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Class java.security.SignatureSpi

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

public abstract class SignatureSpi
extends Object
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.

See Also:
Signature

Field Summary
SecureRandom  appRandom
Application-specified source of randomness.
 

Constructor Summary
 SignatureSpi()
 
 

Method Summary
Object  clone()
Returns a clone if the implementation is cloneable.
Object  engineGetParameter(String param)
Gets the value of the specified algorithm parameter. Deprecated
void  engineInitSign(PrivateKey privateKey)
Initializes this signature object with the specified private key for signing operations.
void  engineInitSign(PrivateKey privateKey, SecureRandom random)
Initializes this signature object with the specified private key and source of randomness for signing operations.
void  engineInitVerify(PublicKey publicKey)
Initializes this signature object with the specified public key for verification operations.
void  engineSetParameter(String param, Object value)
Sets the specified algorithm parameter to the specified value. Deprecated
void  engineSetParameter(AlgorithmParameterSpec params)
Initializes this signature engine with the specified parameter set.
byte[]  engineSign()
Returns the signature bytes of all the data updated so far.
void  engineUpdate(byte b)
Updates the data to be signed or verified using the specified byte.
void  engineUpdate(byte[] b, int off, int len)
Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.
boolean  engineVerify(byte[] sigBytes)
Verifies the passed-in signature.
 
Methods inherited from class java.lang.Object
 clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

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:
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.

engineSign

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.

engineVerify

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.

engineSetParameter

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.

engineSetParameter

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

engineGetParameter

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.

clone

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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