com.motorola.iden.provider
Class RSA

java.lang.Object
  |
  +--com.motorola.iden.crypto.CipherSpi
        |
        +--com.motorola.iden.provider.RSA

public final class RSA

extends CipherSpi

The RSA encryption algorithm, with PKCS1v15Padding.

If the number of bits in the modulus is bitlength,the bitlength should be greater than 384 and less than 1024. Otherwise, an InvalidKeyException will be thrown.

For public key operation, key must be an instance of com.motorola.iden.crypto.RSA_PublicKey.

For private key operation, key must be an instance of com.motorola.iden.crypto.RSA_PrivateKey.

When in DECRYPT mode,ciphertext block sizes should be (int) (bitlength/8). Otherwise, IllegalBlockSizeException will be thrown.

When in ENCRYPT mode, the plaintext block size sould be less than (int)(bitlength/8)-11. Otherwise, IllegalBlockSizeException will be thrown.

MOTOROLA and the Stylized M Logo are registered trademarks of Motorola, Inc. Reg. U.S. Pat. & Tm. Off.
© Copyright 2002 - 2004 Motorola, Inc. All Rights Reserved.

See Also:

[CipherSpi]

Constructor Summary

RSA()

Method Summary

protected byte[]	engineDoFinal(byte[] input, int inputOffset, int inputLen) Encrypts or decrypts data in a single-part operation, The data is encrypted or decrypted, depending on how this cipher was initialized.
protected int	engineGetBlockSize() Returns the block size (in bytes).
protected byte[]	engineGetIV() RSA does not use IV
protected void	engineInit(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random) Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.
protected void	engineSetMode(java.lang.String mode) Sets the mode of this cipher.
protected void	engineSetPadding(java.lang.String padding) Sets the padding mechanism of this cipher.
protected byte[]	engineUpdate(byte[] input, int inputOffset, int inputLen) NOT implemented in RSA cipher.
protected void	finalize()

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RSA

public RSA()

Method Detail

engineSetMode

protected void engineSetMode(java.lang.String mode)
                      throws NoSuchAlgorithmException

Sets the mode of this cipher.(ECB only for RSA Cipher)

Overrides:

engineSetMode in class CipherSpi

Parameters:

mode - the cipher mode

Throws:

NoSuchAlgorithmException - if the requested cipher mode does not exist

engineSetPadding

protected void engineSetPadding(java.lang.String padding)
                         throws NoSuchPaddingException

Sets the padding mechanism of this cipher.(PKCS#1v15 only for RSA Cipher)

Overrides:

engineSetPadding in class CipherSpi

Parameters:

padding - the padding mechanism

Throws:

NoSuchPaddingException - if the requested padding mechanism does not exist

engineGetBlockSize

protected int engineGetBlockSize()

Returns the block size (in bytes).

Overrides:

engineGetBlockSize in class CipherSpi

Returns:

the block size (in bytes), or 0 if the underlying algorithm is not a block cipher

engineGetIV

protected byte[] engineGetIV()

RSA does not use IV

Overrides:

engineGetIV in class CipherSpi

Throws:

java.lang.SecurityException - if called.

engineInit

protected void engineInit(int opmode,
                          Key key,
                          AlgorithmParameterSpec params,
                          SecureRandom random)
                   throws InvalidKeyException,
                          InvalidAlgorithmParameterException

Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption,depending on the value of opmode.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

Overrides:

engineInit in class CipherSpi

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE

key - the encryption key, must be instance of com.mot.provider.RSAPublicKey or com.mot.provider.RSAPrivateKey.

params - the algorithm parameters, always set to null in RSA cipher.

random - the source of randomness, always set to null in RSA cipher.

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher

InvalidAlgorithmParameterException - if opmode is not Cipher.ECRYPT or Cipher.DECRYPT.

engineUpdate

protected byte[] engineUpdate(byte[] input,
                              int inputOffset,
                              int inputLen)

NOT implemented in RSA cipher.

Overrides:

engineUpdate in class CipherSpi

Throws:

java.lang.SecurityException - if called.

engineDoFinal

protected byte[] engineDoFinal(byte[] input,
                               int inputOffset,
                               int inputLen)
                        throws IllegalBlockSizeException,
                               BadPaddingException

Encrypts or decrypts data in a single-part operation, The data is encrypted or decrypted, depending on how this cipher was initialized.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, with padding (if requested) being applied. The result is stored in a new buffer.

A call to this method resets this cipher object to the state it was in when previously initialized via a call to engineInit. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to engineInit) more data.

Overrides:

engineDoFinal in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

the new buffer with the result

Throws:

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

finalize

protected void finalize()

Overrides:

finalize in class java.lang.Object