diff options
Diffstat (limited to 'gnu/javax/crypto/key/srp6/SRP6KeyAgreement.java')
| -rw-r--r-- | gnu/javax/crypto/key/srp6/SRP6KeyAgreement.java | 113 |
1 files changed, 41 insertions, 72 deletions
diff --git a/gnu/javax/crypto/key/srp6/SRP6KeyAgreement.java b/gnu/javax/crypto/key/srp6/SRP6KeyAgreement.java index 63c981d80..b4264184e 100644 --- a/gnu/javax/crypto/key/srp6/SRP6KeyAgreement.java +++ b/gnu/javax/crypto/key/srp6/SRP6KeyAgreement.java @@ -49,98 +49,72 @@ import gnu.javax.crypto.sasl.srp.SRP; import java.math.BigInteger; /** - * <p>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:</p> - * + * 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: * <pre> - * 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) + * 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) * </pre> - * - * <p>Reference:</p> + * <p> + * Reference: * <ol> - * <li><a href="http://srp.stanford.edu/design.html">SRP Protocol Design</a><br> - * Thomas J. Wu.</li> + * <li><a href="http://srp.stanford.edu/design.html">SRP Protocol Design</a><br> + * Thomas J. Wu.</li> * </ol> */ -public abstract class SRP6KeyAgreement extends BaseKeyAgreementParty +public abstract class SRP6KeyAgreement + extends BaseKeyAgreementParty { - - // Constants and variables - // ------------------------------------------------------------------------- - public static final String SOURCE_OF_RANDOMNESS = "gnu.crypto.srp6.ka.prng"; - public static final String SHARED_MODULUS = "gnu.crypto.srp6.ka.N"; - public static final String GENERATOR = "gnu.crypto.srp6.ka.g"; - public static final String HASH_FUNCTION = "gnu.crypto.srp6.ka.H"; - public static final String USER_IDENTITY = "gnu.crypto.srp6.ka.I"; - public static final String USER_PASSWORD = "gnu.crypto.srp6.ka.p"; - public static final String HOST_PASSWORD_DB = "gnu.crypto.srp6.ka.password.db"; - protected static final BigInteger THREE = BigInteger.valueOf(3L); - protected SRP srp; - protected BigInteger N; - protected BigInteger g; - /** The shared secret key. */ protected BigInteger K; - // Constructor(s) - // ------------------------------------------------------------------------- - protected SRP6KeyAgreement() { super(Registry.SRP6_KA); } - // Class methods - // ------------------------------------------------------------------------- - - // Instance methods - // ------------------------------------------------------------------------- - - // implementation of common abstract methods in BaseKeyAGreementParty ------ - protected byte[] engineSharedSecret() throws KeyAgreementException { return Util.trim(K); @@ -148,25 +122,20 @@ public abstract class SRP6KeyAgreement extends BaseKeyAgreementParty protected void engineReset() { - // mda = null; srp = null; N = null; g = null; K = null; } - // helper methods ---------------------------------------------------------- - protected BigInteger uValue(final BigInteger A, final BigInteger B) { - // IMessageDigest hash = (IMessageDigest) mda.clone(); final IMessageDigest hash = srp.newDigest(); byte[] b; b = Util.trim(A); hash.update(b, 0, b.length); b = Util.trim(B); hash.update(b, 0, b.length); - return new BigInteger(1, hash.digest()); } } |