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1.1 misho 1: /*
2: * Copyright (C) 2013 Tobias Brunner
3: * HSR Hochschule fuer Technik Rapperswil
4: *
5: * This program is free software; you can redistribute it and/or modify it
6: * under the terms of the GNU General Public License as published by the
7: * Free Software Foundation; either version 2 of the License, or (at your
8: * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
9: *
10: * This program is distributed in the hope that it will be useful, but
11: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13: * for more details.
14: */
15:
16: #include "rc2_crypter.h"
17:
18: typedef struct private_rc2_crypter_t private_rc2_crypter_t;
19:
20: #define RC2_BLOCK_SIZE 8
21:
22: #define ROL16(x, k) ({ uint16_t _x = (x); (_x << (k)) | (_x >> (16 - (k))); })
23: #define ROR16(x, k) ({ uint16_t _x = (x); (_x >> (k)) | (_x << (16 - (k))); })
24:
25: #define GET16(x) ({ u_char *_x = (x); (uint16_t)_x[0] | ((uint16_t)_x[1] << 8); })
26: #define PUT16(x, v) ({ u_char *_x = (x); uint16_t _v = (v); _x[0] = _v, _x[1] = _v >> 8; })
27:
28: /**
29: * Private data of rc2_crypter_t
30: */
31: struct private_rc2_crypter_t {
32:
33: /**
34: * Public interface
35: */
36: rc2_crypter_t public;
37:
38: /**
39: * The expanded key in 16-bit words
40: */
41: uint16_t K[64];
42:
43: /**
44: * Key size in bytes
45: */
46: size_t T;
47:
48: /**
49: * Effective key size in bits
50: */
51: size_t T1;
52: };
53:
54: /**
55: * PITABLE
56: */
57: static const u_char PITABLE[256] =
58: {
59: 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed,
60: 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d,
61: 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e,
62: 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2,
63: 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13,
64: 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32,
65: 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b,
66: 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82,
67: 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c,
68: 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc,
69: 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1,
70: 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26,
71: 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57,
72: 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03,
73: 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7,
74: 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7,
75: 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7,
76: 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a,
77: 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74,
78: 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec,
79: 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc,
80: 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39,
81: 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a,
82: 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31,
83: 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae,
84: 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9,
85: 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c,
86: 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9,
87: 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0,
88: 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e,
89: 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77,
90: 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad,
91: };
92:
93: /**
94: * Encrypt a single block of data
95: */
96: static void encrypt_block(private_rc2_crypter_t *this, u_char R[])
97: {
98: register uint16_t R0, R1, R2, R3, *Kj;
99: int rounds = 3, mix = 5;
100:
101: R0 = GET16(R);
102: R1 = GET16(R + 2);
103: R2 = GET16(R + 4);
104: R3 = GET16(R + 6);
105: Kj = &this->K[0];
106:
107: /* 5 mix, mash, 6 mix, mash, 5 mix */
108: while (TRUE)
109: {
110: /* mix */
111: R0 = ROL16(R0 + *(Kj++) + (R3 & R2) + (~R3 & R1), 1);
112: R1 = ROL16(R1 + *(Kj++) + (R0 & R3) + (~R0 & R2), 2);
113: R2 = ROL16(R2 + *(Kj++) + (R1 & R0) + (~R1 & R3), 3);
114: R3 = ROL16(R3 + *(Kj++) + (R2 & R1) + (~R2 & R0), 5);
115:
116: if (--mix == 0)
117: {
118: if (--rounds == 0)
119: {
120: break;
121: }
122: mix = (rounds == 2) ? 6 : 5;
123: /* mash */
124: R0 += this->K[R3 & 63];
125: R1 += this->K[R0 & 63];
126: R2 += this->K[R1 & 63];
127: R3 += this->K[R2 & 63];
128: }
129: }
130:
131: PUT16(R, R0);
132: PUT16(R + 2, R1);
133: PUT16(R + 4, R2);
134: PUT16(R + 6, R3);
135: }
136:
137: /**
138: * Decrypt a single block of data.
139: */
140: static void decrypt_block(private_rc2_crypter_t *this, u_char R[])
141: {
142: register uint16_t R0, R1, R2, R3, *Kj;
143: int rounds = 3, mix = 5;
144:
145: R0 = GET16(R);
146: R1 = GET16(R + 2);
147: R2 = GET16(R + 4);
148: R3 = GET16(R + 6);
149: Kj = &this->K[63];
150:
151: /* 5 r-mix, r-mash, 6 r-mix, r-mash, 5 r-mix */
152: while (TRUE)
153: {
154: /* r-mix */
155: R3 = ROR16(R3, 5);
156: R3 = R3 - *(Kj--) - (R2 & R1) - (~R2 & R0);
157: R2 = ROR16(R2, 3);
158: R2 = R2 - *(Kj--) - (R1 & R0) - (~R1 & R3);
159: R1 = ROR16(R1, 2);
160: R1 = R1 - *(Kj--) - (R0 & R3) - (~R0 & R2);
161: R0 = ROR16(R0, 1);
162: R0 = R0 - *(Kj--) - (R3 & R2) - (~R3 & R1);
163:
164: if (--mix == 0)
165: {
166: if (--rounds == 0)
167: {
168: break;
169: }
170: mix = (rounds == 2) ? 6 : 5;
171: /* r-mash */
172: R3 -= this->K[R2 & 63];
173: R2 -= this->K[R1 & 63];
174: R1 -= this->K[R0 & 63];
175: R0 -= this->K[R3 & 63];
176: }
177: }
178:
179: PUT16(R, R0);
180: PUT16(R + 2, R1);
181: PUT16(R + 4, R2);
182: PUT16(R + 6, R3);
183: }
184:
185: METHOD(crypter_t, decrypt, bool,
186: private_rc2_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *decrypted)
187: {
188: uint8_t *in, *out, *prev;
189:
190: if (data.len % RC2_BLOCK_SIZE || iv.len != RC2_BLOCK_SIZE)
191: {
192: return FALSE;
193: }
194:
195: in = data.ptr + data.len - RC2_BLOCK_SIZE;
196: out = data.ptr;
197: if (decrypted)
198: {
199: *decrypted = chunk_alloc(data.len);
200: out = decrypted->ptr;
201: }
202: out += data.len - RC2_BLOCK_SIZE;
203:
204: prev = in;
205: for (; in >= data.ptr; in -= RC2_BLOCK_SIZE, out -= RC2_BLOCK_SIZE)
206: {
207: if (decrypted)
208: {
209: memcpy(out, in, RC2_BLOCK_SIZE);
210: }
211: decrypt_block(this, out);
212: prev -= RC2_BLOCK_SIZE;
213: if (prev < data.ptr)
214: {
215: prev = iv.ptr;
216: }
217: memxor(out, prev, RC2_BLOCK_SIZE);
218: }
219: return TRUE;
220: }
221:
222: METHOD(crypter_t, encrypt, bool,
223: private_rc2_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *encrypted)
224: {
225: uint8_t *in, *out, *end, *prev;
226:
227: if (data.len % RC2_BLOCK_SIZE || iv.len != RC2_BLOCK_SIZE)
228: {
229: return FALSE;
230: }
231:
232: in = data.ptr;
233: end = data.ptr + data.len;
234: out = data.ptr;
235: if (encrypted)
236: {
237: *encrypted = chunk_alloc(data.len);
238: out = encrypted->ptr;
239: }
240:
241: prev = iv.ptr;
242: for (; in < end; in += RC2_BLOCK_SIZE, out += RC2_BLOCK_SIZE)
243: {
244: if (encrypted)
245: {
246: memcpy(out, in, RC2_BLOCK_SIZE);
247: }
248: memxor(out, prev, RC2_BLOCK_SIZE);
249: encrypt_block(this, out);
250: prev = out;
251: }
252: return TRUE;
253: }
254:
255: METHOD(crypter_t, get_block_size, size_t,
256: private_rc2_crypter_t *this)
257: {
258: return RC2_BLOCK_SIZE;
259: }
260:
261: METHOD(crypter_t, get_iv_size, size_t,
262: private_rc2_crypter_t *this)
263: {
264: return RC2_BLOCK_SIZE;
265: }
266:
267: METHOD(crypter_t, get_key_size, size_t,
268: private_rc2_crypter_t *this)
269: {
270: return this->T;
271: }
272:
273: METHOD(crypter_t, set_key, bool,
274: private_rc2_crypter_t *this, chunk_t key)
275: {
276: uint8_t L[128], T8, TM, idx;
277: int i;
278:
279: if (key.len != this->T)
280: {
281: return FALSE;
282: }
283: for (i = 0; i < key.len; i++)
284: {
285: L[i] = key.ptr[i];
286: }
287: for (; i < 128; i++)
288: {
289: idx = L[i-1] + L[i-key.len];
290: L[i] = PITABLE[idx];
291: }
292: T8 = (this->T1 + 7) / 8;
293: TM = ~(0xff << (8 - (8*T8 - this->T1)));
294: L[128-T8] = PITABLE[L[128-T8] & TM];
295: for (i = 127-T8; i >= 0; i--)
296: {
297: idx = L[i+1] ^ L[i+T8];
298: L[i] = PITABLE[idx];
299: }
300: for (i = 0; i < 64; i++)
301: {
302: this->K[i] = GET16(&L[i << 1]);
303: }
304: memwipe(L, sizeof(L));
305: return TRUE;
306: }
307:
308: METHOD(crypter_t, destroy, void,
309: private_rc2_crypter_t *this)
310: {
311: memwipe(this->K, sizeof(this->K));
312: free(this);
313: }
314:
315: /*
316: * Described in header
317: */
318: rc2_crypter_t *rc2_crypter_create(encryption_algorithm_t algo, size_t key_size)
319: {
320: private_rc2_crypter_t *this;
321: size_t effective;
322:
323: if (algo != ENCR_RC2_CBC)
324: {
325: return NULL;
326: }
327: key_size = max(1, key_size);
328: effective = RC2_EFFECTIVE_KEY_LEN(key_size);
329: key_size = min(128, RC2_KEY_LEN(key_size));
330: effective = max(1, min(1024, effective ?: key_size * 8));
331:
332: INIT(this,
333: .public = {
334: .crypter = {
335: .encrypt = _encrypt,
336: .decrypt = _decrypt,
337: .get_block_size = _get_block_size,
338: .get_iv_size = _get_iv_size,
339: .get_key_size = _get_key_size,
340: .set_key = _set_key,
341: .destroy = _destroy,
342: },
343: },
344: .T = key_size,
345: .T1 = effective,
346: );
347:
348: return &this->public;
349: }