mdw@git.distorted.org.uk Git - catacomb/blob - utils/advmodes

   1 #! /usr/bin/python
   2
   3 from sys import argv
   4 from struct import pack
   5 from itertools import izip
   6 import catacomb as C
   7
   8 R = C.FibRand(0)
   9
  10 ###--------------------------------------------------------------------------
  11 ### Utilities.
  12
  13 def combs(things, k):
  14   ii = range(k)
  15   n = len(things)
  16   while True:
  17     yield [things[i] for i in ii]
  18     for j in xrange(k):
  19       if j == k - 1: lim = n
  20       else: lim = ii[j + 1]
  21       i = ii[j] + 1
  22       if i < lim:
  23         ii[j] = i
  24         break
  25       ii[j] = j
  26     else:
  27       return
  28
  29 POLYMAP = {}
  30
  31 def poly(nbits):
  32   try: return POLYMAP[nbits]
  33   except KeyError: pass
  34   base = C.GF(0).setbit(nbits).setbit(0)
  35   for k in xrange(1, nbits, 2):
  36     for cc in combs(range(1, nbits), k):
  37       p = base + sum(C.GF(0).setbit(c) for c in cc)
  38       if p.irreduciblep(): POLYMAP[nbits] = p; return p
  39   raise ValueError, nbits
  40
  41 def Z(n):
  42   return C.ByteString.zero(n)
  43
  44 def mul_blk_gf(m, x, p): return ((C.GF.loadb(m)*x)%p).storeb((p.nbits + 6)/8)
  45
  46 def with_lastp(it):
  47   it = iter(it)
  48   try: j = next(it)
  49   except StopIteration: raise ValueError, 'empty iter'
  50   lastp = False
  51   while not lastp:
  52     i = j
  53     try: j = next(it)
  54     except StopIteration: lastp = True
  55     yield i, lastp
  56
  57 def safehex(x):
  58   if len(x): return hex(x)
  59   else: return '""'
  60
  61 def keylens(ksz):
  62   sel = []
  63   if isinstance(ksz, C.KeySZSet): kk = ksz.set
  64   elif isinstance(ksz, C.KeySZRange): kk = range(ksz.min, ksz.max, ksz.mod)
  65   elif isinstance(ksz, C.KeySZAny): kk = range(64); sel = [0]
  66   kk = list(kk); kk = kk[:]
  67   n = len(kk)
  68   while n and len(sel) < 4:
  69     i = R.range(n)
  70     n -= 1
  71     kk[i], kk[n] = kk[n], kk[i]
  72     sel.append(kk[n])
  73   return sel
  74
  75 def pad0star(m, w):
  76   n = len(m)
  77   if not n: r = w
  78   else: r = (-len(m))%w
  79   if r: m += Z(r)
  80   return C.ByteString(m)
  81
  82 def pad10star(m, w):
  83   r = w - len(m)%w
  84   if r: m += '\x80' + Z(r - 1)
  85   return C.ByteString(m)
  86
  87 def ntz(i):
  88   j = 0
  89   while (i&1) == 0: i >>= 1; j += 1
  90   return j
  91
  92 def blocks(x, w):
  93   v, i, n = [], 0, len(x)
  94   while n - i > w:
  95     v.append(C.ByteString(x[i:i + w]))
  96     i += w
  97   return v, C.ByteString(x[i:])
  98
  99 EMPTY = C.bytes('')
 100
 101 def blocks0(x, w):
 102   v, tl = blocks(x, w)
 103   if len(tl) == w: v.append(tl); tl = EMPTY
 104   return v, tl
 105
 106 def dummygen(bc): return []
 107
 108 CUSTOM = {}
 109
 110 ###--------------------------------------------------------------------------
 111 ### RC6.
 112
 113 class RC6Cipher (type):
 114   def __new__(cls, w, r):
 115     name = 'rc6-%d/%d' % (w, r)
 116     me = type(name, (RC6Base,), {})
 117     me.name = name
 118     me.r = r
 119     me.w = w
 120     me.blksz = w/2
 121     me.keysz = C.KeySZRange(me.blksz, 1, 255, 1)
 122     return me
 123
 124 def rotw(w):
 125   return w.bit_length() - 1
 126
 127 def rol(w, x, n):
 128   m0, m1 = C.MP(0).setbit(w - n) - 1, C.MP(0).setbit(n) - 1
 129   return ((x&m0) << n) | (x >> (w - n))&m1
 130
 131 def ror(w, x, n):
 132   m0, m1 = C.MP(0).setbit(n) - 1, C.MP(0).setbit(w - n) - 1
 133   return ((x&m0) << (w - n)) | (x >> n)&m1
 134
 135 class RC6Base (object):
 136
 137   ## Magic constants.
 138   P400 = C.MP(0xb7e151628aed2a6abf7158809cf4f3c762e7160f38b4da56a784d9045190cfef324e7738926cfbe5f4bf8d8d8c31d763da06)
 139   Q400 = C.MP(0x9e3779b97f4a7c15f39cc0605cedc8341082276bf3a27251f86c6a11d0c18e952767f0b153d27b7f0347045b5bf1827f0188)
 140
 141   def __init__(me, k):
 142
 143     ## Build the magic numbers.
 144     P = me.P400 >> (400 - me.w)
 145     if P%2 == 0: P += 1
 146     Q = me.Q400 >> (400 - me.w)
 147     if Q%2 == 0: Q += 1
 148     M = C.MP(0).setbit(me.w) - 1
 149
 150     ## Convert the key into words.
 151     wb = me.w/8
 152     c = (len(k) + wb - 1)/wb
 153     kb, ktl = blocks(k, me.w/8)
 154     L = map(C.MP.loadl, kb + [ktl])
 155     assert c == len(L)
 156
 157     ## Build the subkey table.
 158     me.d = rotw(me.w)
 159     n = 2*me.r + 4
 160     S = [(P + i*Q)&M for i in xrange(n)]
 161
 162     ##for j in xrange(c):
 163     ##  print 'L[%3d] = %s' % (j, hex(L[j]).upper()[2:].rjust(2*wb, '0'))
 164     ##for i in xrange(n):
 165     ##  print 'S[%3d] = %s' % (i, hex(S[i]).upper()[2:].rjust(2*wb, '0'))
 166
 167     i = j = 0
 168     A = B = C.MP(0)
 169
 170     for s in xrange(3*max(c, n)):
 171       A = S[i] = rol(me.w, S[i] + A + B, 3)
 172       B = L[j] = rol(me.w, L[j] + A + B, (A + B)%(1 << me.d))
 173       ##print 'S[%3d] = %s' % (i, hex(S[i]).upper()[2:].rjust(2*wb, '0'))
 174       ##print 'L[%3d] = %s' % (j, hex(L[j]).upper()[2:].rjust(2*wb, '0'))
 175       i = (i + 1)%n
 176       j = (j + 1)%c
 177
 178     ## Done.
 179     me.s = S
 180
 181   def encrypt(me, x):
 182     M = C.MP(0).setbit(me.w) - 1
 183     a, b, c, d = map(C.MP.loadl, blocks0(x, me.blksz/4)[0])
 184     b = (b + me.s[0])&M
 185     d = (d + me.s[1])&M
 186     ##print 'B = %s' % (hex(b).upper()[2:].rjust(me.w/4, '0'))
 187     ##print 'D = %s' % (hex(d).upper()[2:].rjust(me.w/4, '0'))
 188     for i in xrange(2, 2*me.r + 2, 2):
 189       t = rol(me.w, 2*b*b + b, me.d)
 190       u = rol(me.w, 2*d*d + d, me.d)
 191       a = (rol(me.w, a ^ t, u%(1 << me.d)) + me.s[i + 0])&M
 192       c = (rol(me.w, c ^ u, t%(1 << me.d)) + me.s[i + 1])&M
 193       ##print 'A = %s' % (hex(a).upper()[2:].rjust(me.w/4, '0'))
 194       ##print 'C = %s' % (hex(c).upper()[2:].rjust(me.w/4, '0'))
 195       a, b, c, d = b, c, d, a
 196     a = (a + me.s[2*me.r + 2])&M
 197     c = (c + me.s[2*me.r + 3])&M
 198     ##print 'A = %s' % (hex(a).upper()[2:].rjust(me.w/4, '0'))
 199     ##print 'C = %s' % (hex(c).upper()[2:].rjust(me.w/4, '0'))
 200     return C.ByteString(a.storel(me.blksz/4) + b.storel(me.blksz/4) +
 201                         c.storel(me.blksz/4) + d.storel(me.blksz/4))
 202
 203   def decrypt(me, x):
 204     M = C.MP(0).setbit(me.w) - 1
 205     a, b, c, d = map(C.MP.loadl, blocks0(x, me.blksz/4))
 206     c = (c - me.s[2*me.r + 3])&M
 207     a = (a - me.s[2*me.r + 2])&M
 208     for i in xrange(2*me.r + 1, 1, -2):
 209       a, b, c, d = d, a, b, c
 210       u = rol(me.w, 2*d*d + d, me.d)
 211       t = rol(me.w, 2*b*b + b, me.d)
 212       c = ror(me.w, (c - me.s[i + 1])&M, t%(1 << me.d)) ^ u
 213       a = ror(me.w, (a - me.s[i + 0])&M, u%(1 << me.d)) ^ t
 214     a = (a + s[2*me.r + 2])&M
 215     c = (c + s[2*me.r + 3])&M
 216     return C.ByteString(a.storel(me.blksz/4) + b.storel(me.blksz/4) +
 217                         c.storel(me.blksz/4) + d.storel(me.blksz/4))
 218
 219 for (w, r) in [(8, 16), (16, 16), (24, 16), (32, 16),
 220                (32, 20), (48, 16), (64, 16), (96, 16), (128, 16),
 221                (192, 16), (256, 16), (400, 16)]:
 222   CUSTOM['rc6-%d/%d' % (w, r)] = RC6Cipher(w, r)
 223
 224 ###--------------------------------------------------------------------------
 225 ### OMAC (or CMAC).
 226
 227 def omac_masks(E):
 228   blksz = E.__class__.blksz
 229   p = poly(8*blksz)
 230   z = Z(blksz)
 231   L = E.encrypt(z)
 232   m0 = mul_blk_gf(L, 2, p)
 233   m1 = mul_blk_gf(m0, 2, p)
 234   return m0, m1
 235
 236 def dump_omac(E):
 237   blksz = E.__class__.blksz
 238   m0, m1 = omac_masks(E)
 239   print 'L = %s' % hex(E.encrypt(Z(blksz)))
 240   print 'm0 = %s' % hex(m0)
 241   print 'm1 = %s' % hex(m1)
 242   for t in xrange(3):
 243     print 'v%d = %s' % (t, hex(E.encrypt(C.MP(t).storeb(blksz))))
 244     print 'z%d = %s' % (t, hex(omac(E, t, '')))
 245
 246 def omac(E, t, m):
 247   blksz = E.__class__.blksz
 248   m0, m1 = omac_masks(E)
 249   a = Z(blksz)
 250   if t is not None: m = C.MP(t).storeb(blksz) + m
 251   v, tl = blocks(m, blksz)
 252   for x in v: a = E.encrypt(a ^ x)
 253   r = blksz - len(tl)
 254   if r == 0:
 255     a = E.encrypt(a ^ tl ^ m0)
 256   else:
 257     pad = pad10star(tl, blksz)
 258     a = E.encrypt(a ^ pad ^ m1)
 259   return a
 260
 261 def cmac(E, m):
 262   if VERBOSE: dump_omac(E)
 263   return omac(E, None, m),
 264
 265 def cmacgen(bc):
 266   return [(0,), (1,),
 267           (3*bc.blksz,),
 268           (3*bc.blksz - 5,)]
 269
 270 ###--------------------------------------------------------------------------
 271 ### Counter mode.
 272
 273 def ctr(E, m, c0):
 274   blksz = E.__class__.blksz
 275   y = C.WriteBuffer()
 276   c = C.MP.loadb(c0)
 277   while y.size < len(m):
 278     y.put(E.encrypt(c.storeb(blksz)))
 279     c += 1
 280   return C.ByteString(m) ^ C.ByteString(y)[:len(m)]
 281
 282 ###--------------------------------------------------------------------------
 283 ### EAX.
 284
 285 def eaxenc(E, n, h, m, tsz = None):
 286   if VERBOSE:
 287     print 'k = %s' % hex(k)
 288     print 'n = %s' % hex(n)
 289     print 'h = %s' % hex(h)
 290     print 'm = %s' % hex(m)
 291     dump_omac(E)
 292   if tsz is None: tsz = E.__class__.blksz
 293   c0 = omac(E, 0, n)
 294   y = ctr(E, m, c0)
 295   ht = omac(E, 1, h)
 296   yt = omac(E, 2, y)
 297   if VERBOSE:
 298     print 'c0 = %s' % hex(c0)
 299     print 'ht = %s' % hex(ht)
 300     print 'yt = %s' % hex(yt)
 301   return y, C.ByteString((c0 ^ ht ^ yt)[:tsz])
 302
 303 def eaxdec(E, n, h, y, t):
 304   if VERBOSE:
 305     print 'k = %s' % hex(k)
 306     print 'n = %s' % hex(n)
 307     print 'h = %s' % hex(h)
 308     print 'y = %s' % hex(y)
 309     print 't = %s' % hex(t)
 310     dump_omac(E)
 311   c0 = omac(E, 0, n)
 312   m = ctr(E, y, c0)
 313   ht = omac(E, 1, h)
 314   yt = omac(E, 2, y)
 315   if VERBOSE:
 316     print 'c0 = %s' % hex(c0)
 317     print 'ht = %s' % hex(ht)
 318     print 'yt = %s' % hex(yt)
 319   if t == (c0 ^ ht ^ yt)[:len(t)]: return m,
 320   else: return None,
 321
 322 def eaxgen(bc):
 323   return [(0, 0, 0), (1, 0, 0), (0, 1, 0), (0, 0, 1),
 324           (bc.blksz, 3*bc.blksz, 3*bc.blksz),
 325           (bc.blksz - 1, 3*bc.blksz - 5, 3*bc.blksz + 5)]
 326
 327 ###--------------------------------------------------------------------------
 328 ### Main program.
 329
 330 class struct (object):
 331   def __init__(me, **kw):
 332     me.__dict__.update(kw)
 333
 334 binarg = struct(mk = R.block, parse = C.bytes, show = safehex)
 335 intarg = struct(mk = lambda x: x, parse = int, show = None)
 336
 337 MODEMAP = { 'eax-enc': (eaxgen, 3*[binarg] + [intarg], eaxenc),
 338             'eax-dec': (dummygen, 4*[binarg], eaxdec),
 339             'cmac': (cmacgen, [binarg], cmac) }
 340
 341 mode = argv[1]
 342 bc = None
 343 for d in CUSTOM, C.gcprps:
 344   try: bc = d[argv[2]]
 345   except KeyError: pass
 346   else: break
 347 if bc is None: raise KeyError, argv[2]
 348 if len(argv) == 3:
 349   VERBOSE = False
 350   gen, argty, func = MODEMAP[mode]
 351   if mode.endswith('-enc'): mode = mode[:-4]
 352   print '%s-%s {' % (bc.name, mode)
 353   for ksz in keylens(bc.keysz):
 354     for argvals in gen(bc):
 355       k = R.block(ksz)
 356       args = [t.mk(a) for t, a in izip(argty, argvals)]
 357       rets = func(bc(k), *args)
 358       print '  %s' % safehex(k)
 359       for t, a in izip(argty, args):
 360         if t.show: print '    %s' % t.show(a)
 361       for r, lastp in with_lastp(rets):
 362         print '    %s%s' % (safehex(r), lastp and ';' or '')
 363   print '}'
 364 else:
 365   VERBOSE = True
 366   k = C.bytes(argv[3])
 367   gen, argty, func = MODEMAP[mode]
 368   args = [t.parse(a) for t, a in izip(argty, argv[4:])]
 369   rets = func(bc(k), *args)
 370   for r in rets:
 371     if r is None: print "X"
 372     else: print hex(r)
 373
 374 ###----- That's all, folks --------------------------------------------------