// WSSE Validation - 2007-04-30 - Robert Price - www.robertprice.co.uk
using System;

/// <summary>
/// Computes WSSE codes from input for validation.
/// </summary>
public static class WSSE
{

    /// <summary>
    /// Calculate the digest.
    /// </summary>
    /// <param name="password">A string with your unencrypted password.</param>
    /// <param name="nonce">The nonce the digest is to be created with as a string.</param>
    /// <param name="created">The timestamp as a string.</param>
    /// <returns>A string containing the digest.</returns>
    public static string GetDigest(string password, string nonce, string created)
    {
        return GetDigest(password, nonce, created, System.Text.Encoding.ASCII);
    }

    /// <summary>
    /// Calculate the digest.
    /// </summary>
    /// <param name="password">A string with your unencrypted password.</param>
    /// <param name="nonce">The nonce the digest is to be created with as a string.</param>
    /// <param name="created">The timestamp as a string.</param>
    /// <param name="enc">The System.Text.Encoding to use.</param>
    /// <returns>A string containing the digest.</returns>
    public static string GetDigest(string password, string nonce, string created, System.Text.Encoding enc)
    {
        byte[] noncebytes = enc.GetBytes(nonce);
        byte[] passwordbytes = enc.GetBytes(password);
        byte[] createdbytes = enc.GetBytes(created);
        return generatecode(noncebytes, passwordbytes, createdbytes);
    }

    /// <summary>
    /// Calculate the alternative digest.
    /// </summary>
    /// <param name="password">A string with your unencrypted password.</param>
    /// <param name="nonce">The nonce the digest is to be created with as a string.</param>
    /// <param name="created">The timestamp as a string.</param>
    /// <returns>A string containing the digest.</returns>
    public static string GetDigestAlt(string password, string nonce, string created)
    {
        return GetDigestAlt(password, nonce, created, System.Text.Encoding.ASCII);
    }

    /// <summary>
    /// Calculate the alternative digest.
    /// </summary>
    /// <param name="password">A string with your unencrypted password.</param>
    /// <param name="nonce">The nonce the digest is to be created with as a string.</param>
    /// <param name="created">The timestamp as a string.</param>
    /// <param name="enc">The System.Text.Encoding to use.</param>
    /// <returns>A string containing the digest.</returns>
    public static string GetDigestAlt(string password, string nonce, string created, System.Text.Encoding enc)
    {
        byte[] noncebytes = Convert.FromBase64String(nonce);
        byte[] passwordbytes = enc.GetBytes(password);
        byte[] createdbytes = enc.GetBytes(created);
        return generatecode(noncebytes, passwordbytes, createdbytes);
    }

    private static string generatecode(byte[] nonce, byte[] password, byte[] created)
    {
        byte[] code = new byte[nonce.Length + password.Length + created.Length];
        Array.Copy(nonce, code, nonce.Length);
        Array.Copy(created, 0, code, nonce.Length, created.Length);
        Array.Copy(password, 0, code, nonce.Length + created.Length, password.Length);

        System.Security.Cryptography.SHA1Managed SHhash = new System.Security.Cryptography.SHA1Managed();
        return Convert.ToBase64String(SHhash.ComputeHash(code));
    }

    /// <summary>
    /// Validates password, nonce and created create the same digest code as digest.
    /// </summary>
    /// <param name="password">A string with your unencrypted password.</param>
    /// <param name="nonce">The nonce the digest is to be created with as a string.</param>
    /// <param name="created">The timestamp as a string.</param>
    /// <param name="digest">The digest to validate the password, nonce and created strings against as a string.</param>
    /// <returns>true or false depending on wether the digest validates</returns>
    public static bool IsValid(string password, string nonce, string created, string digest)
    {
        return digest == GetDigest(password, nonce, created) || digest == GetDigestAlt(password, nonce, created);
    }

    /// <summary>
    /// Validates password, nonce and created create the same digest code as digest.
    /// </summary>
    /// <param name="password">A string with your unencrypted password.</param>
    /// <param name="nonce">The nonce the digest is to be created with as a string.</param>
    /// <param name="created">The timestamp as a string.</param>
    /// <param name="digest">The digest to validate the password, nonce and created strings against as a string.</param>
    /// <param name="enc">A System.Text.Encoding encoding.</param>
    /// <returns>true or false depending on wether the digest validates.</returns>
    public static bool IsValid(string password, string nonce, string created, string digest, System.Text.Encoding enc)
    {
        return digest == GetDigest(password, nonce, created, enc) || digest == GetDigestAlt(password, nonce, created, enc);
    }

}