com.nimbusds.srp6.XRoutineWithUserIdentity Maven / Gradle / Ivy
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package com.nimbusds.srp6;
import java.math.BigInteger;
import java.security.MessageDigest;
/**
* Alternative routine for computing a password key x = H(s | H(I | ":" | P))
*
* Specification: RFC 5054.
*
*
This routine can be passed to the {@link SRP6VerifierGenerator} and
* {@link SRP6ClientSession} to replace the
* {@link SRP6Routines#computeX default routine} x = H(s | H(P)).
*
* @author Vladimir Dzhuvinov
*/
public class XRoutineWithUserIdentity implements XRoutine {
/**
* Computes x = H(s | H(I | ":" | P))
*
*
This method complies with the RFC 5054 recommendation, save for
* the hash algorithm which can be any (RFC 5054 recommends SHA-1).
*
* @param digest The hash function 'H'. Must not be {@code null}.
* @param salt The salt 's'. Must not be {@code null}.
* @param username The user identity 'I'. Must not be {@code null}.
* @param password The user password 'P'. Must not be {@code null}.
*
* @return The resulting 'x' value.
*/
public BigInteger computeX(final MessageDigest digest,
final byte[] salt,
final byte[] username,
final byte[] password) {
digest.update(username);
digest.update((byte)':');
digest.update(password);
byte[] output = digest.digest();
digest.update(salt);
output = digest.digest(output);
return BigIntegerUtils.bigIntegerFromBytes(output);
}
/**
* Returns a string representation of this routine algorithm.
*
* @return "H(s | H(I | ":" | P))"
*/
public String toString() {
return "H(s | H(I | \":\" | P))";
}
}