gnu.java.security.sig.rsa
Class EME_PKCS1_V1_5
An implementation of the EME-PKCS1-V1.5 encoding and decoding methods.
EME-PKCS1-V1.5 is parameterised by the entity
k which is the
byte count of an RSA public shared modulus.
References:
- Public-Key Cryptography
Standards (PKCS) #1:
RSA Cryptography Specifications Version 2.1.
Jakob Jonsson and Burt Kaliski.
byte[] | decode(byte[] EM)- Separate the encoded message
EM into an octet string
PS consisting of nonzero octets and a message M
as:
EM = 0x00 || 0x02 || PS || 0x00 || M.
|
byte[] | encode(byte[] M)- Generates an octet string
PS of length k - mLen -
3 consisting of pseudo-randomly generated nonzero octets.
|
byte[] | encode(byte[] M, IRandom irnd)- Similar to
encode(byte[]) method, except that the source of
randomness to use for obtaining the padding bytes (an instance of
IRandom) is given as a parameter.
|
byte[] | encode(byte[] M, Random rnd)- Similar to the
encode(byte[],IRandom) method, except that the
source of randmoness is an instance of Random.
|
static EME_PKCS1_V1_5 | getInstance(int k)
|
static EME_PKCS1_V1_5 | getInstance(RSAKey key)
|
clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
decode
public byte[] decode(byte[] EM)
Separate the encoded message
EM into an octet string
PS consisting of nonzero octets and a message
M
as:
EM = 0x00 || 0x02 || PS || 0x00 || M.
If the first octet of
EM does not have hexadecimal value
0x00, if the second octet of
EM does not
have hexadecimal value
0x02, if there is no octet with
hexadecimal value
0x00 to separate
PS from
M, or if the length of
PS is less than
8 octets, output "decryption error" and stop.
EM - the designated encoded message.
- the decoded message
M framed in the designated
EM value.
IllegalArgumentException - if the length of the designated entity
EM is different than k (the length
in bytes of the public shared modulus), or if any of the
conditions described above is detected.
encode
public byte[] encode(byte[] M)
Generates an octet string
PS of length
k - mLen -
3 consisting of pseudo-randomly generated nonzero octets. The length
of
PS will be at least eight octets.
The method then concatenates
PS, the message
M,
and other padding to form an encoded message
EM of length
k octets as:
EM = 0x00 || 0x02 || PS || 0x00 || M.
This method uses a default PRNG to obtain the padding bytes.
M - the message to encode.
encode
public byte[] encode(byte[] M,
IRandom irnd) Similar to
encode(byte[]) method, except that the source of
randomness to use for obtaining the padding bytes (an instance of
IRandom) is given as a parameter.
M - the message to encode.irnd - the IRandom instance to use as a source of randomness.
encode
public byte[] encode(byte[] M,
Random rnd)M - the message to encode.rnd - the Random instance to use as a source of randomness.
EME_PKCS1_V1_5.java --
Copyright (C) 2003, 2006 Free Software Foundation, Inc.
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