org.logi.crypto.padding
Class PadPKCS1v15

java.lang.Object
  |
  +--org.logi.crypto.padding.PadPKCS1v15

All Implemented Interfaces:

Padding

public class PadPKCS1v15

extends java.lang.Object

implements Padding

This class implements PKCS#1 v1.5 padding. Instances of it can perform padding for encryption and unpad after decryption. There are also static methods for padding of signatures.

Author:

Logi Ragnarsson (logi@logi.org)

Constructor Summary

PadPKCS1v15()

Method Summary

static byte[]	EMSA_PKCS1_v1_5(Fingerprint F, int emLen) Encoding Method for Signature with Appendix.
byte[]	pad(byte[] plaintext, int off, int len, EncryptionKey key) Pad the last, perhaps partial, block of plaintext.
byte[]	unPad(byte[] plaintext, int off, int len, DecryptionKey key) Un-pad the last block of plaintext.

Methods inherited from class java.lang.Object

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

Constructor Detail

PadPKCS1v15

public PadPKCS1v15()

Method Detail

EMSA_PKCS1_v1_5

public static byte[] EMSA_PKCS1_v1_5(Fingerprint F,
                                     int emLen)
                              throws PaddingException

Encoding Method for Signature with Appendix. PKCS#1 v1.5, section 9.2.1. Here, the message has already been hashed and we recieve the Fingerprint object F. This also specifies the hash function to use.

Parameters:

F - The fingerprint to sign.

emLen - The intended length of the encoded message.

random - The randomness source to use for generating padding bytes.

pad

public byte[] pad(byte[] plaintext,
                  int off,
                  int len,
                  EncryptionKey key)
           throws PaddingException

Pad the last, perhaps partial, block of plaintext.

Specified by:

pad in interface Padding

Parameters:

plaintext - The array holding plaintext data to pad.

off - The offset of data within plaintext array.

len - The length of data within plaintext array. This much be less than a single plaintext block.

key - The key which will be used to encrypt the block.

unPad

public byte[] unPad(byte[] plaintext,
                    int off,
                    int len,
                    DecryptionKey key)
             throws PaddingException

Un-pad the last block of plaintext.

Specified by:

unPad in interface Padding

Parameters:

padded - The array holding padded plaintext data.

off - The offset of data within padded array.

len - The length of data within padded array.

key - The key which will be used to decrypt the block.