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Class java.security.SignatureSpi

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

public abstract class SignatureSpi

extends Object

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

See Also:

Signature

appRandom

SignatureSpi()

clone()

Returns a clone if the implementation is cloneable.

engineGetParameter(String)

Gets the value of the specified algorithm parameter. Deprecated.

engineInitSign(PrivateKey)

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

engineInitSign(PrivateKey, SecureRandom)

Initializes this signature object with the specified private key and source of randomness for signing operations.

engineInitVerify(PublicKey)

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

engineSetParameter(AlgorithmParameterSpec)

Initializes this signature engine with the specified parameter set.

engineSetParameter(String, Object)

Sets the specified algorithm parameter to the specified value. Deprecated.

engineSign()

Returns the signature bytes of all the data updated so far.

engineUpdate(byte)

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

engineUpdate(byte[], int, int)

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

engineVerify(byte[])

Verifies the passed-in signature.

protected SecureRandom appRandom

public SignatureSpi()

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.

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.

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.

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.

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:

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.

Throws: SignatureException

if the engine is not initialized properly.

protected abstract byte[] engineSign() throws SignatureException

Returns the signature bytes of all the data updated so far. The signature returned is X.509-encoded. For more information about the X.509 encoding, see X.509 certificates.

Returns:

the signature bytes of the signing operation's result.

Throws: SignatureException

if the engine is not initialized properly.

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

Verifies the passed-in signature. The signature bytes are expected to be X.509-encoded. For more information about the X.509 encoding, see X.509 certificates.

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, or the passed-in signature is improperly encoded or of the wrong type, etc.

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

Note: engineSetParameter() is 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.

protected void engineSetParameter(AlgorithmParameterSpec params) throws InvalidAlgorithmParameterException

Initializes this signature engine with the specified parameter set. This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.) It may be overridden by a provider to set the algorithm parameters using the specified params. Such an override is expected to throw an InvalidAlgorithmParameterException if a parameter is invalid. If this method is not overridden, it always throws an UnsupportedOperationException.

Parameters:

params - the parameters

Throws: InvalidAlgorithmParameterException

if the given parameters are inappropriate for this signature engine

protected abstract Object engineGetParameter(String param) throws InvalidParameterException

Note: engineGetParameter() is 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.

public Object clone() throws CloneNotSupportedException

Returns a clone if the implementation is cloneable.

Returns:

a clone if the implementation is cloneable.

Throws: CloneNotSupportedException

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

Overrides:

clone in class Object

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