gnu.javax.crypto.key.srp6
Class SRP6KeyAgreement
- IKeyAgreementParty
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
ˆ (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 = gˆx (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 = gˆa (identifies self, a = random number)
Host -> User: s, B = 3v + gˆb (sends salt, b = random number)
Both: u = H(A, B)
User: x = H(s, p) (user enters password)
User: S = (B - 3gˆx) ˆ (a + ux) (computes session key)
User: K = H(S)
Host: S = (Avˆu) ˆ b (computes session key)
Host: K = H(S)
Reference:
- SRP Protocol Design
Thomas J. Wu.
engineInit, engineProcessMessage, engineReset, engineSharedSecret, getSharedSecret, init, isComplete, name, nextRandomBytes, processMessage, reset |
clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
SRP6KeyAgreement
protected SRP6KeyAgreement()
The basic constructor. Object is special, because it has no
superclass, so there is no call to super().
SRP6KeyAgreement.java --
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