Mercurial > projects > dcrypt

comparison dcrypt/crypto/modes/CBC.d @ 23:4589f8c5eb3c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Replaced dcrypt.crypto.Util with dcrypt.misc.Bitwise and dcrypt.misc.ByteConverter. Altered all dependent files to reflect changes.
author Thomas Dixon <reikon@reikon.us>
date Sat, 14 Feb 2009 19:58:20 -0500
parents 8c7f8fecdd75
children 176c933827a8
comparison
equal deleted inserted replaced
22:74303a717032 23:4589f8c5eb3c
11 import dcrypt.crypto.BlockCipher; 11 import dcrypt.crypto.BlockCipher;
12 public import dcrypt.crypto.params.ParametersWithIV; 12 public import dcrypt.crypto.params.ParametersWithIV;
13 13
14 version (UnitTest) { 14 version (UnitTest) {
15 import dcrypt.crypto.ciphers.XTEA; 15 import dcrypt.crypto.ciphers.XTEA;
16 import dcrypt.misc.Util; 16 import dcrypt.misc.ByteConverter;
17 } 17 }
18 18
19 /** This class implements the cipher block chaining (CBC) block mode. */ 19 /** This class implements the cipher block chaining (CBC) block mode. */
20 class CBC : BlockCipher { 20 class CBC : BlockCipher {
21 private BlockCipher m_cipher; 21 private BlockCipher wrappedCipher;
22 private ubyte[] iv, 22 private ubyte[] iv,
23 previousCiphertext, 23 previousCiphertext,
24 cbcOutput; 24 cbcOutput;
25 private bool encrypt, 25 private bool encrypt,
26 initialized; 26 initialized;
28 /** 28 /**
29 * Params: 29 * Params:
30 * cipher = Block cipher to wrap. 30 * cipher = Block cipher to wrap.
31 */ 31 */
32 this (BlockCipher cipher) { 32 this (BlockCipher cipher) {
33 m_cipher = cipher; 33 wrappedCipher = cipher;
34 } 34 }
35 35
36 /** Returns: The underlying cipher we are wrapping. */ 36 /** Returns: The underlying cipher we are wrapping. */
37 BlockCipher cipher() { 37 BlockCipher cipher() {
38 return m_cipher; 38 return wrappedCipher;
39 } 39 }
40 40
41 char[] name() { 41 char[] name() {
42 return m_cipher.name~"/CBC"; 42 return wrappedCipher.name~"/CBC";
43 } 43 }
44 44
45 /** 45 /**
46 * Throws: dcrypt.crypto.errors.InvalidParameterError if params aren't 46 * Throws: dcrypt.crypto.errors.InvalidParameterError if params aren't
47 * an instance of dcrypt.crypto.params.ParametersWithIV. 47 * an instance of dcrypt.crypto.params.ParametersWithIV.
48 */ 48 */
49 void init(bool encrypt, CipherParameters params) { 49 void init(bool encrypt, CipherParameters params) {
50 ParametersWithIV ivParams = cast(ParametersWithIV)params; 50 ParametersWithIV ivParams = cast(ParametersWithIV)params;
51 51
52 if (!ivParams) 52 if (!ivParams)
55 if (ivParams.iv.length != blockSize) 55 if (ivParams.iv.length != blockSize)
56 throw new InvalidParameterError( 56 throw new InvalidParameterError(
57 name()~": IV must be same length as cipher block size"); 57 name()~": IV must be same length as cipher block size");
58 58
59 this.encrypt = encrypt; 59 this.encrypt = encrypt;
60 m_cipher.init(encrypt, ivParams.parameters); 60 wrappedCipher.init(encrypt, ivParams.parameters);
61 61
62 iv = ivParams.iv[0..blockSize]; 62 iv = ivParams.iv[0..blockSize];
63 previousCiphertext = new ubyte[blockSize]; 63 previousCiphertext = new ubyte[blockSize];
64 previousCiphertext[] = iv; // C_0 = IV 64 previousCiphertext[] = iv; // C_0 = IV
65 cbcOutput = new ubyte[blockSize]; // Output buffer for E_k/D_k(...) 65 cbcOutput = new ubyte[blockSize]; // Output buffer for E_k/D_k(...)
85 // P_i XOR C_i-1 85 // P_i XOR C_i-1
86 for (int i = 0; i < blockSize; i++) 86 for (int i = 0; i < blockSize; i++)
87 previousCiphertext[i] ^= input[i]; 87 previousCiphertext[i] ^= input[i];
88 88
89 // E_k(P_i XOR C_i-1) 89 // E_k(P_i XOR C_i-1)
90 m_cipher.update(previousCiphertext, cbcOutput); 90 wrappedCipher.update(previousCiphertext, cbcOutput);
91 91
92 // Store C_i for next block 92 // Store C_i for next block
93 previousCiphertext[] = cbcOutput; 93 previousCiphertext[] = cbcOutput;
94 94
95 // C_i = E_k(P_i XOR C_i-1) 95 // C_i = E_k(P_i XOR C_i-1)
97 } else { 97 } else {
98 // Temporarily store C_i 98 // Temporarily store C_i
99 ubyte[] t = input[0..blockSize]; 99 ubyte[] t = input[0..blockSize];
100 100
101 // D_k(C_i) 101 // D_k(C_i)
102 m_cipher.update(t, cbcOutput); 102 wrappedCipher.update(t, cbcOutput);
103 103
104 // P_i = D_k(C_i) XOR C_i-1 104 // P_i = D_k(C_i) XOR C_i-1
105 for (int i = 0; i < blockSize; i++) 105 for (int i = 0; i < blockSize; i++)
106 output[i] = (cbcOutput[i] ^ previousCiphertext[i]); 106 output[i] = (cbcOutput[i] ^ previousCiphertext[i]);
107 107
111 111
112 return blockSize; 112 return blockSize;
113 } 113 }
114 114
115 uint blockSize() { 115 uint blockSize() {
116 return m_cipher.blockSize; 116 return wrappedCipher.blockSize;
117 } 117 }
118 118
119 void reset() { 119 void reset() {
120 previousCiphertext[] = iv; 120 previousCiphertext[] = iv;
121 m_cipher.reset(); 121 wrappedCipher.reset();
122 } 122 }
123 123
124 /** Test vectors for CBC mode. Assumes XTEA passes test vectors. */ 124 /** Test vectors for CBC mode. Assumes XTEA passes test vectors. */
125 version (UnitTest) { 125 version (UnitTest) {
126 unittest { 126 unittest {
156 CBC c = new CBC(x); 156 CBC c = new CBC(x);
157 ubyte[] iv = new ubyte[x.blockSize], // Initialized to 0 157 ubyte[] iv = new ubyte[x.blockSize], // Initialized to 0
158 buffer = new ubyte[32]; 158 buffer = new ubyte[32];
159 char[] result; 159 char[] result;
160 for (int i = 0; i < test_keys.length; i++) { 160 for (int i = 0; i < test_keys.length; i++) {
161 SymmetricKey key = new SymmetricKey(Util.hexToUbytes(test_keys[i])); 161 SymmetricKey key = new SymmetricKey(ByteConverter.hexDecode(test_keys[i]));
162 ParametersWithIV params = new ParametersWithIV(key, iv); 162 ParametersWithIV params = new ParametersWithIV(key, iv);
163 163
164 // Encryption 164 // Encryption
165 c.init(true, params); 165 c.init(true, params);
166 for (int j = 0; j < 32; j+=x.blockSize) 166 for (int j = 0; j < 32; j+=x.blockSize)
167 c.update(Util.hexToUbytes(test_plaintexts[i])[j..j+x.blockSize], buffer[j..j+x.blockSize]); 167 c.update(ByteConverter.hexDecode(test_plaintexts[i])[j..j+x.blockSize], buffer[j..j+x.blockSize]);
168 result = Util.ubytesToHex(buffer); 168 result = ByteConverter.hexEncode(buffer);
169 assert(result == test_ciphertexts[i], 169 assert(result == test_ciphertexts[i],
170 c.name()~": ("~result~") != ("~test_ciphertexts[i]~")"); 170 c.name()~": ("~result~") != ("~test_ciphertexts[i]~")");
171 171
172 // Decryption 172 // Decryption
173 c.init(false, params); 173 c.init(false, params);
174 for (int j = 0; j < 32; j+=x.blockSize) 174 for (int j = 0; j < 32; j+=x.blockSize)
175 c.update(Util.hexToUbytes(test_ciphertexts[i])[j..j+x.blockSize], buffer[j..j+x.blockSize]); 175 c.update(ByteConverter.hexDecode(test_ciphertexts[i])[j..j+x.blockSize], buffer[j..j+x.blockSize]);
176 result = Util.ubytesToHex(buffer); 176 result = ByteConverter.hexEncode(buffer);
177 assert(result == test_plaintexts[i], 177 assert(result == test_plaintexts[i],
178 c.name()~": ("~result~") != ("~test_plaintexts[i]~")"); 178 c.name()~": ("~result~") != ("~test_plaintexts[i]~")");
179 } 179 }
180 } 180 }
181 } 181 }