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public static Hash ( string text, |
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| text | string | String to be hashed |
| hasher | Hash algorithm with which to perform the hash | |
| encoder | (Optional) Character encoding for converting the text string to bytes | |
| return | string | |
/// <summary>
/// Decodes a data string.
/// </summary>
/// <param name="data">Data to be decoded</param>
/// <param name="secret">Secret key</param>
/// <param name="timestamp">Timestamp as an unsigned int</param>
/// <param name="offset">Offset for local key generation</param>
/// <returns>Decoded string</returns>
private static string Decode(string data, string secret, uint timestamp, int offset)
{
string md5Key = HashHelper.Hash(timestamp.ToString() + secret, HashHelper.HashType.MD5);
string decoded = string.Empty;
int length = CharsToEncode.Length;
for (int index = 0; index < data.Length; index++)
{
int decodeIndex = CharsToEncode.IndexOf(data[index]);
if (decodeIndex >= 0)
{
int newIndex = GetDecodeIndex(
Int32.Parse(md5Key.Substring((offset + index) % md5Key.Length, 1), NumberStyles.AllowHexSpecifier) * 7,
length,
decodeIndex);
decoded += (newIndex < 0) ? '?' : CharsToEncode[newIndex];
}
else
{
decoded += data[index];
}
}
return(decoded);
}
/// <summary>
/// Creates the digest portion of the ticket from the provided data.
/// </summary>
/// <param name="ticketData">Data used to create the digest</param>
/// <param name="secret">Secret key used to create the digest</param>
/// <returns>Digest string</returns>
/// <remarks>
/// The algorithm for the digest is as follows:
/// digest = MD5(digest0 + key)
/// where
/// Version 1.3: digest0 = MD5(iptstamp + key + user_id + user_data)
/// Version 2.0: digest0 = MD5(iptstamp + key + user_id + '\0' + token_list + '\0' + user_data)
/// </remarks>
private static string CreateDigest(AuthenticationTicketData ticketData, string secret)
{
if (ticketData == null)
{
return(null);
}
if (string.IsNullOrWhiteSpace(secret))
{
secret = DefaultSecret;
}
string iptStamp = CreateIPTimeStamp(ticketData.IPAddressAsInt, ticketData.UnixTimeStamp);
string digest;
const HashHelper.HashType hashType = HashHelper.HashType.MD5;
switch (ticketData.Version)
{
case "1.3":
digest = HashHelper.Hash(iptStamp + secret + ticketData.UserId + ticketData.UserData, hashType);
digest = HashHelper.Hash(digest + secret, hashType);
break;
case "2.0":
digest =
HashHelper.Hash(
iptStamp + secret + ticketData.UserId + '\0' + ticketData.TokensAsString + '\0' + ticketData.UserData, hashType);
digest = HashHelper.Hash(digest + secret, hashType);
break;
default:
throw new NotSupportedException(string.Format("Version {0} of the mod_auth_tkt algorithm is not supported",
ticketData.Version));
}
return(digest);
}
/// <summary>
/// Encodes a data string.
/// </summary>
/// <param name="data">Data to be encoded</param>
/// <param name="secret">Secret key</param>
/// <param name="timestamp">Timestamp as an unsigned int</param>
/// <param name="offset">Offset for local key generation</param>
/// <returns>Encoded string</returns>
private static string Encode(string data, string secret, uint timestamp, int offset)
{
string md5Key = HashHelper.Hash(timestamp.ToString() + secret, hashType: HashHelper.HashType.MD5);
int length = CharsToEncode.Length;
string encoded = string.Empty;
for (int index = 0; index < data.Length; index++)
{
int encodeIndex = CharsToEncode.IndexOf(data[index]);
if (encodeIndex >= 0)
{
int newIndex = (encodeIndex +
Int32.Parse(md5Key.Substring((offset + index) % md5Key.Length, 1), NumberStyles.AllowHexSpecifier) * 7) %
length;
encoded += CharsToEncode[newIndex];
}
else
{
encoded += data[index];
}
}
return(encoded);
}
