/// <summary> /// Takes a time step and computes a TOTP code /// </summary> /// <param name="counter">time step</param> /// <param name="mode">The hash mode to use</param> /// <returns>TOTP calculated code</returns> protected override string Compute(long counter, OtpHashMode mode) { var data = KeyUtilities.GetBigEndianBytes(counter); var otp = CalculateOtp(data, mode); return(Digits(otp, totpSize)); }
/// <summary> /// Uses the procedure defined in RFC 4226 section 7.5 to derive a key from the master key /// </summary> /// <param name="masterKey">The master key from which to derive a device specific key</param> /// <param name="serialNumber">A serial number that is unique to the authenticating device</param> /// <param name="mode">The hash mode to use. This will determine the resulting key lenght. The default is sha-1 (as per the RFC) which is 20 bytes</param> /// <returns>Derived key</returns> public static byte[] DeriveKeyFromMaster(IKeyProvider masterKey, int serialNumber, OtpHashMode mode = OtpHashMode.Sha1) { return(DeriveKeyFromMaster(masterKey, KeyUtilities.GetBigEndianBytes(serialNumber), mode)); }