Mega Code Archive
Provides the Unix crypt() encryption algorithm
<![CDATA[
// <copyright file="UnixCrypt.cs" company="Cédric Belin">
// This sourcecode is a port from Java to C#.
// The original (Java) version was made by John Dumas and can be found at: http://www.dynamic.net.au/christos/crypt/UnixCrypt.txt
// </copyright>
// <summary>
// Implémentation de la classe <c>DigiWar.Security.Cryptography.UnixCrypt</c>.
// </summary>
// <author>$Author: cedx $</author>
// <date>$Date: 2009-09-10 19:44:34 +0200 (jeu. 10 sept. 2009) $</date>
// <version>$Revision: 1827 $</version>
using System;
using System.Linq;
using System.Text;
////
/// <summary>
/// Provides the Unix crypt() encryption algorithm.
/// </summary>
/// <remarks>
/// This class is a port from Java source. I do not understand the underlying algorithms, I just converted it to C# and it works.
/// Because I do not understand the underlying algorithms I cannot give most of the variables useful names. I have no clue what their
/// significance is. I tried to give the variable names as much meaning as possible, but the original source just called them a, b, c , etc...
///
/// A very important thing to note is that all ints in this code are UNSIGNED ints! Do not change this, ever!!! It will seriously fuckup the working
/// of this class. It uses major bitshifting and while Java gives you the >>> operator to signify a right bitshift WITHOUT setting the MSB for
/// a signed int, C# does not have this operator and will just set the new MSB for you if it happened to be set the moment you bitshifted it.
/// This is undesirable for most bitshifts and in the cases it did matter, I casted the variable back to an int. This was only required where
/// a variable was on the right-side of a bitshift operator.
/// </remarks>
internal static class UnixCrypt
{
/// <value>
/// The list with characters allowed in a Unix encrypted password.
/// It is used to randomly chose two characters for use in the encryption.
/// </value>
private const string m_encryptionSaltCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789./";
/// <value>
/// A lookup-table, presumably filled with some sort of encryption key.
/// It is used to calculate the index to the m_SPTranslationTable lookup-table.
/// </value>
private static readonly uint[] m_saltTranslation =
{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x0A, 0x0B, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A,
0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12,
0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A,
0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22,
0x23, 0x24, 0x25, 0x20, 0x21, 0x22, 0x23, 0x24,
0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C,
0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34,
0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C,
0x3D, 0x3E, 0x3F, 0x00, 0x00, 0x00, 0x00, 0x00,
};
/// <value>
/// A lookup-table.
/// It is used to calculate the index to the m_skb lookup-table.
/// </value>
private static readonly bool[] m_shifts =
{
false, false, true, true, true, true, true, true,
false, true, true, true, true, true, true, false
};
/// <value>
/// A lookup-table.
/// It is used the dynamically create the schedule lookup-table.
/// </value>
private static readonly uint[,] m_skb =
{
{
/* for C bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
0x00000000, 0x00000010, 0x20000000, 0x20000010,
0x00010000, 0x00010010, 0x20010000, 0x20010010,
0x00000800, 0x00000810, 0x20000800, 0x20000810,
0x00010800, 0x00010810, 0x20010800, 0x20010810,
0x00000020, 0x00000030, 0x20000020, 0x20000030,
0x00010020, 0x00010030, 0x20010020, 0x20010030,
0x00000820, 0x00000830, 0x20000820, 0x20000830,
0x00010820, 0x00010830, 0x20010820, 0x20010830,
0x00080000, 0x00080010, 0x20080000, 0x20080010,
0x00090000, 0x00090010, 0x20090000, 0x20090010,
0x00080800, 0x00080810, 0x20080800, 0x20080810,
0x00090800, 0x00090810, 0x20090800, 0x20090810,
0x00080020, 0x00080030, 0x20080020, 0x20080030,
0x00090020, 0x00090030, 0x20090020, 0x20090030,
0x00080820, 0x00080830, 0x20080820, 0x20080830,
0x00090820, 0x00090830, 0x20090820, 0x20090830,
},
{
/* for C bits (numbered as per FIPS 46) 7 8 10 11 12 13 */
0x00000000, 0x02000000, 0x00002000, 0x02002000,
0x00200000, 0x02200000, 0x00202000, 0x02202000,
0x00000004, 0x02000004, 0x00002004, 0x02002004,
0x00200004, 0x02200004, 0x00202004, 0x02202004,
0x00000400, 0x02000400, 0x00002400, 0x02002400,
0x00200400, 0x02200400, 0x00202400, 0x02202400,
0x00000404, 0x02000404, 0x00002404, 0x02002404,
0x00200404, 0x02200404, 0x00202404, 0x02202404,
0x10000000, 0x12000000, 0x10002000, 0x12002000,
0x10200000, 0x12200000, 0x10202000, 0x12202000,
0x10000004, 0x12000004, 0x10002004, 0x12002004,
0x10200004, 0x12200004, 0x10202004, 0x12202004,
0x10000400, 0x12000400, 0x10002400, 0x12002400,
0x10200400, 0x12200400, 0x10202400, 0x12202400,
0x10000404, 0x12000404, 0x10002404, 0x12002404,
0x10200404, 0x12200404, 0x10202404, 0x12202404,
},
{
/* for C bits (numbered as per FIPS 46) 14 15 16 17 19 20 */
0x00000000, 0x00000001, 0x00040000, 0x00040001,
0x01000000, 0x01000001, 0x01040000, 0x01040001,
0x00000002, 0x00000003, 0x00040002, 0x00040003,
0x01000002, 0x01000003, 0x01040002, 0x01040003,
0x00000200, 0x00000201, 0x00040200, 0x00040201,
0x01000200, 0x01000201, 0x01040200, 0x01040201,
0x00000202, 0x00000203, 0x00040202, 0x00040203,
0x01000202, 0x01000203, 0x01040202, 0x01040203,
0x08000000, 0x08000001, 0x08040000, 0x08040001,
0x09000000, 0x09000001, 0x09040000, 0x09040001,
0x08000002, 0x08000003, 0x08040002, 0x08040003,
0x09000002, 0x09000003, 0x09040002, 0x09040003,
0x08000200, 0x08000201, 0x08040200, 0x08040201,
0x09000200, 0x09000201, 0x09040200, 0x09040201,
0x08000202, 0x08000203, 0x08040202, 0x08040203,
0x09000202, 0x09000203, 0x09040202, 0x09040203,
},
{
/* for C bits (numbered as per FIPS 46) 21 23 24 26 27 28 */
0x00000000, 0x00100000, 0x00000100, 0x00100100,
0x00000008, 0x00100008, 0x00000108, 0x00100108,
0x00001000, 0x00101000, 0x00001100, 0x00101100,
0x00001008, 0x00101008, 0x00001108, 0x00101108,
0x04000000, 0x04100000, 0x04000100, 0x04100100,
0x04000008, 0x04100008, 0x04000108, 0x04100108,
0x04001000, 0x04101000, 0x04001100, 0x04101100,
0x04001008, 0x04101008, 0x04001108, 0x04101108,
0x00020000, 0x00120000, 0x00020100, 0x00120100,
0x00020008, 0x00120008, 0x00020108, 0x00120108,
0x00021000, 0x00121000, 0x00021100, 0x00121100,
0x00021008, 0x00121008, 0x00021108, 0x00121108,
0x04020000, 0x04120000, 0x04020100, 0x04120100,
0x04020008, 0x04120008, 0x04020108, 0x04120108,
0x04021000, 0x04121000, 0x04021100, 0x04121100,
0x04021008, 0x04121008, 0x04021108, 0x04121108,
},
{
/* for D bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
0x00000000, 0x10000000, 0x00010000, 0x10010000,
0x00000004, 0x10000004, 0x00010004, 0x10010004,
0x20000000, 0x30000000, 0x20010000, 0x30010000,
0x20000004, 0x30000004, 0x20010004, 0x30010004,
0x00100000, 0x10100000, 0x00110000, 0x10110000,
0x00100004, 0x10100004, 0x00110004, 0x10110004,
0x20100000, 0x30100000, 0x20110000, 0x30110000,
0x20100004, 0x30100004, 0x20110004, 0x30110004,
0x00001000, 0x10001000, 0x00011000, 0x10011000,
0x00001004, 0x10001004, 0x00011004, 0x10011004,
0x20001000, 0x30001000, 0x20011000, 0x30011000,
0x20001004, 0x30001004, 0x20011004, 0x30011004,
0x00101000, 0x10101000, 0x00111000, 0x10111000,
0x00101004, 0x10101004, 0x00111004, 0x10111004,
0x20101000, 0x30101000, 0x20111000, 0x30111000,
0x20101004, 0x30101004, 0x20111004, 0x30111004,
},
{
/* for D bits (numbered as per FIPS 46) 8 9 11 12 13 14 */
0x00000000, 0x08000000, 0x00000008, 0x08000008,
0x00000400, 0x08000400, 0x00000408, 0x08000408,
0x00020000, 0x08020000, 0x00020008, 0x08020008,
0x00020400, 0x08020400, 0x00020408, 0x08020408,
0x00000001, 0x08000001, 0x00000009, 0x08000009,
0x00000401, 0x08000401, 0x00000409, 0x08000409,
0x00020001, 0x08020001, 0x00020009, 0x08020009,
0x00020401, 0x08020401, 0x00020409, 0x08020409,
0x02000000, 0x0A000000, 0x02000008, 0x0A000008,
0x02000400, 0x0A000400, 0x02000408, 0x0A000408,
0x02020000, 0x0A020000, 0x02020008, 0x0A020008,
0x02020400, 0x0A020400, 0x02020408, 0x0A020408,
0x02000001, 0x0A000001, 0x02000009, 0x0A000009,
0x02000401, 0x0A000401, 0x02000409, 0x0A000409,
0x02020001, 0x0A020001, 0x02020009, 0x0A020009,
0x02020401, 0x0A020401, 0x02020409, 0x0A020409,
},
{
/* for D bits (numbered as per FIPS 46) 16 17 18 19 20 21 */
0x00000000, 0x00000100, 0x00080000, 0x00080100,
0x01000000, 0x01000100, 0x01080000, 0x01080100,
0x00000010, 0x00000110, 0x00080010, 0x00080110,
0x01000010, 0x01000110, 0x01080010, 0x01080110,
0x00200000, 0x00200100, 0x00280000, 0x00280100,
0x01200000, 0x01200100, 0x01280000, 0x01280100,
0x00200010, 0x00200110, 0x00280010, 0x00280110,
0x01200010, 0x01200110, 0x01280010, 0x01280110,
0x00000200, 0x00000300, 0x00080200, 0x00080300,
0x01000200, 0x01000300, 0x01080200, 0x01080300,
0x00000210, 0x00000310, 0x00080210, 0x00080310,
0x01000210, 0x01000310, 0x01080210, 0x01080310,
0x00200200, 0x00200300, 0x00280200, 0x00280300,
0x01200200, 0x01200300, 0x01280200, 0x01280300,
0x00200210, 0x00200310, 0x00280210, 0x00280310,
0x01200210, 0x01200310, 0x01280210, 0x01280310,
},
{
/* for D bits (numbered as per FIPS 46) 22 23 24 25 27 28 */
0x00000000, 0x04000000, 0x00040000, 0x04040000,
0x00000002, 0x04000002, 0x00040002, 0x04040002,
0x00002000, 0x04002000, 0x00042000, 0x04042000,
0x00002002, 0x04002002, 0x00042002, 0x04042002,
0x00000020, 0x04000020, 0x00040020, 0x04040020,
0x00000022, 0x04000022, 0x00040022, 0x04040022,
0x00002020, 0x04002020, 0x00042020, 0x04042020,
0x00002022, 0x04002022, 0x00042022, 0x04042022,
0x00000800, 0x04000800, 0x00040800, 0x04040800,
0x00000802, 0x04000802, 0x00040802, 0x04040802,
0x00002800, 0x04002800, 0x00042800, 0x04042800,
0x00002802, 0x04002802, 0x00042802, 0x04042802,
0x00000820, 0x04000820, 0x00040820, 0x04040820,
0x00000822, 0x04000822, 0x00040822, 0x04040822,
0x00002820, 0x04002820, 0x00042820, 0x04042820,
0x00002822, 0x04002822, 0x00042822, 0x04042822,
}
};
/// <value>
/// A lookup-table.
/// It is used to calculate two ints that are used to encrypt the password.
/// </value>
private static readonly uint[,] m_SPTranslationTable =
{
{
/* nibble 0 */
0x00820200, 0x00020000, 0x80800000, 0x80820200,
0x00800000, 0x80020200, 0x80020000, 0x80800000,
0x80020200, 0x00820200, 0x00820000, 0x80000200,
0x80800200, 0x00800000, 0x00000000, 0x80020000,
0x00020000, 0x80000000, 0x00800200, 0x00020200,
0x80820200, 0x00820000, 0x80000200, 0x00800200,
0x80000000, 0x00000200, 0x00020200, 0x80820000,
0x00000200, 0x80800200, 0x80820000, 0x00000000,
0x00000000, 0x80820200, 0x00800200, 0x80020000,
0x00820200, 0x00020000, 0x80000200, 0x00800200,
0x80820000, 0x00000200, 0x00020200, 0x80800000,
0x80020200, 0x80000000, 0x80800000, 0x00820000,
0x80820200, 0x00020200, 0x00820000, 0x80800200,
0x00800000, 0x80000200, 0x80020000, 0x00000000,
0x00020000, 0x00800000, 0x80800200, 0x00820200,
0x80000000, 0x80820000, 0x00000200, 0x80020200,
},
{
/* nibble 1 */
0x10042004, 0x00000000, 0x00042000, 0x10040000,
0x10000004, 0x00002004, 0x10002000, 0x00042000,
0x00002000, 0x10040004, 0x00000004, 0x10002000,
0x00040004, 0x10042000, 0x10040000, 0x00000004,
0x00040000, 0x10002004, 0x10040004, 0x00002000,
0x00042004, 0x10000000, 0x00000000, 0x00040004,
0x10002004, 0x00042004, 0x10042000, 0x10000004,
0x10000000, 0x00040000, 0x00002004, 0x10042004,
0x00040004, 0x10042000, 0x10002000, 0x00042004,
0x10042004, 0x00040004, 0x10000004, 0x00000000,
0x10000000, 0x00002004, 0x00040000, 0x10040004,
0x00002000, 0x10000000, 0x00042004, 0x10002004,
0x10042000, 0x00002000, 0x00000000, 0x10000004,
0x00000004, 0x10042004, 0x00042000, 0x10040000,
0x10040004, 0x00040000, 0x00002004, 0x10002000,
0x10002004, 0x00000004, 0x10040000, 0x00042000,
},
{
/* nibble 2 */
0x41000000, 0x01010040, 0x00000040, 0x41000040,
0x40010000, 0x01000000, 0x41000040, 0x00010040,
0x01000040, 0x00010000, 0x01010000, 0x40000000,
0x41010040, 0x40000040, 0x40000000, 0x41010000,
0x00000000, 0x40010000, 0x01010040, 0x00000040,
0x40000040, 0x41010040, 0x00010000, 0x41000000,
0x41010000, 0x01000040, 0x40010040, 0x01010000,
0x00010040, 0x00000000, 0x01000000, 0x40010040,
0x01010040, 0x00000040, 0x40000000, 0x00010000,
0x40000040, 0x40010000, 0x01010000, 0x41000040,
0x00000000, 0x01010040, 0x00010040, 0x41010000,
0x40010000, 0x01000000, 0x41010040, 0x40000000,
0x40010040, 0x41000000, 0x01000000, 0x41010040,
0x00010000, 0x01000040, 0x41000040, 0x00010040,
0x01000040, 0x00000000, 0x41010000, 0x40000040,
0x41000000, 0x40010040, 0x00000040, 0x01010000,
},
{
/* nibble 3 */
0x00100402, 0x04000400, 0x00000002, 0x04100402,
0x00000000, 0x04100000, 0x04000402, 0x00100002,
0x04100400, 0x04000002, 0x04000000, 0x00000402,
0x04000002, 0x00100402, 0x00100000, 0x04000000,
0x04100002, 0x00100400, 0x00000400, 0x00000002,
0x00100400, 0x04000402, 0x04100000, 0x00000400,
0x00000402, 0x00000000, 0x00100002, 0x04100400,
0x04000400, 0x04100002, 0x04100402, 0x00100000,
0x04100002, 0x00000402, 0x00100000, 0x04000002,
0x00100400, 0x04000400, 0x00000002, 0x04100000,
0x04000402, 0x00000000, 0x00000400, 0x00100002,
0x00000000, 0x04100002, 0x04100400, 0x00000400,
0x04000000, 0x04100402, 0x00100402, 0x00100000,
0x04100402, 0x00000002, 0x04000400, 0x00100402,
0x00100002, 0x00100400, 0x04100000, 0x04000402,
0x00000402, 0x04000000, 0x04000002, 0x04100400,
},
{
/* nibble 4 */
0x02000000, 0x00004000, 0x00000100, 0x02004108,
0x02004008, 0x02000100, 0x00004108, 0x02004000,
0x00004000, 0x00000008, 0x02000008, 0x00004100,
0x02000108, 0x02004008, 0x02004100, 0x00000000,
0x00004100, 0x02000000, 0x00004008, 0x00000108,
0x02000100, 0x00004108, 0x00000000, 0x02000008,
0x00000008, 0x02000108, 0x02004108, 0x00004008,
0x02004000, 0x00000100, 0x00000108, 0x02004100,
0x02004100, 0x02000108, 0x00004008, 0x02004000,
0x00004000, 0x00000008, 0x02000008, 0x02000100,
0x02000000, 0x00004100, 0x02004108, 0x00000000,
0x00004108, 0x02000000, 0x00000100, 0x00004008,
0x02000108, 0x00000100, 0x00000000, 0x02004108,
0x02004008, 0x02004100, 0x00000108, 0x00004000,
0x00004100, 0x02004008, 0x02000100, 0x00000108,
0x00000008, 0x00004108, 0x02004000, 0x02000008,
},
{
/* nibble 5 */
0x20000010, 0x00080010, 0x00000000, 0x20080800,
0x00080010, 0x00000800, 0x20000810, 0x00080000,
0x00000810, 0x20080810, 0x00080800, 0x20000000,
0x20000800, 0x20000010, 0x20080000, 0x00080810,
0x00080000, 0x20000810, 0x20080010, 0x00000000,
0x00000800, 0x00000010, 0x20080800, 0x20080010,
0x20080810, 0x20080000, 0x20000000, 0x00000810,
0x00000010, 0x00080800, 0x00080810, 0x20000800,
0x00000810, 0x20000000, 0x20000800, 0x00080810,
0x20080800, 0x00080010, 0x00000000, 0x20000800,
0x20000000, 0x00000800, 0x20080010, 0x00080000,
0x00080010, 0x20080810, 0x00080800, 0x00000010,
0x20080810, 0x00080800, 0x00080000, 0x20000810,
0x20000010, 0x20080000, 0x00080810, 0x00000000,
0x00000800, 0x20000010, 0x20000810, 0x20080800,
0x20080000, 0x00000810, 0x00000010, 0x20080010,
},
{
/* nibble 6 */
0x00001000, 0x00000080, 0x00400080, 0x00400001,
0x00401081, 0x00001001, 0x00001080, 0x00000000,
0x00400000, 0x00400081, 0x00000081, 0x00401000,
0x00000001, 0x00401080, 0x00401000, 0x00000081,
0x00400081, 0x00001000, 0x00001001, 0x00401081,
0x00000000, 0x00400080, 0x00400001, 0x00001080,
0x00401001, 0x00001081, 0x00401080, 0x00000001,
0x00001081, 0x00401001, 0x00000080, 0x00400000,
0x00001081, 0x00401000, 0x00401001, 0x00000081,
0x00001000, 0x00000080, 0x00400000, 0x00401001,
0x00400081, 0x00001081, 0x00001080, 0x00000000,
0x00000080, 0x00400001, 0x00000001, 0x00400080,
0x00000000, 0x00400081, 0x00400080, 0x00001080,
0x00000081, 0x00001000, 0x00401081, 0x00400000,
0x00401080, 0x00000001, 0x00001001, 0x00401081,
0x00400001, 0x00401080, 0x00401000, 0x00001001,
},
{
/* nibble 7 */
0x08200020, 0x08208000, 0x00008020, 0x00000000,
0x08008000, 0x00200020, 0x08200000, 0x08208020,
0x00000020, 0x08000000, 0x00208000, 0x00008020,
0x00208020, 0x08008020, 0x08000020, 0x08200000,
0x00008000, 0x00208020, 0x00200020, 0x08008000,
0x08208020, 0x08000020, 0x00000000, 0x00208000,
0x08000000, 0x00200000, 0x08008020, 0x08200020,
0x00200000, 0x00008000, 0x08208000, 0x00000020,
0x00200000, 0x00008000, 0x08000020, 0x08208020,
0x00008020, 0x08000000, 0x00000000, 0x00208000,
0x08200020, 0x08008020, 0x08008000, 0x00200020,
0x08208000, 0x00000020, 0x00200020, 0x08008000,
0x08208020, 0x00200000, 0x08200000, 0x08000020,
0x00208000, 0x00008020, 0x08008020, 0x08200000,
0x00000020, 0x08208000, 0x00208020, 0x00000000,
0x08000000, 0x08200020, 0x00008000, 0x00208020
}
};
/// <value>
/// A lookup-table filled with printable characters.
/// It is used to make sure the encrypted password contains only printable characters. It is filled with
/// ASCII characters 46 - 122 (from the dot (.) untill (including) the lowercase 'z').
/// </value>
private static readonly uint[] m_characterConversionTable =
{
0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35,
0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44,
0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C,
0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54,
0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x61, 0x62,
0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A,
0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72,
0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A
};
/// <value>
/// Marks the size of the dynamically created schedule lookup-table.
/// </value>
private const int m_desIterations = 16;
/// <summary>
/// Converts four seperate bytes into one uint.
/// </summary>
/// <param name="inputBytes">The bytes to use for the conversion.</param>
/// <param name="offset">The offset at which to start in the inputBytes buffer.</param>
/// <returns></returns>
private static uint FourBytesToInt(byte[] inputBytes, uint offset)
{
// I used an int here because the compiler would complain the stuff below would require a cast from int to uint.
// To keep the code cleaner I opted to use an int and cast it when I returned it.
int resultValue = 0;
resultValue = (inputBytes[offset++] & 0xFF);
resultValue |= (inputBytes[offset++] & 0xFF) << 8;
resultValue |= (inputBytes[offset++] & 0xFF) << 16;
resultValue |= (inputBytes[offset++]& 0xFF) << 24;
return (uint)resultValue;
}
/// <summary>
/// Converts an uint into 4 seperate bytes.
/// </summary>
/// <param name="inputInt">The uint to convert.</param>
/// <param name="outputBytes">The byte buffer into which to store the result.</param>
/// <param name="offset">The offset to start storing at in the outputBytes buffer.</param>
private static void IntToFourBytes(uint inputInt, byte[] outputBytes, uint offset)
{
outputBytes[offset++] = (byte)(inputInt & 0xFF);
outputBytes[offset++] = (byte)((inputInt >> 8) & 0xFF);
outputBytes[offset++] = (byte)((inputInt >> 16) & 0xFF);
outputBytes[offset++] = (byte)((inputInt >> 24) & 0xFF);
}
/// <summary>
/// Performs some operation on 4 uints. It's labeled PERM_OP in the original source.
/// </summary>
/// <param name="firstInt">The first uint to use.</param>
/// <param name="secondInt">The second uint to use.</param>
/// <param name="thirdInt">The third uint to use.</param>
/// <param name="fourthInt">The fourth uint to use.</param>
/// <param name="operationResults">An array of 2 uints that are the result of this operation.</param>
private static void PermOperation(uint firstInt, uint secondInt, uint thirdInt, uint fourthInt, uint[] operationResults)
{
// Because here an uint variable is at the right side of a bitshift, I needed to cast it to int. See the remarks of the class itself
// for more details.
uint tempInt = ((firstInt >> (int)thirdInt) ^ secondInt) & fourthInt;
firstInt ^= tempInt << (int)thirdInt;
secondInt ^= tempInt;
operationResults[0] = firstInt;
operationResults[1] = secondInt;
}
/// <summary>
/// Performs some operation on 3 uints. It's labeled HPERM_OP in the original source.
/// </summary>
/// <param name="firstInt">The first uint to use.</param>
/// <param name="secondInt">The second int to use.</param>
/// <param name="thirdInt">The third uint to use.</param>
/// <returns>An int that is the result of this operation.</returns>
private static uint HPermOperation(uint firstInt, int secondInt, uint thirdInt)
{
// The variable secondInt is always used to calculate the number at the right side of a
// bitshift. It is not used anywhere else, so I made the method parameter an int, to avoid
// unnecessary casting.
uint tempInt = ((firstInt << (16 - secondInt)) ^ firstInt) & thirdInt;
uint returnInt = firstInt ^ tempInt ^ (tempInt >> (16 - secondInt));
return returnInt;
}
/// <summary>
/// This method does some very complex bit manipulations.
/// </summary>
/// <param name="encryptionKey">The input data to use for the bit manipulations.</param>
/// <returns>m_desIterations * 2 number of uints that are the result of the manipulations.</returns>
private static uint[] SetDESKey(byte[] encryptionKey)
{
uint[] schedule = new uint[m_desIterations * 2];
uint firstInt = FourBytesToInt(encryptionKey, 0);
uint secondInt = FourBytesToInt(encryptionKey, 4);
uint[] operationResults = new uint[2];
PermOperation(secondInt, firstInt, 4, 0x0F0F0F0F, operationResults);
secondInt = operationResults[0];
firstInt = operationResults[1];
firstInt = HPermOperation(firstInt, -2, 0xCCCC0000);
secondInt = HPermOperation(secondInt, -2, 0xCCCC0000);
PermOperation(secondInt, firstInt, 1, 0x55555555, operationResults);
secondInt = operationResults[0];
firstInt = operationResults[1];
PermOperation(firstInt, secondInt, 8, 0x00FF00FF, operationResults);
firstInt = operationResults[0];
secondInt = operationResults[1];
PermOperation(secondInt, firstInt, 1, 0x55555555, operationResults);
secondInt = operationResults[0];
firstInt = operationResults[1];
secondInt = (((secondInt & 0xFF) << 16) | (secondInt & 0xFF00) |
((secondInt & 0xFF0000) >> 16) | ((firstInt & 0xF0000000) >> 4));
firstInt &= 0x0FFFFFFF;
bool needToShift;
uint firstSkbValue, secondSkbValue;
uint scheduleIndex = 0;
for(int index = 0; index < m_desIterations; index++)
{
needToShift = m_shifts[index];
if(needToShift)
{
firstInt = (firstInt >> 2) | (firstInt << 26);
secondInt = (secondInt >> 2) | (secondInt << 26);
}
else
{
firstInt = (firstInt >> 1) | (firstInt << 27);
secondInt = (secondInt >> 1) | (secondInt << 27);
}
firstInt &= 0x0FFFFFFF;
secondInt &= 0xFFFFFFF;
firstSkbValue = m_skb[0, firstInt & 0x3F] |
m_skb[1, ((firstInt >> 6) & 0x03) | ((firstInt >> 7) & 0x3C)] |
m_skb[2, ((firstInt >> 13) & 0x0F) | ((firstInt >> 14) & 0x30)] |
m_skb[3, ((firstInt >> 20) & 0x01) | ((firstInt >> 21) & 0x06) | ((firstInt >> 22) & 0x38)];
secondSkbValue = m_skb[4, secondInt & 0x3F] |
m_skb[5, ((secondInt >> 7) & 0x03) | ((secondInt >> 8) & 0x3C)] |
m_skb[6, (secondInt >> 15) & 0x3F] |
m_skb[7, ((secondInt >> 21) & 0x0F) | ((secondInt >> 22) & 0x30)];
schedule[scheduleIndex++] = ((secondSkbValue << 16) | (firstSkbValue & 0xFFFF)) & 0xFFFFFFFF;
firstSkbValue = ((firstSkbValue >> 16) | (secondSkbValue & 0xFFFF0000));
firstSkbValue = (firstSkbValue << 4) | (firstSkbValue >> 28);
schedule[scheduleIndex++] = firstSkbValue & 0xFFFFFFFF;
}
return schedule;
}
/// <summary>
/// This method does some bit manipulations.
/// </summary>
/// <param name="left">An input that is manipulated and then used for output.</param>
/// <param name="right">This is used for the bit manipulation.</param>
/// <param name="scheduleIndex">The index of an uint to use from the schedule array.</param>
/// <param name="firstSaltTranslator">The translated salt for the first salt character.</param>
/// <param name="secondSaltTranslator">The translated salt for the second salt character.</param>
/// <param name="schedule">The schedule arrray calculated before.</param>
/// <returns>The result of these manipulations.</returns>
private static uint DEncrypt(uint left, uint right, uint scheduleIndex, uint firstSaltTranslator, uint secondSaltTranslator, uint[] schedule)
{
uint firstInt, secondInt, thirdInt;
thirdInt = right ^ (right >> 16);
secondInt = thirdInt & firstSaltTranslator;
thirdInt = thirdInt & secondSaltTranslator;
secondInt = (secondInt ^ (secondInt << 16)) ^ right ^ schedule[scheduleIndex];
firstInt = (thirdInt ^ (thirdInt << 16)) ^ right ^ schedule[scheduleIndex+1];
firstInt = (firstInt >> 4) | (firstInt << 28);
left ^= (m_SPTranslationTable[1, firstInt & 0x3F] |
m_SPTranslationTable[3, (firstInt >> 8) & 0x3F] |
m_SPTranslationTable[5, (firstInt >> 16) & 0x3F] |
m_SPTranslationTable[7, (firstInt >> 24) & 0x3F] |
m_SPTranslationTable[0, secondInt & 0x3F] |
m_SPTranslationTable[2, (secondInt >> 8) & 0x3F] |
m_SPTranslationTable[4, (secondInt >> 16) & 0x3F] |
m_SPTranslationTable[6, (secondInt >> 24) & 0x3F]);
return left;
}
/// <summary>
/// Calculates two uints that are used to encrypt the password.
/// </summary>
/// <param name="schedule">The schedule table calculated earlier.</param>
/// <param name="firstSaltTranslator">The first translated salt character.</param>
/// <param name="secondSaltTranslator">The second translated salt character.</param>
/// <returns>2 uints in an array.</returns>
private static uint[] Body(uint[] schedule, uint firstSaltTranslator, uint secondSaltTranslator)
{
uint left = 0;
uint right = 0;
uint tempInt;
for(int index = 0; index < 25; index++)
{
for(uint secondIndex = 0; secondIndex < m_desIterations * 2; secondIndex += 4)
{
left = DEncrypt(left, right, secondIndex, firstSaltTranslator, secondSaltTranslator, schedule);
right = DEncrypt(right, left, secondIndex + 2, firstSaltTranslator, secondSaltTranslator, schedule);
}
tempInt = left;
left = right;
right = tempInt;
}
tempInt = right;
right = (left >> 1) | (left << 31);
left = (tempInt >> 1) | (tempInt << 31);
left &= 0xFFFFFFFF;
right &= 0xFFFFFFFF;
uint[] operationResults = new uint[2];
PermOperation(right, left, 1, 0x55555555, operationResults);
right = operationResults[0];
left = operationResults[1];
PermOperation(left, right, 8, 0x00FF00FF, operationResults);
left = operationResults[0];
right = operationResults[1];
PermOperation(right, left, 2, 0x33333333, operationResults);
right = operationResults[0];
left = operationResults[1];
PermOperation(left, right, 16, 0xFFFF, operationResults);
left = operationResults[0];
right = operationResults[1];
PermOperation(right, left, 4, 0x0F0F0F0F, operationResults);
right = operationResults[0];
left = operationResults[1];
uint[] singleOutputKey = new uint[2];
singleOutputKey[0] = left;
singleOutputKey[1] = right;
return singleOutputKey;
}
/// <summary>
/// Automatically generate the encryption salt (2 random printable characters for use in the encryption) and call the Crypt() method.
/// </summary>
/// <param name="textToEncrypt">The text that must be encrypted.</param>
/// <returns>The encrypted text.</returns>
public static string Crypt(string textToEncrypt)
{
Random randomGenerator = new Random();
int maxGeneratedNumber = m_encryptionSaltCharacters.Length;
int randomIndex;
StringBuilder encryptionSaltBuilder = new StringBuilder();
for(int index = 0; index < 2; index++)
{
randomIndex = randomGenerator.Next(maxGeneratedNumber);
encryptionSaltBuilder.Append(m_encryptionSaltCharacters[randomIndex]);
}
string encryptionSalt = encryptionSaltBuilder.ToString();
string encryptedString = Crypt(encryptionSalt, textToEncrypt);
return encryptedString;
}
/// <summary>
/// Encrypts the specified string using the Unix crypt algorithm.
/// </summary>
/// <param name="encryptionSalt">2 random printable characters that are used to randomize the encryption.</param>
/// <param name="textToEncrypt">The text that must be encrypted.</param>
/// <returns>The encrypted text.</returns>
public static string Crypt(string encryptionSalt, string textToEncrypt)
{
if(encryptionSalt==null) throw new ArgumentNullException("encryptionSalt");
if(textToEncrypt==null) throw new ArgumentNullException("textToEncrypt");
bool isSaltTooSmall = (encryptionSalt.Length < 2);
if(isSaltTooSmall)
{
throw new ArgumentException("The encryptionSalt must be 2 characters big.");
}
char firstSaltCharacter = encryptionSalt[0];
char secondSaltCharacter = encryptionSalt[1];
// Make sure the string builder is big enough AND filled with 13 characters (the length of the encrypted password).
// We will use the index operator to set them, but when the characters are not present, even though the string builder
// has enough capacity, it will throw an exception.
StringBuilder encryptionBuffer = new StringBuilder("*************");
encryptionBuffer[0] = firstSaltCharacter;
encryptionBuffer[1] = secondSaltCharacter;
// Use the ASCII value of the salt characters to lookup a number in the salt translation table.
uint firstSaltTranslator = m_saltTranslation[Convert.ToUInt32(firstSaltCharacter)];
uint secondSaltTranslator = m_saltTranslation[Convert.ToUInt32(secondSaltCharacter)] << 4;
// Build the first encryption key table by taking the ASCII value of every character in the text to encrypt and
// multiplying it by two. Note how the cast will not lose any information. The highest possible ASCII character
// in a password is the tilde (~), which has ASCII value 126, so the highest possible value after the
// multiplication would be 252.
byte[] encryptionKey = new byte[8];
for(int index = 0; index < encryptionKey.Length && index < textToEncrypt.Length; index++)
{
int shiftedCharacter = Convert.ToInt32(textToEncrypt[index]);
encryptionKey[index] = (byte)(shiftedCharacter << 1);
}
uint[] schedule = SetDESKey(encryptionKey);
uint[] singleOutputKey = Body(schedule, firstSaltTranslator, secondSaltTranslator);
byte[] binaryBuffer = new byte[9];
IntToFourBytes(singleOutputKey[0], binaryBuffer, 0);
IntToFourBytes(singleOutputKey[1], binaryBuffer, 4);
binaryBuffer[8] = 0;
uint binaryBufferIndex = 0;
uint passwordCharacter;
uint bitChecker = 0x80;
bool isAnyBitSet, bitCheckerOverflow;
for(int index = 2; index < 13; index++)
{
passwordCharacter = 0;
for(int secondIndex = 0; secondIndex < 6; secondIndex++)
{
passwordCharacter <<= 1;
isAnyBitSet = ((binaryBuffer[binaryBufferIndex] & bitChecker) != 0);
if(isAnyBitSet)
{
passwordCharacter |= 1;
}
bitChecker >>= 1;
bitCheckerOverflow = (bitChecker == 0);
if(bitCheckerOverflow)
{
binaryBufferIndex++;
bitChecker = 0x80;
}
// The original source had the line below, I moved it outside the compound signs, because it will overwrite the value
// a few times before incrementing the index. Where it is now it will be written only once.
// Just to be on the safe side, I keep the original line here, so I know where it originally was.
//encryptionBuffer[index] = Convert.ToChar(m_characterConversionTable[passwordCharacter]);
}
encryptionBuffer[index] = Convert.ToChar(m_characterConversionTable[passwordCharacter]);
}
return encryptionBuffer.ToString();
}
}
]]>