Package org.bouncycastle.crypto.agreement.srp

Class SRP6Client

  • public class SRP6Client
extends java.lang.Object
    Implements the client side SRP-6a protocol. Note that this class is stateful, and therefore NOT threadsafe. This implementation of SRP is based on the optimized message sequence put forth by Thomas Wu in the paper "SRP-6: Improvements and Refinements to the Secure Remote Password Protocol, 2002"

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected java.math.BigInteger a  
      protected java.math.BigInteger A  
      protected java.math.BigInteger B  
      protected Digest digest  
      protected java.math.BigInteger g  
      protected java.math.BigInteger Key  
      protected java.math.BigInteger M1  
      protected java.math.BigInteger M2  
      protected java.math.BigInteger N  
      protected java.security.SecureRandom random  
      protected java.math.BigInteger S  
      protected java.math.BigInteger u  
      protected java.math.BigInteger x  

    • Constructor Summary

      Constructors 
      Constructor Description
      SRP6Client()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.math.BigInteger calculateClientEvidenceMessage()
      Computes the client evidence message M1 using the previously received values.
      java.math.BigInteger calculateSecret​(java.math.BigInteger serverB)
      Generates the secret S given the server's credentials
      java.math.BigInteger calculateSessionKey()
      Computes the final session key as a result of the SRP successful mutual authentication To be called after verifying the server evidence message M2.
      java.math.BigInteger generateClientCredentials​(byte[] salt, byte[] identity, byte[] password)
      Generates client's credentials given the client's salt, identity and password
      void init​(java.math.BigInteger N, java.math.BigInteger g, Digest digest, java.security.SecureRandom random)
      Initialises the client to begin new authentication attempt
      void init​(SRP6GroupParameters group, Digest digest, java.security.SecureRandom random)  
      protected java.math.BigInteger selectPrivateValue()  
      boolean verifyServerEvidenceMessage​(java.math.BigInteger serverM2)
      Authenticates the server evidence message M2 received and saves it only if correct.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • N

        protected java.math.BigInteger N

      • g

        protected java.math.BigInteger g

      • a

        protected java.math.BigInteger a

      • A

        protected java.math.BigInteger A

      • B

        protected java.math.BigInteger B

      • x

        protected java.math.BigInteger x

      • u

        protected java.math.BigInteger u

      • S

        protected java.math.BigInteger S

      • M1

        protected java.math.BigInteger M1

      • M2

        protected java.math.BigInteger M2

      • Key

        protected java.math.BigInteger Key

      • digest

        protected Digest digest

      • random

        protected java.security.SecureRandom random

    • Constructor Detail

      • SRP6Client

        public SRP6Client()

    • Method Detail

      • init

        public void init​(java.math.BigInteger N,
                 java.math.BigInteger g,
                 Digest digest,
                 java.security.SecureRandom random)
        Initialises the client to begin new authentication attempt
        Parameters:
        N - The safe prime associated with the client's verifier
        g - The group parameter associated with the client's verifier
        digest - The digest algorithm associated with the client's verifier
        random - For key generation

      • generateClientCredentials

        public java.math.BigInteger generateClientCredentials​(byte[] salt,
                                                      byte[] identity,
                                                      byte[] password)
        Generates client's credentials given the client's salt, identity and password
        Parameters:
        salt - The salt used in the client's verifier.
        identity - The user's identity (eg. username)
        password - The user's password
        Returns:
        Client's public value to send to server

      • calculateSecret

        public java.math.BigInteger calculateSecret​(java.math.BigInteger serverB)
                                     throws CryptoException
        Generates the secret S given the server's credentials
        Parameters:
        serverB - The server's credentials
        Returns:
        Client's verification message for the server
        Throws:
        CryptoException - If server's credentials are invalid

      • selectPrivateValue

        protected java.math.BigInteger selectPrivateValue()

      • calculateClientEvidenceMessage

        public java.math.BigInteger calculateClientEvidenceMessage()
                                                    throws CryptoException
        Computes the client evidence message M1 using the previously received values. To be called after calculating the secret S.
        Returns:
        M1: the client side generated evidence message
        Throws:
        CryptoException

      • verifyServerEvidenceMessage

        public boolean verifyServerEvidenceMessage​(java.math.BigInteger serverM2)
                                    throws CryptoException
        Authenticates the server evidence message M2 received and saves it only if correct.
        Parameters:
        serverM2 - the server side generated evidence message
        Returns:
        A boolean indicating if the server message M2 was the expected one.
        Throws:
        CryptoException

      • calculateSessionKey

        public java.math.BigInteger calculateSessionKey()
                                         throws CryptoException
        Computes the final session key as a result of the SRP successful mutual authentication To be called after verifying the server evidence message M2.
        Returns:
        Key: the mutually authenticated symmetric session key
        Throws:
        CryptoException