void engineInitSign(PrivateKey privateKey)
                                  throws InvalidKeyException

  Initializes this signature object with the specified private key for signing operations.

  Parameters:

  privateKey - the private key of the identity whose signature will be generated.

  Throws:

  InvalidKeyException - if the key is improperly encoded, parameters are missing, and so on.

• engineInitSign

  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.)

  Parameters:

  privateKey - the private key of the identity whose signature will be generated.

  random - the source of randomness

  Throws:

  InvalidKeyException - if the key is improperly encoded, parameters are missing, and so on.

• engineUpdate

  protected abstract void engineUpdate(byte b)
                                throws SignatureException

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

  Parameters:

  b - the byte to use for the update.

  Throws:

  SignatureException - if the engine is not initialized properly.

• engineUpdate

  protected abstract 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.

  Parameters:

  b - 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

  Throws:

  SignatureException - if the engine is not initialized properly

• engineUpdate

  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.

  Parameters:

  input - the ByteBuffer

  Since:

  1.5

• engineSign

  protected abstract 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.

  Returns:

  the signature bytes of the signing operation's result.

  Throws:

  SignatureException - if the engine is not initialized properly or if this signature algorithm is unable to process the input data provided.

• engineSign

  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.

  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. Both this default implementation and the SUN provider do not return partial digests. If the value of this parameter is less than the actual signature length, this method will throw a SignatureException. This parameter is ignored if its value is greater than or equal to the actual signature length.

  Returns:

  the number of bytes placed into outbuf

  Throws:

  SignatureException - if the engine is not initialized properly, if this signature algorithm is unable to process the input data provided, or if len is less than the actual signature length.

  Since:

  1.2

• engineVerify

  protected abstract boolean engineVerify(byte[] sigBytes)
                                   throws SignatureException

  Verifies the passed-in signature.

  Parameters:

  sigBytes - the signature bytes to be verified.

  Returns:

  true if the signature was verified, false if not.

  Throws:

  SignatureException - if the engine is not initialized properly, the passed-in signature is improperly encoded or of the wrong type, if this signature algorithm is unable to process the input data provided, etc.

• engineVerify

  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.

  Parameters:

  sigBytes - 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.

  Throws:

  SignatureException - if the engine is not initialized properly, the passed-in signature is improperly encoded or of the wrong type, if this signature algorithm is unable to process the input data provided, etc.

  Since:

  1.4

• engineSetParameter

  @Deprecated
  protected abstract void engineSetParameter(String param,
                                   Object value)
                                      throws InvalidParameterException

  Deprecated. 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.

  Parameters:

  param - the string identifier of the parameter.

  value - the parameter value.

  Throws:

  InvalidParameterException - if param is an invalid parameter for this signature algorithm engine, the parameter is already set and cannot be set again, a security exception occurs, and so on.

• engineSetParameter

  protected void engineSetParameter(AlgorithmParameterSpec params)
                             throws InvalidAlgorithmParameterException

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

  Parameters:

  params - the parameters

  Throws:

  UnsupportedOperationException - if this method is not overridden by a provider

  InvalidAlgorithmParameterException - if this method is overridden by a provider and the given parameters are inappropriate for this signature engine

• engineGetParameters

  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.

  Returns:

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

  Throws:

  UnsupportedOperationException - if this method is not overridden by a provider

  Since:

  1.4

• engineGetParameter

  @Deprecated
  protected abstract Object engineGetParameter(String param)
                                        throws InvalidParameterException

  Deprecated. 
  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.

  Throws:

  InvalidParameterException - if param is an invalid parameter for this engine, or another exception occurs while trying to get this parameter.

• clone

  public Object clone()
               throws CloneNotSupportedException

  Returns a clone if the implementation is cloneable.

  Overrides:

  clone in class Object

  Returns:

  a clone if the implementation is cloneable.

  Throws:

  CloneNotSupportedException - if this is called on an implementation that does not support Cloneable.

  See Also:

  Cloneable