gnu.crypto.key.srp6
Class SRP6KeyAgreement
- IKeyAgreementParty
public abstract class SRP6KeyAgreement
The Secure Remote Password (SRP) key agreement protocol, also known as
SRP-6, is designed by Thomas J. Wu (see references). The protocol, and its
elements are described as follows:
N A large safe prime (N = 2q+1, where q is prime)
All arithmetic is done modulo N.
g A generator modulo N
s User's salt
I Username
p Cleartext Password
H() One-way hash function
^ (Modular) Exponentiation
u Random scrambling parameter
a,b Secret ephemeral values
A,B Public ephemeral values
x Private key (derived from p and s)
v Password verifier
The host stores passwords using the following formula:
x = H(s | H(I ":" p)) (s is chosen randomly)
v = g^x (computes password verifier)
The host then keeps {I, s, v} in its password database.
The authentication protocol itself goes as follows:
User -> Host: I, A = g^a (identifies self, a = random number)
Host -> User: s, B = 3v + g^b (sends salt, b = random number)
Both: u = H(A, B)
User: x = H(s, p) (user enters password)
User: S = (B - 3g^x) ^ (a + ux) (computes session key)
User: K = H(S)
Host: S = (Av^u) ^ b (computes session key)
Host: K = H(S)
Reference:
- SRP Protocol Design
Thomas J. Wu.
Version:
engineInit , engineProcessMessage , engineReset , engineSharedSecret , getSharedSecret , init , isComplete , name , nextRandomBytes , processMessage , reset |
GENERATOR
public static final String GENERATOR
HASH_FUNCTION
public static final String HASH_FUNCTION
HOST_PASSWORD_DB
public static final String HOST_PASSWORD_DB
K
protected BigInteger K
The shared secret key.
SHARED_MODULUS
public static final String SHARED_MODULUS
SOURCE_OF_RANDOMNESS
public static final String SOURCE_OF_RANDOMNESS
THREE
protected static final BigInteger THREE
USER_IDENTITY
public static final String USER_IDENTITY
USER_PASSWORD
public static final String USER_PASSWORD
SRP6KeyAgreement
protected SRP6KeyAgreement()
uValue
protected BigInteger uValue(BigInteger A,
BigInteger B)
Copyright © 2001, 2002, 2003
Free Software Foundation,
Inc. All Rights Reserved.