iaik.security.rsa

Class RSA

java.lang.Object

javax.crypto.CipherSpi

iaik.pkcs.pkcs1.RSACipher

iaik.security.rsa.RSA

public class RSA
extends RSACipher

This class implements the RSA Cipher algorithm. This class only extends iaik.pkcs.pkcs.RSACipher into this package to make accessible the protected methods for the RSA signature engine. To avoid problems due to JCE provider verification and cipher key length checks, the RSA signature engine does not use the JCE Cipher engine API anymore.

Version:

File Revision 11

See Also:

RSACipher

Field Summary

Fields

Modifier and Type	Field and Description
static int	DECRYPT_MODE Cipher decryption mode.
static int	ENCRYPT_MODE Cipher encryption mode.

Fields inherited from class iaik.pkcs.pkcs1.RSACipher

privKey, pubKey

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RSA() Default Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected byte[]	doFinal(byte[] in, int inOff, int inLen) Performs a modulo exponentiation.
java.security.SecureRandom	getSecureRandom() Gets the SecureRandom used by this Signature engine.
protected void	init(int opmode, java.security.Key key, java.security.SecureRandom random) Initializes this RSA cipher with the given key.
protected void	setMode(java.lang.String mode) Sets the block mode of the encryption block according to PKCS#1.
protected void	setPadding(java.lang.String padding) Sets the padding scheme of this cipher.
static void	setRSACipherFactory(RSACipherFactory factory) Sets the RSA Cipher factory.
void	setSecureRandom(java.security.SecureRandom random) Sets the SecureRandom to be used by this Signature engine.

Methods inherited from class iaik.pkcs.pkcs1.RSACipher

engineDoFinal, engineDoFinal, engineGetBlockSize, engineGetIV, engineGetKeySize, engineGetOutputSize, engineGetParameters, engineInit, engineInit, engineInit, engineSetMode, engineSetPadding, engineUnwrap, engineUpdate, engineUpdate, engineWrap, isUseBlinding, isUseBlindingDefault, rawCrypt, rawPrivateRSA, rawPublicRSA, setDoVerifyCRTSignature, setUseBlinding, setUseBlindingDefault, setValidateAgainstOaepKeyParameters

Methods inherited from class javax.crypto.CipherSpi

engineDoFinal, engineUpdate, engineUpdateAAD, engineUpdateAAD

Methods inherited from class java.lang.Object

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

Field Detail

ENCRYPT_MODE

public static final int ENCRYPT_MODE

Cipher encryption mode.

See Also:

Constant Field Values

DECRYPT_MODE

public static final int DECRYPT_MODE

Cipher decryption mode.

See Also:

Constant Field Values

Constructor Detail

RSA

protected RSA()

Default Constructor.

Method Detail

setRSACipherFactory

public static void setRSACipherFactory(RSACipherFactory factory)

Sets the RSA Cipher factory. Any Signature engine of this package uses the RSACipherFactory set by this method to get a RSA cipher object when required for RSA based en/decryption operations.
An application may use this method to plug in its own RSA Cipher implementation, e.g.:

 // custom RSA cipher implementation
 class MyRSACipherImpl extends RSA {
   ...
 }

 public class MyRSACipherFactory implements RSACipherFactory {

   public RSACipherFactory() {
   }

   public RSA getInstance() {
     return new MyRSACipherImpl();
   }
 }

 // Now tell the RSA Signature library to use the custom RSACiperFactory:
 RSA.setRSACipherFactory(new MyRSACipherFactory());
 

Parameters:

factory - the RSACipherFactory to be used

init

protected void init(int opmode,
        java.security.Key key,
        java.security.SecureRandom random)
             throws java.security.InvalidKeyException

Initializes this RSA cipher with the given key.

Before a cipher object is ready for data processing, it has to be initialized according to the desired cryptographic operation, which is specified by the opmode parameter (either ENCRYPT_MODE or DECRYPT_MODE).

The key either will be a RSAPrivateKey or a RSAPublicKey, depending on the specific cryptographic operation to be performed. This class supports keys represented by IAIK specific classes as well as java.security.spec.RSA*KeySpec, java.security.interfaces.RSA*Key, as well as java.security.PublicKey and java.security.PrivateKey that ASN.1 code themselves as RSA keys.

Parameters:

opmode - ENCRYPT_MODE or DECRYPT_MODE

key - an instance of a RSA PublicKey or RSA PrivateKey

random - source of randomness

Throws:

java.security.InvalidKeyException - if the RSA key cannot be created

setPadding

protected void setPadding(java.lang.String padding)
                   throws java.lang.Exception

Sets the padding scheme of this cipher.

Parameters:

padding - the padding scheme for this RSA cipher

Throws:

java.lang.Exception - if the requested padding is not supported

setMode

protected void setMode(java.lang.String mode)
                throws java.security.NoSuchAlgorithmException

Sets the block mode of the encryption block according to PKCS#1. The block mode shall be 0 or 1 for a private key operation, and 2 for a public key operation. If "ECB" is specified as mode, the block type is automatically selected.

Parameters:

mode - the block type (0,1 or 2)

Throws:

java.security.NoSuchAlgorithmException - if the block type is not 0,1 or 2

doFinal

protected byte[] doFinal(byte[] in,
             int inOff,
             int inLen)
                  throws java.lang.Exception

Performs a modulo exponentiation.

The data to be processed is given in an input byte array. Beginning at inputOffset, only the first inputLen bytes are en/decrypted. The result is returned as an output byte array.

Parameters:

in - the byte array holding the data to be processed

inOff - the offset indicating the start position within the input byte array

inLen - the number of bytes to be processed

Returns:

the byte array containing the en/decrypted data

Throws:

BadPaddingException - if the decrypted data is not bounded by the proper padding bytes after data decryption including (un)padding

java.lang.Exception

setSecureRandom

public void setSecureRandom(java.security.SecureRandom random)

Sets the SecureRandom to be used by this Signature engine. Subclasses only may use this method to set the SecureRandom object, if required.

Overrides:

setSecureRandom in class RSACipher

Parameters:

random - the SecureRandom to be used by this signature engine

getSecureRandom

public java.security.SecureRandom getSecureRandom()

Gets the SecureRandom used by this Signature engine. If no SecureRandom has been explicitly set, a default SecureRandom is created and returned.

Overrides:

getSecureRandom in class RSACipher

Returns:

the SecureRandom used by this Signature engine

See Also:

SecRandom