com.nimbusds.srp6

Interface XRoutine

All Known Implementing Classes:

XRoutineWithUserIdentity

public interface XRoutine

Custom routine interface for computing the password key 'x'. Calculation of this value is required by the verifier 'v' generator as well as by the authenticating client session.

If you don't want to employ the default routine for computing 'x' you can use this interface to define your own. Remember to make sure that exactly the same routine is used to generate the verifier 'v' and by client authentication sessions later, else authentication will fail.

For a sample implementation see XRoutineWithUserIdentity which computes x = H(s | H(I | ":" | P))

Author:

Vladimir Dzhuvinov

Method Summary

Modifier and Type	Method and Description
BigInteger	computeX(MessageDigest digest, byte[] salt, byte[] username, byte[] password) Computes the password key 'x'.

Method Detail

computeX

BigInteger computeX(MessageDigest digest,
                    byte[] salt,
                    byte[] username,
                    byte[] password)

Computes the password key 'x'.

Tip: To convert a string to a byte array you can use String.getBytes() or String.getBytes(java.nio.charset.Charset). To convert a big integer to a byte array you can use BigInteger.toByteArray().

Parameters:

digest - The hash function 'H'. To enforce a particular hash algorithm, e.g. "SHA-1", you may perform a check that throws an IllegalArgumentException or ignore this argument altogether.

salt - The salt 's'. This is considered a mandatory argument in computation of 'x'.

username - The user identity 'I'. It may be ignored if the username is allowed to change or if a user may authenticate with multiple alternate identities, such as name and email address.

password - The user password 'P'. This is considered a mandatory argument in the computation of 'x'.

Returns:

The resulting 'x' value.