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54482987 MW |
1 | #! /usr/bin/python |
2 | ### -*-python-*- | |
3 | ### | |
4 | ### Generalization of OCB mode for other block sizes | |
5 | ### | |
6 | ### (c) 2017 Mark Wooding | |
7 | ### | |
8 | ||
9 | ###----- Licensing notice --------------------------------------------------- | |
10 | ### | |
11 | ### This program is free software; you can redistribute it and/or modify | |
12 | ### it under the terms of the GNU General Public License as published by | |
13 | ### the Free Software Foundation; either version 2 of the License, or | |
14 | ### (at your option) any later version. | |
15 | ### | |
16 | ### This program is distributed in the hope that it will be useful, | |
17 | ### but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ### GNU General Public License for more details. | |
20 | ### | |
21 | ### You should have received a copy of the GNU General Public License | |
22 | ### along with this program; if not, write to the Free Software Foundation, | |
23 | ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
24 | ||
25 | from sys import argv, stderr | |
26 | from struct import pack | |
27 | from itertools import izip | |
86082bbc | 28 | from contextlib import contextmanager |
54482987 MW |
29 | import catacomb as C |
30 | ||
31 | R = C.FibRand(0) | |
32 | ||
33 | ###-------------------------------------------------------------------------- | |
34 | ### Utilities. | |
35 | ||
36 | def combs(things, k): | |
37 | ii = range(k) | |
38 | n = len(things) | |
39 | while True: | |
40 | yield [things[i] for i in ii] | |
41 | for j in xrange(k): | |
42 | if j == k - 1: lim = n | |
43 | else: lim = ii[j + 1] | |
44 | i = ii[j] + 1 | |
45 | if i < lim: | |
46 | ii[j] = i | |
47 | break | |
48 | ii[j] = j | |
49 | else: | |
50 | return | |
51 | ||
52 | POLYMAP = {} | |
53 | ||
54 | def poly(nbits): | |
55 | try: return POLYMAP[nbits] | |
56 | except KeyError: pass | |
57 | base = C.GF(0).setbit(nbits).setbit(0) | |
58 | for k in xrange(1, nbits, 2): | |
59 | for cc in combs(range(1, nbits), k): | |
60 | p = base + sum(C.GF(0).setbit(c) for c in cc) | |
61 | if p.irreduciblep(): POLYMAP[nbits] = p; return p | |
62 | raise ValueError, nbits | |
63 | ||
64 | def prim(nbits): | |
65 | ## No fancy way to do this: I'd need a much cleverer factoring algorithm | |
66 | ## than I have in my pockets. | |
67 | if nbits == 64: cc = [64, 4, 3, 1, 0] | |
68 | elif nbits == 96: cc = [96, 10, 9, 6, 0] | |
69 | elif nbits == 128: cc = [128, 7, 2, 1, 0] | |
70 | elif nbits == 192: cc = [192, 15, 11, 5, 0] | |
71 | elif nbits == 256: cc = [256, 10, 5, 2, 0] | |
72 | else: raise ValueError, 'no field for %d bits' % nbits | |
73 | p = C.GF(0) | |
74 | for c in cc: p = p.setbit(c) | |
75 | return p | |
76 | ||
77 | def Z(n): | |
78 | return C.ByteString.zero(n) | |
79 | ||
80 | def mul_blk_gf(m, x, p): return ((C.GF.loadb(m)*x)%p).storeb((p.nbits + 6)/8) | |
81 | ||
82 | def with_lastp(it): | |
83 | it = iter(it) | |
84 | try: j = next(it) | |
85 | except StopIteration: raise ValueError, 'empty iter' | |
86 | lastp = False | |
87 | while not lastp: | |
88 | i = j | |
89 | try: j = next(it) | |
90 | except StopIteration: lastp = True | |
91 | yield i, lastp | |
92 | ||
93 | def safehex(x): | |
94 | if len(x): return hex(x) | |
95 | else: return '""' | |
96 | ||
97 | def keylens(ksz): | |
98 | sel = [] | |
99 | if isinstance(ksz, C.KeySZSet): kk = ksz.set | |
100 | elif isinstance(ksz, C.KeySZRange): kk = range(ksz.min, ksz.max, ksz.mod) | |
101 | elif isinstance(ksz, C.KeySZAny): kk = range(64); sel = [0] | |
102 | kk = list(kk); kk = kk[:] | |
103 | n = len(kk) | |
104 | while n and len(sel) < 4: | |
105 | i = R.range(n) | |
106 | n -= 1 | |
107 | kk[i], kk[n] = kk[n], kk[i] | |
108 | sel.append(kk[n]) | |
109 | return sel | |
110 | ||
111 | def pad0star(m, w): | |
112 | n = len(m) | |
113 | if not n: r = w | |
114 | else: r = (-len(m))%w | |
115 | if r: m += Z(r) | |
116 | return C.ByteString(m) | |
117 | ||
118 | def pad10star(m, w): | |
119 | r = w - len(m)%w | |
120 | if r: m += '\x80' + Z(r - 1) | |
121 | return C.ByteString(m) | |
122 | ||
123 | def ntz(i): | |
124 | j = 0 | |
125 | while (i&1) == 0: i >>= 1; j += 1 | |
126 | return j | |
127 | ||
128 | def blocks(x, w): | |
129 | v, i, n = [], 0, len(x) | |
130 | while n - i > w: | |
131 | v.append(C.ByteString(x[i:i + w])) | |
132 | i += w | |
133 | return v, C.ByteString(x[i:]) | |
134 | ||
135 | EMPTY = C.bytes('') | |
136 | ||
137 | def blocks0(x, w): | |
138 | v, tl = blocks(x, w) | |
139 | if len(tl) == w: v.append(tl); tl = EMPTY | |
140 | return v, tl | |
141 | ||
142 | ###-------------------------------------------------------------------------- | |
143 | ### Luby--Rackoff large-block ciphers. | |
144 | ||
145 | class LubyRackoffCipher (type): | |
146 | def __new__(cls, bc, blksz): | |
147 | assert blksz%2 == 0 | |
148 | assert blksz <= 2*bc.blksz | |
149 | name = '%s-lr[%d]' % (bc.name, 8*blksz) | |
150 | me = type(name, (LubyRackoffBase,), {}) | |
151 | me.name = name | |
152 | me.blksz = blksz | |
153 | me.keysz = bc.keysz | |
154 | me.bc = bc | |
155 | return me | |
156 | ||
86082bbc MW |
157 | @contextmanager |
158 | def muffle(): | |
159 | global VERBOSE, LRVERBOSE | |
160 | _v, _lrv = VERBOSE, LRVERBOSE | |
161 | try: | |
162 | VERBOSE = LRVERBOSE = False | |
163 | yield None | |
164 | finally: | |
165 | VERBOSE, LRVERBOSE = _v, _lrv | |
166 | ||
54482987 MW |
167 | class LubyRackoffBase (object): |
168 | NR = 4 # for strong-PRP security | |
169 | def __init__(me, k): | |
170 | if LRVERBOSE: print 'K = %s' % hex(k) | |
171 | bc, blksz = me.__class__.bc, me.__class__.blksz | |
86082bbc | 172 | with muffle(): E = bc(k) |
54482987 MW |
173 | me.f = [] |
174 | ksz = len(k) | |
175 | i = C.MP(0) | |
176 | for j in xrange(me.NR): | |
177 | b = C.WriteBuffer() | |
178 | while b.size < ksz: | |
86082bbc | 179 | with muffle(): x = E.encrypt(i.storeb(bc.blksz)) |
54482987 MW |
180 | b.put(x) |
181 | if LRVERBOSE: print 'E(K; [%d]) = %s' % (i, hex(x)) | |
182 | i += 1 | |
183 | kj = C.ByteString(C.ByteString(b)[0:ksz]) | |
184 | if LRVERBOSE: print 'K_%d = %s' % (j, hex(kj)) | |
86082bbc | 185 | with muffle(): me.f.append(bc(kj)) |
54482987 MW |
186 | def encrypt(me, m): |
187 | bc, blksz = me.__class__.bc, me.__class__.blksz | |
188 | assert len(m) == blksz | |
189 | l, r = C.ByteString(m[:blksz/2]), C.ByteString(m[blksz/2:]) | |
190 | if LRVERBOSE: print 'L_0, R_0 = %s, %s' % (hex(l), hex(r)) | |
191 | for j in xrange(me.NR): | |
192 | l0 = pad0star(l, bc.blksz) | |
86082bbc | 193 | with muffle(): t = me.f[j].encrypt(l0) |
54482987 MW |
194 | l, r = r ^ t[:blksz/2], l |
195 | if LRVERBOSE: | |
196 | print 'E(K_%d; L_%d || 0^*) = %s' % (j, j, hex(t)) | |
197 | print 'L_%d, R_%d = %s, %s' % (j + 1, j + 1, hex(l), hex(r)) | |
198 | return C.ByteString(r + l) | |
199 | def decrypt(me, c): | |
200 | bc, blksz = me.__class__.bc, me.__class__.blksz | |
201 | assert len(c) == blksz | |
202 | l, r = C.ByteString(c[:blksz/2]), C.ByteString(c[blksz/2:]) | |
203 | for j in xrange(me.NR - 1, -1, -1): | |
204 | l0 = pad0star(l, bc.blksz) | |
86082bbc | 205 | with muffle(): t = me.f[j].encrypt(l0) |
54482987 MW |
206 | if LRVERBOSE: |
207 | print 'L_%d, R_%d = %s, %s' % (j + 1, j + 1, hex(l), hex(r)) | |
208 | print 'E(K_%d; L_%d || 0^*) = %s' % (j + 1, j + 1, hex(t)) | |
209 | l, r = r ^ t[:blksz/2], l | |
210 | if LRVERBOSE: print 'L_0, R_0 = %s, %s' % (hex(l), hex(r)) | |
211 | return C.ByteString(r + l) | |
212 | ||
213 | LRAES = {} | |
214 | for i in [8, 12, 16, 24, 32]: | |
215 | LRAES['lraes%d' % (8*i)] = LubyRackoffCipher(C.rijndael, i) | |
86082bbc | 216 | LRAES['dlraes512'] = LubyRackoffCipher(LubyRackoffCipher(C.rijndael, 32), 64) |
54482987 MW |
217 | |
218 | ###-------------------------------------------------------------------------- | |
219 | ### PMAC. | |
220 | ||
221 | def ocb_masks(E): | |
222 | blksz = E.__class__.blksz | |
223 | p = poly(8*blksz) | |
224 | x = C.GF(2); xinv = p.modinv(x) | |
225 | z = Z(blksz) | |
226 | L = E.encrypt(z) | |
227 | Lxinv = mul_blk_gf(L, xinv, p) | |
228 | Lgamma = 66*[L] | |
229 | for i in xrange(1, len(Lgamma)): | |
230 | Lgamma[i] = mul_blk_gf(Lgamma[i - 1], x, p) | |
231 | return Lgamma, Lxinv | |
232 | ||
233 | def dump_ocb(E): | |
234 | Lgamma, Lxinv = ocb_masks(E) | |
235 | print 'L x^-1 = %s' % hex(Lxinv) | |
236 | for i, lg in enumerate(Lgamma): | |
237 | print 'L x^%d = %s' % (i, hex(lg)) | |
238 | ||
239 | def pmac1(E, m): | |
240 | blksz = E.__class__.blksz | |
241 | Lgamma, Lxinv = ocb_masks(E) | |
242 | a = o = Z(blksz) | |
243 | i = 1 | |
244 | v, tl = blocks(m, blksz) | |
245 | for x in v: | |
246 | b = ntz(i) | |
247 | o ^= Lgamma[b] | |
248 | a ^= E.encrypt(x ^ o) | |
249 | if VERBOSE: | |
250 | print 'Z[%d]: %d -> %s' % (i - 1, b, hex(o)) | |
251 | print 'A[%d]: %s' % (i - 1, hex(a)) | |
252 | i += 1 | |
253 | if len(tl) == blksz: a ^= tl ^ Lxinv | |
254 | else: a ^= pad10star(tl, blksz) | |
255 | return E.encrypt(a) | |
256 | ||
257 | def pmac2(E, m): | |
258 | blksz = E.__class__.blksz | |
259 | p = prim(8*blksz) | |
260 | L = E.encrypt(Z(blksz)) | |
261 | o = mul_blk_gf(L, 10, p) | |
262 | a = Z(blksz) | |
263 | v, tl = blocks(m, blksz) | |
264 | for x in v: | |
265 | a ^= E.encrypt(x ^ o) | |
266 | o = mul_blk_gf(o, 2, p) | |
267 | if len(tl) == blksz: a ^= tl ^ mul_blk_gf(o, 3, p) | |
268 | else: a ^= pad10star(tl, blksz) ^ mul_blk_gf(o, 5, p) | |
269 | return E.encrypt(a) | |
270 | ||
271 | def ocb3_masks(E): | |
272 | Lgamma, _ = ocb_masks(E) | |
273 | Lstar = Lgamma[0] | |
274 | Ldollar = Lgamma[1] | |
275 | return Lstar, Ldollar, Lgamma[2:] | |
276 | ||
277 | def dump_ocb3(E): | |
278 | Lstar, Ldollar, Lgamma = ocb3_masks(E) | |
279 | print 'L_* : %s' % hex(Lstar) | |
280 | print 'L_$ : %s' % hex(Ldollar) | |
281 | for i, lg in enumerate(Lgamma[:4]): | |
282 | print 'L_%-8d: %s' % (i, hex(lg)) | |
283 | ||
284 | def pmac3(E, m): | |
285 | blksz = E.__class__.blksz | |
286 | Lstar, Ldollar, Lgamma = ocb3_masks(E) | |
287 | a = o = Z(blksz) | |
288 | i = 1 | |
289 | v, tl = blocks0(m, blksz) | |
290 | for x in v: | |
291 | b = ntz(i) | |
292 | o ^= Lgamma[b] | |
293 | a ^= E.encrypt(x ^ o) | |
294 | if VERBOSE: | |
295 | print 'Offset\'_%-2d: %s' % (i, hex(o)) | |
296 | print 'AuthSum_%-2d: %s' % (i, hex(a)) | |
297 | i += 1 | |
298 | if tl: | |
299 | o ^= Lstar | |
300 | a ^= E.encrypt(pad10star(tl, blksz) ^ o) | |
301 | if VERBOSE: | |
302 | print 'Offset\'_* : %s' % hex(o) | |
303 | print 'AuthSum_* : %s' % hex(a) | |
304 | return a | |
305 | ||
306 | def pmac1_pub(E, m): | |
307 | if VERBOSE: dump_ocb(E) | |
308 | return pmac1(E, m), | |
309 | ||
310 | def pmac2_pub(E, m): | |
311 | return pmac2(E, m), | |
312 | ||
313 | def pmac3_pub(E, m): | |
314 | return pmac3(E, m), | |
315 | ||
316 | def pmacgen(bc): | |
317 | return [(0,), (1,), | |
318 | (3*bc.blksz,), | |
319 | (3*bc.blksz - 5,)] | |
320 | ||
321 | ###-------------------------------------------------------------------------- | |
322 | ### OCB. | |
323 | ||
324 | ## For OCB2, it's important for security that n = log_x (x + 1) is large in | |
325 | ## the field representations of GF(2^w) used -- in fact, we need more, that | |
326 | ## i n (mod 2^w - 1) is large for i in {4, -3, -2, -1, 1, 2, 3, 4}. The | |
327 | ## original paper lists the values for 64 and 128, but we support other block | |
328 | ## sizes, so here's the result of the (rather large, in some cases) | |
329 | ## computation. | |
330 | ## | |
331 | ## Block size log_x (x + 1) | |
332 | ## | |
333 | ## 64 9686038906114705801 | |
334 | ## 96 63214690573408919568138788065 | |
335 | ## 128 338793687469689340204974836150077311399 | |
336 | ## 192 161110085006042185925119981866940491651092686475226538785 | |
337 | ## 256 22928580326165511958494515843249267194111962539778797914076675796261938307298 | |
338 | ||
339 | def ocb1(E, n, h, m, tsz = None): | |
340 | ## This is OCB1.PMAC1 from Rogaway's `Authenticated-Encryption with | |
341 | ## Associated-Data'. | |
342 | blksz = E.__class__.blksz | |
343 | if VERBOSE: dump_ocb(E) | |
344 | Lgamma, Lxinv = ocb_masks(E) | |
345 | if tsz is None: tsz = blksz | |
346 | a = Z(blksz) | |
347 | o = E.encrypt(n ^ Lgamma[0]) | |
348 | if VERBOSE: print 'R = %s' % hex(o) | |
349 | i = 1 | |
350 | y = C.WriteBuffer() | |
351 | v, tl = blocks(m, blksz) | |
352 | for x in v: | |
353 | b = ntz(i) | |
354 | o ^= Lgamma[b] | |
355 | a ^= x | |
356 | if VERBOSE: | |
357 | print 'Z[%d]: %d -> %s' % (i - 1, b, hex(o)) | |
358 | print 'A[%d]: %s' % (i - 1, hex(a)) | |
359 | y.put(E.encrypt(x ^ o) ^ o) | |
360 | i += 1 | |
361 | b = ntz(i) | |
362 | o ^= Lgamma[b] | |
363 | n = len(tl) | |
364 | if VERBOSE: | |
365 | print 'Z[%d]: %d -> %s' % (i - 1, b, hex(o)) | |
366 | print 'LEN = %s' % hex(C.MP(8*n).storeb(blksz)) | |
367 | yfinal = E.encrypt(C.MP(8*n).storeb(blksz) ^ Lxinv ^ o) | |
368 | cfinal = tl ^ yfinal[:n] | |
369 | a ^= o ^ (tl + yfinal[n:]) | |
370 | y.put(cfinal) | |
371 | t = E.encrypt(a) | |
372 | if h: t ^= pmac1(E, h) | |
373 | return C.ByteString(y), C.ByteString(t[:tsz]) | |
374 | ||
375 | def ocb2(E, n, h, m, tsz = None): | |
376 | blksz = E.__class__.blksz | |
377 | if tsz is None: tsz = blksz | |
378 | p = prim(8*blksz) | |
379 | L = E.encrypt(n) | |
380 | o = mul_blk_gf(L, 2, p) | |
381 | a = Z(blksz) | |
382 | v, tl = blocks(m, blksz) | |
383 | y = C.WriteBuffer() | |
384 | for x in v: | |
385 | a ^= x | |
386 | y.put(E.encrypt(x ^ o) ^ o) | |
387 | o = mul_blk_gf(o, 2, p) | |
388 | n = len(tl) | |
389 | yfinal = E.encrypt(C.MP(8*n).storeb(blksz) ^ o) | |
390 | cfinal = tl ^ yfinal[:n] | |
391 | a ^= (tl + yfinal[n:]) ^ mul_blk_gf(o, 3, p) | |
392 | y.put(cfinal) | |
393 | t = E.encrypt(a) | |
394 | if h: t ^= pmac2(E, h) | |
395 | return C.ByteString(y), C.ByteString(t[:tsz]) | |
396 | ||
397 | OCB3_STRETCH = { 8: (5, 25), | |
398 | 12: (6, 33), | |
399 | 16: (6, 8), | |
400 | 24: (7, 40), | |
86082bbc MW |
401 | 32: (7, 120), |
402 | 64: (8, 240) } | |
54482987 MW |
403 | |
404 | def ocb3(E, n, h, m, tsz = None): | |
405 | blksz = E.__class__.blksz | |
406 | if tsz is None: tsz = blksz | |
407 | Lstar, Ldollar, Lgamma = ocb3_masks(E) | |
408 | if VERBOSE: dump_ocb3(E) | |
409 | ||
410 | ## Figure out how much we need to glue onto the nonce. This ends up being | |
411 | ## [t mod w]_v || 0^p || 1 || N, where w is the block size in bits, t is | |
412 | ## the tag length in bits, v = floor(log_2(w - 1)) + 1, and p = w - l(N) - | |
413 | ## v - 1. But this is an annoying way to think about it because of the | |
414 | ## byte misalignment. Instead, think of it as a byte-aligned prefix | |
415 | ## encoding the tag and an `is the nonce full-length' flag, followed by | |
416 | ## optional padding, and then the nonce: | |
417 | ## | |
418 | ## F || N if l(N) = w - f | |
419 | ## F || 0^p || 1 || N otherwise | |
420 | ## | |
421 | ## where F is [t mod w]_v || 0^{f-v-1} || b; f = floor(log_2(w - 1)) + 2; | |
422 | ## b is 1 if l(N) = w - f, or 0 otherwise; and p = w - f - l(N) - 1. | |
423 | tszbits = C.MP(8*blksz - 1).nbits | |
424 | fwd = tszbits/8 + 1 | |
425 | f = tsz << 3 + 8*fwd - tszbits | |
426 | ||
427 | ## Form the augmented nonce. | |
428 | nb = C.WriteBuffer() | |
429 | nsz, nwd = len(n), blksz - fwd | |
430 | if nsz == nwd: f |= 1 | |
431 | nb.put(C.MP(f).storeb(fwd)) | |
432 | if nsz < nwd: nb.zero(nwd - nsz - 1).putu8(1) | |
433 | nb.put(n) | |
434 | nn = C.ByteString(nb) | |
435 | if VERBOSE: print 'N\' : %s' % hex(nn) | |
436 | ||
437 | ## Calculate the initial offset. | |
438 | split, shift = OCB3_STRETCH[blksz] | |
439 | splitbits = 1 << split | |
440 | t2ps = C.MP(0).setbit(splitbits) | |
441 | lomask = (C.MP(0).setbit(split) - 1) | |
442 | himask = ~lomask | |
443 | top, bottom = nn&himask.storeb2c(blksz), C.MP.loadb(nn)&lomask | |
444 | ktop = C.MP.loadb(E.encrypt(top)) | |
445 | stretch = (ktop << splitbits) | \ | |
446 | (((ktop ^ (ktop << shift)) >> (8*blksz - splitbits))%t2ps) | |
447 | o = (stretch >> splitbits - bottom).storeb(blksz) | |
448 | a = C.ByteString.zero(blksz) | |
449 | if VERBOSE: | |
450 | print 'bottom : %d' % bottom | |
451 | print 'Ktop : %s' % hex(ktop.storeb(blksz)) | |
452 | print 'Stretch : %s' % hex(stretch.storeb(blksz + (1 << split - 3))) | |
453 | print 'Offset_0 : %s' % hex(o) | |
454 | ||
455 | ## Split the message into blocks. | |
456 | i = 1 | |
457 | y = C.WriteBuffer() | |
458 | v, tl = blocks0(m, blksz) | |
459 | for x in v: | |
460 | b = ntz(i) | |
461 | o ^= Lgamma[b] | |
462 | a ^= x | |
463 | if VERBOSE: | |
464 | print 'Offset_%-3d: %s' % (i, hex(o)) | |
465 | print 'Checksum_%d: %s' % (i, hex(a)) | |
466 | y.put(E.encrypt(x ^ o) ^ o) | |
467 | i += 1 | |
468 | if tl: | |
469 | o ^= Lstar | |
470 | n = len(tl) | |
471 | pad = E.encrypt(o) | |
472 | a ^= pad10star(tl, blksz) | |
473 | if VERBOSE: | |
474 | print 'Offset_* : %s' % hex(o) | |
475 | print 'Checksum_*: %s' % hex(a) | |
476 | y.put(tl ^ pad[0:n]) | |
477 | o ^= Ldollar | |
478 | t = E.encrypt(a ^ o) ^ pmac3(E, h) | |
479 | return C.ByteString(y), C.ByteString(t[:tsz]) | |
480 | ||
481 | def ocbgen(bc): | |
482 | w = bc.blksz | |
483 | return [(w, 0, 0), (w, 1, 0), (w, 0, 1), | |
484 | (w, 0, 3*w), | |
485 | (w, 3*w, 3*w), | |
486 | (w, 0, 3*w + 5), | |
487 | (w, 3*w - 5, 3*w + 5)] | |
488 | ||
489 | def ocb3gen(bc): | |
490 | w = bc.blksz | |
491 | return [(w - 2, 0, 0), (w - 2, 1, 0), (w - 2, 0, 1), | |
492 | (w - 5, 0, 3*w), | |
493 | (w - 3, 3*w, 3*w), | |
494 | (w - 2, 0, 3*w + 5), | |
495 | (w - 2, 3*w - 5, 3*w + 5)] | |
496 | ||
497 | ###-------------------------------------------------------------------------- | |
498 | ### Main program. | |
499 | ||
500 | VERBOSE = LRVERBOSE = False | |
501 | ||
502 | class struct (object): | |
503 | def __init__(me, **kw): | |
504 | me.__dict__.update(kw) | |
505 | ||
506 | def mct(ocb, bc, ksz, nsz, tsz): | |
507 | k = C.MP(8*tsz).storeb(ksz) | |
508 | E = bc(k) | |
509 | e = C.ByteString('') | |
510 | n = C.MP(1) | |
511 | cbuf = C.WriteBuffer() | |
512 | for i in xrange(128): | |
513 | s = C.ByteString.zero(i) | |
514 | y, t = ocb(E, n.storeb(nsz), s, s, tsz); n += 1; cbuf.put(y).put(t) | |
515 | y, t = ocb(E, n.storeb(nsz), e, s, tsz); n += 1; cbuf.put(y).put(t) | |
516 | y, t = ocb(E, n.storeb(nsz), s, e, tsz); n += 1; cbuf.put(y).put(t) | |
517 | _, t = ocb(E, n.storeb(nsz), C.ByteString(cbuf), e, tsz) | |
518 | print hex(t) | |
519 | ||
520 | argc = len(argv) | |
521 | argi = 1 | |
522 | ||
523 | def usage(): | |
524 | print >>stderr, """\ | |
525 | usage: %s [-v] OCB BLKC OP ARGS... | |
526 | mct KSZ NSZ TSZ | |
527 | kat K N0 TSZ HSZ,MSZ ... | |
528 | lraes W K M""" % argv[0] | |
529 | exit(2) | |
530 | ||
531 | def arg(must = True, default = None): | |
532 | global argi | |
533 | if argi < argc: argi += 1; return argv[argi - 1] | |
534 | elif not must: return default | |
535 | else: usage() | |
536 | ||
537 | MODEMAP = { 'ocb1': ocb1, | |
538 | 'ocb2': ocb2, | |
539 | 'ocb3': ocb3 } | |
540 | ||
541 | def pat(sz): | |
542 | b = C.WriteBuffer() | |
543 | for i in xrange(sz): b.putu8(i%256) | |
544 | return C.ByteString(b) | |
545 | ||
546 | opt = arg() | |
547 | if opt == '-v': VERBOSE = True; opt = arg() | |
548 | ocb = MODEMAP[opt] | |
549 | ||
550 | bcname = arg() | |
551 | bc = None | |
552 | for d in LRAES, C.gcprps: | |
553 | try: bc = d[bcname] | |
554 | except KeyError: pass | |
555 | else: break | |
556 | if bc is None: raise KeyError, bcname | |
557 | ||
558 | mode = arg() | |
559 | if mode == 'mct': | |
560 | ksz = int(arg()); nsz = int(arg()); tsz = int(arg()) | |
561 | mct(ocb, bc, ksz, nsz, tsz) | |
562 | exit(0) | |
563 | ||
564 | elif mode == 'kat': | |
565 | k = C.bytes(arg()) | |
566 | E = bc(k) | |
567 | nspec = arg() | |
568 | if nspec.endswith('+'): ninc = 1; nspec = nspec[:-1] | |
569 | else: ninc = 0 | |
570 | n0 = C.bytes(nspec) | |
571 | nz = C.MP.loadb(n0) | |
572 | nsz = len(n0) | |
573 | tsz = int(arg()) | |
574 | ||
575 | print 'K: %s' % hex(k) | |
576 | ||
577 | while True: | |
578 | hmsz = arg(must = False) | |
579 | if hmsz is None: break | |
580 | hsz, msz = map(int, hmsz.split(',')) | |
581 | n = nz.storeb(nsz) | |
582 | h = pat(hsz) | |
583 | m = pat(msz) | |
584 | y, t = ocb(E, n, h, m, tsz) | |
585 | ||
586 | print 'N: %s' % hex(n) | |
587 | print 'A: %s' % hex(h) | |
588 | print 'P: %s' % hex(m) | |
589 | print 'C: %s%s' % (hex(y), hex(t)) | |
590 | nz += ninc | |
591 | ||
592 | elif mode == 'lraes': | |
593 | w = int(arg()) | |
594 | k = C.bytes(arg()) | |
595 | m = C.bytes(arg()) | |
596 | LRVERBOSE = True | |
597 | lr = LubyRackoffCipher(bc, w) | |
598 | E = lr(k) | |
599 | ||
600 | c = E.encrypt(m) | |
601 | print 'E\'(K, m) = %s' % hex(c) | |
602 | ||
603 | else: | |
604 | usage() | |
605 | ||
606 | ###----- That's all, folks -------------------------------------------------- |