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SUMMARY: JavaDoc of javax.crypto.CipherSpi JAVADOC | Sourc code of javax.crypto.CipherSpi SOURCE | Download javax.crypto.CipherSpi DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD

javax.crypto
Class CipherSpi  view CipherSpi download CipherSpi.java

java.lang.Object
  extended byjavax.crypto.CipherSpi
Direct Known Subclasses:
NullCipherImpl, NullCipherSpi
public abstract class CipherSpi
extends java.lang.Object

This class represents the Service Provider Interface (SPI) for cryptographic ciphers.

Providers of cryptographic ciphers must subclass this for every cipher they implement, implementing the abstract methods as appropriate, then provide an entry that points to the subclass in their implementation of java.security.Provider.

CipherSpi objects are instantiated along with Ciphers when the Cipher.getInstance(java.lang.String) 55 methods are invoked. Particular ciphers are referenced by a transformation, which is a String consisting of the cipher's name or the ciper's name followed by a mode and a padding. Transformations all follow the general form:

Cipher names in the master java.security.Provider class may be:

  1. The algorithm's name, which uses a pluggable mode and padding: Cipher.algorithm
  2. The algorithm's name and the mode, which uses pluggable padding: Cipher.algorithm/mode
  3. The algorithm's name and the padding, which uses a pluggable mode: Cipher.algorithm//padding
  4. The algorihtm's name, the mode, and the padding: Cipher.algorithm/mode/padding

When any Cipher.getInstance(java.lang.String) 55 method is invoked, the following happens if the transformation is simply algorithm:

  1. If the provider defines a CipherSpi implementation for "algorithm", return it. Otherwise throw a java.security.NoSuchAlgorithmException.

If the transformation is of the form algorithm/mode/padding:

  1. If the provider defines a CipherSpi subclass for "algorithm/mode/padding", return it. Otherwise go to step 2.
  2. If the provider defines a CipherSpi subclass for "algorithm/mode", instatiate it, call engineSetPadding(java.lang.String) 55 for the padding name, and return it. Otherwise go to step 3.
  3. If the provider defines a CipherSpi subclass for "algorithm//padding", instatiate it, call engineSetMode(java.lang.String) 55 for the mode name, and return it. Otherwise go to step 4.
  4. If the provider defines a CipherSpi subclass for "algorithm", instatiate it, call engineSetMode(java.lang.String) 55 for the mode name, call engineSetPadding(java.lang.String) 55 for the padding name, and return it. Otherwise throw a java.security.NoSuchAlgorithmException.

Since:
1.4

Constructor Summary
CipherSpi()
          Create a new CipherSpi.
 
Method Summary
protected abstract  byte[] engineDoFinal(byte[] input, int inputOffset, int inputLength)
          Finishes a multi-part transformation or transforms a portion of a byte array, and returns the transformed bytes.
protected abstract  int engineDoFinal(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset)
          Finishes a multi-part transformation or transforms a portion of a byte array, and stores the transformed bytes in the supplied array.
protected  int engineDoFinal(java.nio.ByteBuffer input, java.nio.ByteBuffer output)
           
protected abstract  int engineGetBlockSize()
          Returns the block size of the underlying cipher.
protected abstract  byte[] engineGetIV()
          Returns the initializaiton vector this cipher was initialized with, if any.
protected  int engineGetKeySize(java.security.Key key)
          Return the length of the given key in bits.
protected abstract  int engineGetOutputSize(int inputLength)
          Returns the size, in bytes, an output buffer must be for a call to engineUpdate(byte[],int,int,byte[],int) 55 or engineDoFinal(byte[],int,int,byte[],int) 55 to succeed.
protected abstract  java.security.AlgorithmParameters engineGetParameters()
          Returns the parameters that this cipher is using.
protected abstract  void engineInit(int opmode, java.security.Key key, java.security.spec.AlgorithmParameterSpec params, java.security.SecureRandom random)
          Initializes this cipher with an operation mode, key, parameters, and source of randomness.
protected abstract  void engineInit(int opmode, java.security.Key key, java.security.AlgorithmParameters params, java.security.SecureRandom random)
          Initializes this cipher with an operation mode, key, parameters, and source of randomness.
protected abstract  void engineInit(int opmode, java.security.Key key, java.security.SecureRandom random)
          Initializes this cipher with an operation mode, key, and source of randomness.
protected abstract  void engineSetMode(java.lang.String mode)
          Set the mode in which this cipher is to run.
protected abstract  void engineSetPadding(java.lang.String padding)
          Set the method with which the input is to be padded.
protected  java.security.Key engineUnwrap(byte[] wrappedKey, java.lang.String wrappedKeyAlgorithm, int wrappedKeyType)
          Unwraps a previously-wrapped key.
protected abstract  byte[] engineUpdate(byte[] input, int inputOffset, int inputLength)
          Continue with a multi-part transformation, returning a new array of the transformed bytes.
protected abstract  int engineUpdate(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset)
          Continue with a multi-part transformation, storing the transformed bytes into the specified array.
protected  int engineUpdate(java.nio.ByteBuffer input, java.nio.ByteBuffer output)
           
protected  byte[] engineWrap(java.security.Key key)
          Wrap a key.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

CipherSpi

public CipherSpi()
Create a new CipherSpi.

Method Detail

engineDoFinal

protected abstract byte[] engineDoFinal(byte[] input,
                                        int inputOffset,
                                        int inputLength)
                                 throws IllegalBlockSizeException,
                                        BadPaddingException
Finishes a multi-part transformation or transforms a portion of a byte array, and returns the transformed bytes.

engineDoFinal

protected abstract int engineDoFinal(byte[] input,
                                     int inputOffset,
                                     int inputLength,
                                     byte[] output,
                                     int outputOffset)
                              throws IllegalBlockSizeException,
                                     BadPaddingException,
                                     ShortBufferException
Finishes a multi-part transformation or transforms a portion of a byte array, and stores the transformed bytes in the supplied array.

engineDoFinal

protected int engineDoFinal(java.nio.ByteBuffer input,
                            java.nio.ByteBuffer output)
                     throws BadPaddingException,
                            IllegalBlockSizeException,
                            ShortBufferException
Since:
1.5

engineGetBlockSize

protected abstract int engineGetBlockSize()
Returns the block size of the underlying cipher.

engineGetIV

protected abstract byte[] engineGetIV()
Returns the initializaiton vector this cipher was initialized with, if any.

engineGetKeySize

protected int engineGetKeySize(java.security.Key key)
                        throws java.security.InvalidKeyException

Return the length of the given key in bits.

For compatibility this method is not declared abstract, and the default implementation will throw an java.lang.UnsupportedOperationException. Concrete subclasses should override this method to return the correct value.

engineGetOutputSize

protected abstract int engineGetOutputSize(int inputLength)

Returns the size, in bytes, an output buffer must be for a call to engineUpdate(byte[],int,int,byte[],int) 55 or engineDoFinal(byte[],int,int,byte[],int) 55 to succeed.

The actual output length may be smaller than the value returned by this method, as it considers the padding length as well. The length considered is the argument plus the length of any buffered, unprocessed bytes.

engineGetParameters

protected abstract java.security.AlgorithmParameters engineGetParameters()
Returns the parameters that this cipher is using. This may be the parameters used to initialize this cipher, or it may be parameters that have been initialized with random values.

engineInit

protected abstract void engineInit(int opmode,
                                   java.security.Key key,
                                   java.security.SecureRandom random)
                            throws java.security.InvalidKeyException
Initializes this cipher with an operation mode, key, and source of randomness. If this cipher requires any other initializing data, for example an initialization vector, then it should generate it from the provided source of randomness.

engineInit

protected abstract void engineInit(int opmode,
                                   java.security.Key key,
                                   java.security.AlgorithmParameters params,
                                   java.security.SecureRandom random)
                            throws java.security.InvalidAlgorithmParameterException,
                                   java.security.InvalidKeyException
Initializes this cipher with an operation mode, key, parameters, and source of randomness. If this cipher requires any other initializing data, for example an initialization vector, then it should generate it from the provided source of randomness.

engineInit

protected abstract void engineInit(int opmode,
                                   java.security.Key key,
                                   java.security.spec.AlgorithmParameterSpec params,
                                   java.security.SecureRandom random)
                            throws java.security.InvalidAlgorithmParameterException,
                                   java.security.InvalidKeyException
Initializes this cipher with an operation mode, key, parameters, and source of randomness. If this cipher requires any other initializing data, for example an initialization vector, then it should generate it from the provided source of randomness.

engineSetMode

protected abstract void engineSetMode(java.lang.String mode)
                               throws java.security.NoSuchAlgorithmException
Set the mode in which this cipher is to run.

engineSetPadding

protected abstract void engineSetPadding(java.lang.String padding)
                                  throws NoSuchPaddingException
Set the method with which the input is to be padded.

engineUnwrap

protected java.security.Key engineUnwrap(byte[] wrappedKey,
                                         java.lang.String wrappedKeyAlgorithm,
                                         int wrappedKeyType)
                                  throws java.security.InvalidKeyException,
                                         java.security.NoSuchAlgorithmException

Unwraps a previously-wrapped key.

For compatibility this method is not declared abstract, and the default implementation will throw an java.lang.UnsupportedOperationException.

engineUpdate

protected abstract byte[] engineUpdate(byte[] input,
                                       int inputOffset,
                                       int inputLength)
Continue with a multi-part transformation, returning a new array of the transformed bytes.

engineUpdate

protected abstract int engineUpdate(byte[] input,
                                    int inputOffset,
                                    int inputLength,
                                    byte[] output,
                                    int outputOffset)
                             throws ShortBufferException
Continue with a multi-part transformation, storing the transformed bytes into the specified array.

engineUpdate

protected int engineUpdate(java.nio.ByteBuffer input,
                           java.nio.ByteBuffer output)
                    throws ShortBufferException
Since:
1.5

engineWrap

protected byte[] engineWrap(java.security.Key key)
                     throws java.security.InvalidKeyException,
                            IllegalBlockSizeException

Wrap a key.

For compatibility this method is not declared abstract, and the default implementation will throw an java.lang.UnsupportedOperationException.

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SUMMARY: JavaDoc of javax.crypto.CipherSpi JAVADOC | Sourc code of javax.crypto.CipherSpi SOURCE | Download javax.crypto.CipherSpi DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD