diff options
Diffstat (limited to 'Crypto/src/crypto/macs/VMPCMac.cs')
| -rw-r--r-- | Crypto/src/crypto/macs/VMPCMac.cs | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/Crypto/src/crypto/macs/VMPCMac.cs b/Crypto/src/crypto/macs/VMPCMac.cs new file mode 100644 index 000000000..89916355c --- /dev/null +++ b/Crypto/src/crypto/macs/VMPCMac.cs @@ -0,0 +1,173 @@ +using System; + +using Org.BouncyCastle.Crypto.Parameters; + +namespace Org.BouncyCastle.Crypto.Macs +{ + public class VmpcMac + : IMac + { + private byte g; + + private byte n = 0; + private byte[] P = null; + private byte s = 0; + + private byte[] T; + private byte[] workingIV; + + private byte[] workingKey; + + private byte x1, x2, x3, x4; + + public virtual int DoFinal(byte[] output, int outOff) + { + // Execute the Post-Processing Phase + for (int r = 1; r < 25; r++) + { + s = P[(s + P[n & 0xff]) & 0xff]; + + x4 = P[(x4 + x3 + r) & 0xff]; + x3 = P[(x3 + x2 + r) & 0xff]; + x2 = P[(x2 + x1 + r) & 0xff]; + x1 = P[(x1 + s + r) & 0xff]; + T[g & 0x1f] = (byte) (T[g & 0x1f] ^ x1); + T[(g + 1) & 0x1f] = (byte) (T[(g + 1) & 0x1f] ^ x2); + T[(g + 2) & 0x1f] = (byte) (T[(g + 2) & 0x1f] ^ x3); + T[(g + 3) & 0x1f] = (byte) (T[(g + 3) & 0x1f] ^ x4); + g = (byte) ((g + 4) & 0x1f); + + byte temp = P[n & 0xff]; + P[n & 0xff] = P[s & 0xff]; + P[s & 0xff] = temp; + n = (byte) ((n + 1) & 0xff); + } + + // Input T to the IV-phase of the VMPC KSA + for (int m = 0; m < 768; m++) + { + s = P[(s + P[m & 0xff] + T[m & 0x1f]) & 0xff]; + byte temp = P[m & 0xff]; + P[m & 0xff] = P[s & 0xff]; + P[s & 0xff] = temp; + } + + // Store 20 new outputs of the VMPC Stream Cipher input table M + byte[] M = new byte[20]; + for (int i = 0; i < 20; i++) + { + s = P[(s + P[i & 0xff]) & 0xff]; + M[i] = P[(P[(P[s & 0xff]) & 0xff] + 1) & 0xff]; + + byte temp = P[i & 0xff]; + P[i & 0xff] = P[s & 0xff]; + P[s & 0xff] = temp; + } + + Array.Copy(M, 0, output, outOff, M.Length); + Reset(); + + return M.Length; + } + + public virtual string AlgorithmName + { + get { return "VMPC-MAC"; } + } + + public virtual int GetMacSize() + { + return 20; + } + + public virtual void Init(ICipherParameters parameters) + { + if (!(parameters is ParametersWithIV)) + throw new ArgumentException("VMPC-MAC Init parameters must include an IV", "parameters"); + + ParametersWithIV ivParams = (ParametersWithIV) parameters; + KeyParameter key = (KeyParameter) ivParams.Parameters; + + if (!(ivParams.Parameters is KeyParameter)) + throw new ArgumentException("VMPC-MAC Init parameters must include a key", "parameters"); + + this.workingIV = ivParams.GetIV(); + + if (workingIV == null || workingIV.Length < 1 || workingIV.Length > 768) + throw new ArgumentException("VMPC-MAC requires 1 to 768 bytes of IV", "parameters"); + + this.workingKey = key.GetKey(); + + Reset(); + + } + + private void initKey(byte[] keyBytes, byte[] ivBytes) + { + s = 0; + P = new byte[256]; + for (int i = 0; i < 256; i++) + { + P[i] = (byte) i; + } + for (int m = 0; m < 768; m++) + { + s = P[(s + P[m & 0xff] + keyBytes[m % keyBytes.Length]) & 0xff]; + byte temp = P[m & 0xff]; + P[m & 0xff] = P[s & 0xff]; + P[s & 0xff] = temp; + } + for (int m = 0; m < 768; m++) + { + s = P[(s + P[m & 0xff] + ivBytes[m % ivBytes.Length]) & 0xff]; + byte temp = P[m & 0xff]; + P[m & 0xff] = P[s & 0xff]; + P[s & 0xff] = temp; + } + n = 0; + } + + public virtual void Reset() + { + initKey(this.workingKey, this.workingIV); + g = x1 = x2 = x3 = x4 = n = 0; + T = new byte[32]; + for (int i = 0; i < 32; i++) + { + T[i] = 0; + } + } + + public virtual void Update(byte input) + { + s = P[(s + P[n & 0xff]) & 0xff]; + byte c = (byte) (input ^ P[(P[(P[s & 0xff]) & 0xff] + 1) & 0xff]); + + x4 = P[(x4 + x3) & 0xff]; + x3 = P[(x3 + x2) & 0xff]; + x2 = P[(x2 + x1) & 0xff]; + x1 = P[(x1 + s + c) & 0xff]; + T[g & 0x1f] = (byte) (T[g & 0x1f] ^ x1); + T[(g + 1) & 0x1f] = (byte) (T[(g + 1) & 0x1f] ^ x2); + T[(g + 2) & 0x1f] = (byte) (T[(g + 2) & 0x1f] ^ x3); + T[(g + 3) & 0x1f] = (byte) (T[(g + 3) & 0x1f] ^ x4); + g = (byte) ((g + 4) & 0x1f); + + byte temp = P[n & 0xff]; + P[n & 0xff] = P[s & 0xff]; + P[s & 0xff] = temp; + n = (byte) ((n + 1) & 0xff); + } + + public virtual void BlockUpdate(byte[] input, int inOff, int len) + { + if ((inOff + len) > input.Length) + throw new DataLengthException("input buffer too short"); + + for (int i = 0; i < len; i++) + { + Update(input[i]); + } + } + } +} |