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comparison dcrypt/crypto/ciphers/TEA.d @ 0:0e08791a1418

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Initial import.
author Thomas Dixon <reikon@reikon.us>
date Sun, 10 Aug 2008 14:20:17 -0400
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children 483e4467b5f6
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1 /**
2 * This file is part of the dcrypt project.
3 *
4 * Copyright: Copyright (C) dcrypt contributors 2008. All rights reserved.
5 * License: MIT
6 * Authors: Thomas Dixon
7 */
8
9 module dcrypt.crypto.ciphers.TEA;
10
11 import dcrypt.misc.Util;
12 import dcrypt.crypto.BlockCipher;
13
14 /** Implementation of the TEA cipher designed by
15 David Wheeler and Roger Needham. */
16 class TEA : BlockCipher {
17 private const uint ROUNDS = 32,
18 KEY_SIZE = 16,
19 BLOCK_SIZE = 8,
20 DELTA = 0x9e3779b9,
21 DECRYPT_SUM = 0xc6ef3720;
22 private uint sk0, sk1, sk2, sk3, sum;
23 private bool initialized,
24 encrypt;
25
26 void reset(){}
27
28 char[] name() {
29 return "TEA";
30 }
31
32 uint blockSize() {
33 return BLOCK_SIZE;
34 }
35
36 void init(bool encrypt, CipherParameters params) {
37 SymmetricKey keyParams = cast(SymmetricKey)params;
38 if (!keyParams)
39 throw new InvalidParameterError(
40 name()~": Invalid parameter passed to init");
41 this.encrypt = encrypt;
42
43 if (keyParams.key.length != KEY_SIZE)
44 throw new InvalidKeyError(
45 name()~": Invalid key length (requires 16 bytes)");
46
47 sk0 = Util.ubytesToUintBig(keyParams.key, 0);
48 sk1 = Util.ubytesToUintBig(keyParams.key, 4);
49 sk2 = Util.ubytesToUintBig(keyParams.key, 8);
50 sk3 = Util.ubytesToUintBig(keyParams.key, 12);
51
52 initialized = true;
53 }
54
55 uint processBlock(void[] input_, uint inOff, void[] output_, uint outOff) {
56 if (!initialized)
57 throw new NotInitializedError(name()~": Cipher not initialized");
58
59 ubyte[] input = cast(ubyte[]) input_;
60 ubyte[] output = cast(ubyte[]) output_;
61
62 if ((inOff + BLOCK_SIZE) > input.length)
63 throw new ShortBufferError(name()~": Input buffer too short");
64
65 if ((outOff + BLOCK_SIZE) > output.length)
66 throw new ShortBufferError(name()~": Output buffer too short");
67
68 uint v0 = Util.ubytesToUintBig(input, inOff),
69 v1 = Util.ubytesToUintBig(input, inOff+4);
70
71 sum = encrypt ? 0 : DECRYPT_SUM;
72 for (int i = 0; i < ROUNDS; i++) {
73 if (encrypt) {
74 sum += DELTA;
75 v0 += ((v1 << 4) + sk0) ^ (v1 + sum) ^ ((v1 >> 5) + sk1);
76 v1 += ((v0 << 4) + sk2) ^ (v0 + sum) ^ ((v0 >> 5) + sk3);
77 } else {
78 v1 -= ((v0 << 4) + sk2) ^ (v0 + sum) ^ ((v0 >> 5) + sk3);
79 v0 -= ((v1 << 4) + sk0) ^ (v1 + sum) ^ ((v1 >> 5) + sk1);
80 sum -= DELTA;
81 }
82 }
83
84 Util.uintToUbytesBig(v0, output, outOff);
85 Util.uintToUbytesBig(v1, output, outOff+4);
86
87 return BLOCK_SIZE;
88 }
89
90 /** Some TEA test vectors. */
91 unittest {
92 static const char[][] test_keys = [
93 "00000000000000000000000000000000",
94 "00000000000000000000000000000000",
95 "0123456712345678234567893456789a",
96 "0123456712345678234567893456789a"
97 ];
98
99 static const char[][] test_plaintexts = [
100 "0000000000000000",
101 "0102030405060708",
102 "0000000000000000",
103 "0102030405060708"
104 ];
105
106 static const char[][] test_ciphertexts = [
107 "41ea3a0a94baa940",
108 "6a2f9cf3fccf3c55",
109 "34e943b0900f5dcb",
110 "773dc179878a81c0"
111 ];
112
113
114 TEA t = new TEA();
115 foreach (uint i, char[] test_key; test_keys) {
116 ubyte[] buffer = new ubyte[t.blockSize];
117 char[] result;
118 SymmetricKey key = new SymmetricKey(Util.hexToUbytes(test_key));
119
120 // Encryption
121 t.init(true, key);
122 t.processBlock(Util.hexToUbytes(test_plaintexts[i]), 0, buffer, 0);
123 result = Util.ubytesToHex(buffer);
124 assert(result == test_ciphertexts[i],
125 t.name()~": ("~result~") != ("~test_ciphertexts[i]~")");
126
127 // Decryption
128 t.init(false, key);
129 t.processBlock(Util.hexToUbytes(test_ciphertexts[i]), 0, buffer, 0);
130 result = Util.ubytesToHex(buffer);
131 assert(result == test_plaintexts[i],
132 t.name()~": ("~result~") != ("~test_ciphertexts[i]~")");
133 }
134 }
135 }