/// <summary>
/// Computes a derived cryptographic key from a password according to PBKDF2
/// http://en.wikipedia.org/wiki/PBKDF2. The function will only return a derived key
/// if at least 'salt' is present in the 'extra' dictionary. The complete set of
/// attributes that can be set in 'extra':
/// salt: The salt value to be used.
/// iterations: Number of iterations of derivation algorithm to run.
/// keylen: Key length to derive.
/// </summary>
/// <param name="secret">The secret key from which to derive. </param>
/// <param name="extra"> Extra data for salting the secret. Possible key values 'salt'
/// (required, otherwise returns @secret), 'iterations' (1000 default),
/// and/or 'keylen' (32 default). </param>
/// <returns>A derived key (Base64 encoded) if a salt is provided in the extra parameter, or the
/// value of parameter 'secret' if not.</returns>
public static string DeriveKey(string secret, IDictionary <string, string> extra)
{
IWampCraChallenge adapter = CraChallenge.Create(extra);
string result = DeriveKey(secret, adapter);
return(result);
}
/// <summary>
/// Compute the authentication signature from an authentication challenge and a secret.
/// </summary>
/// <param name="authChallenge">The authentication challenge. </param>
/// <param name="authSecret">The authentication secret. </param>
/// <param name="challenge">Extra data for salting the secret.</param>
/// <returns>The authentication signature.</returns>
public static string AuthSignature(string authChallenge, string authSecret, IWampCraChallenge challenge)
{
if (authSecret == null)
{
authSecret = string.Empty;
}
authSecret = DeriveKey(authSecret, challenge);
return(Sign(authSecret, authChallenge));
}
public static string DeriveKey(string secret, IWampCraChallenge challenge)
{
if (challenge == null)
{
return(secret);
}
else
{
return(DeriveKey(secret,
challenge.Salt,
challenge.Iterations,
challenge.KeyLength));
}
}