/// <summary>Decodes the given Radix64-encoded String
/// to a byte array that is filled with the decoded binary
/// data.<br></br>
/// The parameter strData has to have a checksum appended.
/// This checksum is also verified.
/// </summary>
/// <exception cref="ApplicationException">
/// An ApplicationException is thrown when the parameter strData
/// did not have a checksum appended, or if the checksum was
/// incorrect.
/// </exception>
/// <param name="strData">Radix64 encoded String</param>
/// <returns>Returns a byte array containing the decoded
/// base64 data.</returns>
/// <remarks>No remarks</remarks>
public static byte[] Decode(string strData)
{
//Get the checksum of the message
int nChecksumstart = strData.LastIndexOf('=');
string strCRC = "";
try {
strCRC = strData.Substring(nChecksumstart + 1, 4);
} catch {
throw new System.ApplicationException("The Radix64 checksum was wrong!");
}
//Strip the checksum from the real message
strData = strData.Substring(0, nChecksumstart);
byte[] bData = Convert.FromBase64String(strData);
string strShouldCRC = Radix64.CRC_Checksum(bData).Trim();
if (strShouldCRC != strCRC)
{
throw new System.ApplicationException("The Radix64 checksum was wrong!");
}
return(bData);
}
/// <summary>
/// Armors an OpenPGP Cleartextsignature.
/// </summary>
/// <param name="strMessage">The Message that has been signed. Note that it
/// must not be Dash Escaped before handing it to this function.</param>
/// <param name="strSignature">The OpenPGP signature of the given
/// message formated in Radix64.</param>
/// <returns>The armored OpenPGP cleartext signature.</returns>
public static string WrapCleartextSignature(string strMessage, string strSignature)
{
string strFinal = "-----BEGIN PGP SIGNED MESSAGE-----\r\n";
strFinal += "Hash: SHA1\r\n\r\n";
strFinal += Radix64.DashEscape(strMessage);
strFinal += "\r\n-----BEGIN PGP SIGNATURE-----\r\n";
strFinal += "Version: " + SharpPrivacyLibrary.ApplicationVersionInfos + "\r\n\r\n";
strFinal += strSignature;
strFinal += "-----END PGP SIGNATURE-----\r\n";
return(strFinal);
}
private static string CRC_Checksum(byte[] bData)
{
long crc = 0xb704ce;
byte[] bCRC = new byte[3];
for (int i = 0; i < bData.Length; i++)
{
crc = (crc << 8) ^ CRCTable[((crc >> 16) ^ bData[i]) & 0xff];
}
crc &= 0xffffff;
bCRC[0] = (byte)((crc & 0xFF0000) >> 16);
bCRC[1] = (byte)((crc & 0x00FF00) >> 8);
bCRC[2] = (byte)((crc & 0x0000FF));
return(Radix64.Encode(bCRC, false));
}
/// <summary>
/// Armors an OpenPGP Cleartextsignature.
/// </summary>
/// <param name="strMessage">The Message that has been signed. Note that it
/// must not be Dash Escaped before handing it to this function.</param>
/// <param name="bSignature">The OpenPGP signature of the given
/// message formated in binary.</param>
/// <returns>The armored OpenPGP cleartext signature.</returns>
public static string WrapCleatextSignature(string strMessage, byte[] bSignature)
{
return(WrapCleartextSignature(strMessage, Radix64.Encode(bSignature, true)));
}
/// <summary>
/// Armors a binary formated OpenPGP message.
/// </summary>
/// <param name="bKey">The OpenPGP message in binary form.</param>
/// <returns>Returns the armored OpenPGP message.</returns>
public static string WrapMessage(byte[] bMessage)
{
return(WrapMessage(Radix64.Encode(bMessage, true)));
}
/// <summary>
/// Armors an OpenPGP encoded public key.
/// </summary>
/// <param name="bKey">The public key encoded in OpenPGP format.</param>
/// <returns>Returns the armored public key.</returns>
public static string WrapPublicKey(byte[] bKey)
{
return(WrapPublicKey(Radix64.Encode(bKey, true)));
}
/// <summary>
/// Static function that makes parsing packets easy. Just give
/// a Radix64 encoded representation of a set of OpenPGP packets
/// as parameter, and the function returns an array of packets
/// that are the parsed OpenPGP packets.
/// </summary>
/// <param name="strBase64Text">A string containing the Radix64
/// representation of a set of OpenPGP packets</param>
/// <returns>Returns an array of packets</returns>
/// <remarks>No remarks</remarks>
public static Packet[] ParsePackets(string strBase64Text)
{
byte[] bData = Radix64.Decode(strBase64Text);
return(ParsePackets(bData));
}
