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gnu.crypto.sig.rsa
Class EMSA_PKCS1_V1_5

java.lang.Object
  extended bygnu.crypto.sig.rsa.EMSA_PKCS1_V1_5
All Implemented Interfaces:
java.lang.Cloneable

public class EMSA_PKCS1_V1_5
extends java.lang.Object
implements java.lang.Cloneable

An implementation of the EMSA-PKCS1-V1.5 encoding scheme.

EMSA-PKCS1-V1.5 is parameterised by the choice of hash function Hash and hLen which denotes the length in octets of the hash function output.

References:

  1. Public-Key Cryptography Standards (PKCS) #1:
    RSA Cryptography Specifications Version 2.1.
    Jakob Jonsson and Burt Kaliski.

Version:
$Revision: 1.2 $

Method Summary
 java.lang.Object clone()
           
 byte[] encode(byte[] mHash, int emLen)
          Frames the hash of a message, along with an ID of the hash function in a DER sequence according to the specifications of EMSA-PKCS1-V1.5 as described in RFC-3447 (see class documentation).
static EMSA_PKCS1_V1_5 getInstance(java.lang.String mdName)
          Returns an instance of this object given a designated name of a hash function.
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

getInstance

public static final EMSA_PKCS1_V1_5 getInstance(java.lang.String mdName)

Returns an instance of this object given a designated name of a hash function.

Parameters:
mdName - the canonical name of a hash function.
Returns:
an instance of this object configured for use with the designated options.
Throws:
java.lang.UnsupportedOperationException - if the hash function is not implemented or does not have an ID listed in RFC-3447.

clone

public java.lang.Object clone()

encode

public byte[] encode(byte[] mHash,
                     int emLen)

Frames the hash of a message, along with an ID of the hash function in a DER sequence according to the specifications of EMSA-PKCS1-V1.5 as described in RFC-3447 (see class documentation).

Parameters:
mHash - the byte sequence resulting from applying the message digest algorithm Hash to the message M.
emLen - intended length in octets of the encoded message, at least tLen + 11, where tLen is the octet length of the DER encoding T of a certain value computed during the encoding operation.
Returns:
encoded message, an octet string of length emLen.
Throws:
java.lang.IllegalArgumentException - if the message is too long, or if the intended encoded message length is too short.

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