mdw@git.distorted.org.uk Git - catacomb-python/blob - catacomb/__init__.py

   1 ### -*-python-*-
   2 ###
   3 ### Setup for Catacomb/Python bindings
   4 ###
   5 ### (c) 2004 Straylight/Edgeware
   6 ###
   7
   8 ###----- Licensing notice ---------------------------------------------------
   9 ###
  10 ### This file is part of the Python interface to Catacomb.
  11 ###
  12 ### Catacomb/Python is free software; you can redistribute it and/or modify
  13 ### it under the terms of the GNU General Public License as published by
  14 ### the Free Software Foundation; either version 2 of the License, or
  15 ### (at your option) any later version.
  16 ###
  17 ### Catacomb/Python is distributed in the hope that it will be useful,
  18 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ### GNU General Public License for more details.
  21 ###
  22 ### You should have received a copy of the GNU General Public License
  23 ### along with Catacomb/Python; if not, write to the Free Software Foundation,
  24 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25
  26 import _base
  27 import types as _types
  28 from binascii import hexlify as _hexify, unhexlify as _unhexify
  29 from sys import argv as _argv
  30
  31 ###--------------------------------------------------------------------------
  32 ### Basic stuff.
  33
  34 ## For the benefit of the default keyreporter, we need the program na,e.
  35 _base._ego(_argv[0])
  36
  37 ## Initialize the module.  Drag in the static methods of the various
  38 ## classes; create names for the various known crypto algorithms.
  39 def _init():
  40   d = globals()
  41   b = _base.__dict__;
  42   for i in b:
  43     if i[0] != '_':
  44       d[i] = b[i];
  45   for i in ['MP', 'GF', 'Field',
  46             'ECPt', 'ECPtCurve', 'ECCurve', 'ECInfo',
  47             'DHInfo', 'BinDHInfo', 'RSAPriv', 'BBSPriv',
  48             'PrimeFilter', 'RabinMiller',
  49             'Group', 'GE',
  50             'KeySZ', 'KeyData']:
  51     c = d[i]
  52     pre = '_' + i + '_'
  53     plen = len(pre)
  54     for j in b:
  55       if j[:plen] == pre:
  56         setattr(c, j[plen:], classmethod(b[j]))
  57   for i in [gcciphers, gchashes, gcmacs, gcprps]:
  58     for c in i.itervalues():
  59       d[c.name.replace('-', '_').translate(None, '/')] = c
  60   for c in gccrands.itervalues():
  61     d[c.name.replace('-', '_').translate(None, '/') + 'rand'] = c
  62 _init()
  63
  64 ## A handy function for our work: add the methods of a named class to an
  65 ## existing class.  This is how we write the Python-implemented parts of our
  66 ## mostly-C types.
  67 def _augment(c, cc):
  68   for i in cc.__dict__:
  69     a = cc.__dict__[i]
  70     if type(a) is _types.MethodType:
  71       a = a.im_func
  72     elif type(a) not in (_types.FunctionType, staticmethod, classmethod):
  73       continue
  74     setattr(c, i, a)
  75
  76 ## Parsing functions tend to return the object parsed and the remainder of
  77 ## the input.  This checks that the remainder is input and, if so, returns
  78 ## just the object.
  79 def _checkend(r):
  80   x, rest = r
  81   if rest != '':
  82     raise SyntaxError, 'junk at end of string'
  83   return x
  84
  85 ###--------------------------------------------------------------------------
  86 ### Bytestrings.
  87
  88 class _tmp:
  89   def fromhex(x):
  90     return ByteString(_unhexify(x))
  91   fromhex = staticmethod(fromhex)
  92   def __hex__(me):
  93     return _hexify(me)
  94   def __repr__(me):
  95     return 'bytes(%r)' % hex(me)
  96 _augment(ByteString, _tmp)
  97 ByteString.__hash__ = str.__hash__
  98 bytes = ByteString.fromhex
  99
 100 ###--------------------------------------------------------------------------
 101 ### Hashing.
 102
 103 class _tmp:
 104   def check(me, h):
 105     hh = me.done()
 106     return ctstreq(h, hh)
 107 _augment(GHash, _tmp)
 108 _augment(Poly1305Hash, _tmp)
 109
 110 ###--------------------------------------------------------------------------
 111 ### NaCl `secretbox'.
 112
 113 def secret_box(k, n, m):
 114   E = xsalsa20(k).setiv(n)
 115   r = E.enczero(poly1305.keysz.default)
 116   s = E.enczero(poly1305.masksz)
 117   y = E.encrypt(m)
 118   t = poly1305(r)(s).hash(y).done()
 119   return ByteString(t + y)
 120
 121 def secret_unbox(k, n, c):
 122   E = xsalsa20(k).setiv(n)
 123   r = E.enczero(poly1305.keysz.default)
 124   s = E.enczero(poly1305.masksz)
 125   y = c[poly1305.tagsz:]
 126   if not poly1305(r)(s).hash(y).check(c[0:poly1305.tagsz]):
 127     raise ValueError, 'decryption failed'
 128   return E.decrypt(c[poly1305.tagsz:])
 129
 130 ###--------------------------------------------------------------------------
 131 ### Multiprecision integers and binary polynomials.
 132
 133 def _split_rat(x):
 134   if isinstance(x, BaseRat): return x._n, x._d
 135   else: return x, 1
 136 class BaseRat (object):
 137   """Base class implementing fields of fractions over Euclidean domains."""
 138   def __new__(cls, a, b):
 139     a, b = cls.RING(a), cls.RING(b)
 140     q, r = divmod(a, b)
 141     if r == 0: return q
 142     g = b.gcd(r)
 143     me = super(BaseRat, cls).__new__(cls)
 144     me._n = a//g
 145     me._d = b//g
 146     return me
 147   @property
 148   def numer(me): return me._n
 149   @property
 150   def denom(me): return me._d
 151   def __str__(me): return '%s/%s' % (me._n, me._d)
 152   def __repr__(me): return '%s(%s, %s)' % (type(me).__name__, me._n, me._d)
 153
 154   def __add__(me, you):
 155     n, d = _split_rat(you)
 156     return type(me)(me._n*d + n*me._d, d*me._d)
 157   __radd__ = __add__
 158   def __sub__(me, you):
 159     n, d = _split_rat(you)
 160     return type(me)(me._n*d - n*me._d, d*me._d)
 161   def __rsub__(me, you):
 162     n, d = _split_rat(you)
 163     return type(me)(n*me._d - me._n*d, d*me._d)
 164   def __mul__(me, you):
 165     n, d = _split_rat(you)
 166     return type(me)(me._n*n, me._d*d)
 167   def __div__(me, you):
 168     n, d = _split_rat(you)
 169     return type(me)(me._n*d, me._d*n)
 170   def __rdiv__(me, you):
 171     n, d = _split_rat(you)
 172     return type(me)(me._d*n, me._n*d)
 173   def __cmp__(me, you):
 174     n, d = _split_rat(you)
 175     return type(me)(me._n*d, n*me._d)
 176   def __rcmp__(me, you):
 177     n, d = _split_rat(you)
 178     return cmp(n*me._d, me._n*d)
 179
 180 class IntRat (BaseRat):
 181   RING = MP
 182
 183 class GFRat (BaseRat):
 184   RING = GF
 185
 186 class _tmp:
 187   def negp(x): return x < 0
 188   def posp(x): return x > 0
 189   def zerop(x): return x == 0
 190   def oddp(x): return x.testbit(0)
 191   def evenp(x): return not x.testbit(0)
 192   def mont(x): return MPMont(x)
 193   def barrett(x): return MPBarrett(x)
 194   def reduce(x): return MPReduce(x)
 195   def __div__(me, you): return IntRat(me, you)
 196   def __rdiv__(me, you): return IntRat(you, me)
 197 _augment(MP, _tmp)
 198
 199 class _tmp:
 200   def zerop(x): return x == 0
 201   def reduce(x): return GFReduce(x)
 202   def trace(x, y): return x.reduce().trace(y)
 203   def halftrace(x, y): return x.reduce().halftrace(y)
 204   def modsqrt(x, y): return x.reduce().sqrt(y)
 205   def quadsolve(x, y): return x.reduce().quadsolve(y)
 206   def __div__(me, you): return GFRat(me, you)
 207   def __rdiv__(me, you): return GFRat(you, me)
 208 _augment(GF, _tmp)
 209
 210 class _tmp:
 211   def product(*arg):
 212     'product(ITERABLE) or product(I, ...) -> PRODUCT'
 213     return MPMul(*arg).done()
 214   product = staticmethod(product)
 215 _augment(MPMul, _tmp)
 216
 217 ###--------------------------------------------------------------------------
 218 ### Abstract fields.
 219
 220 class _tmp:
 221   def fromstring(str): return _checkend(Field.parse(str))
 222   fromstring = staticmethod(fromstring)
 223 _augment(Field, _tmp)
 224
 225 class _tmp:
 226   def __repr__(me): return '%s(%sL)' % (type(me).__name__, me.p)
 227   def __hash__(me): return 0x114401de ^ hash(me.p)
 228   def ec(me, a, b): return ECPrimeProjCurve(me, a, b)
 229 _augment(PrimeField, _tmp)
 230
 231 class _tmp:
 232   def __repr__(me): return '%s(%sL)' % (type(me).__name__, hex(me.p))
 233   def ec(me, a, b): return ECBinProjCurve(me, a, b)
 234 _augment(BinField, _tmp)
 235
 236 class _tmp:
 237   def __hash__(me): return 0x23e4701c ^ hash(me.p)
 238 _augment(BinPolyField, _tmp)
 239
 240 class _tmp:
 241   def __hash__(me):
 242     h = 0x9a7d6240
 243     h ^=   hash(me.p)
 244     h ^= 2*hash(me.beta) & 0xffffffff
 245     return h
 246 _augment(BinNormField, _tmp)
 247
 248 class _tmp:
 249   def __str__(me): return str(me.value)
 250   def __repr__(me): return '%s(%s)' % (repr(me.field), repr(me.value))
 251 _augment(FE, _tmp)
 252
 253 ###--------------------------------------------------------------------------
 254 ### Elliptic curves.
 255
 256 class _tmp:
 257   def __repr__(me):
 258     return '%s(%r, %s, %s)' % (type(me).__name__, me.field, me.a, me.b)
 259   def frombuf(me, s):
 260     return ecpt.frombuf(me, s)
 261   def fromraw(me, s):
 262     return ecpt.fromraw(me, s)
 263   def pt(me, *args):
 264     return me(*args)
 265 _augment(ECCurve, _tmp)
 266
 267 class _tmp:
 268   def __hash__(me):
 269     h = 0x6751d341
 270     h ^=   hash(me.field)
 271     h ^= 2*hash(me.a) ^ 0xffffffff
 272     h ^= 5*hash(me.b) ^ 0xffffffff
 273     return h
 274 _augment(ECPrimeCurve, _tmp)
 275
 276 class _tmp:
 277   def __hash__(me):
 278     h = 0x2ac203c5
 279     h ^=   hash(me.field)
 280     h ^= 2*hash(me.a) ^ 0xffffffff
 281     h ^= 5*hash(me.b) ^ 0xffffffff
 282     return h
 283 _augment(ECBinCurve, _tmp)
 284
 285 class _tmp:
 286   def __repr__(me):
 287     if not me: return 'ECPt()'
 288     return 'ECPt(%s, %s)' % (me.ix, me.iy)
 289   def __str__(me):
 290     if not me: return 'inf'
 291     return '(%s, %s)' % (me.ix, me.iy)
 292 _augment(ECPt, _tmp)
 293
 294 class _tmp:
 295   def __repr__(me):
 296     return 'ECInfo(curve = %r, G = %r, r = %s, h = %s)' % \
 297            (me.curve, me.G, me.r, me.h)
 298   def __hash__(me):
 299     h = 0x9bedb8de
 300     h ^=   hash(me.curve)
 301     h ^= 2*hash(me.G) & 0xffffffff
 302     return h
 303   def group(me):
 304     return ECGroup(me)
 305 _augment(ECInfo, _tmp)
 306
 307 class _tmp:
 308   def __repr__(me):
 309     if not me: return '%r()' % (me.curve)
 310     return '%r(%s, %s)' % (me.curve, me.x, me.y)
 311   def __str__(me):
 312     if not me: return 'inf'
 313     return '(%s, %s)' % (me.x, me.y)
 314 _augment(ECPtCurve, _tmp)
 315
 316 ###--------------------------------------------------------------------------
 317 ### Key sizes.
 318
 319 class _tmp:
 320   def __repr__(me): return 'KeySZAny(%d)' % me.default
 321   def check(me, sz): return True
 322   def best(me, sz): return sz
 323 _augment(KeySZAny, _tmp)
 324
 325 class _tmp:
 326   def __repr__(me):
 327     return 'KeySZRange(%d, %d, %d, %d)' % \
 328            (me.default, me.min, me.max, me.mod)
 329   def check(me, sz): return me.min <= sz <= me.max and sz % me.mod == 0
 330   def best(me, sz):
 331     if sz < me.min: raise ValueError, 'key too small'
 332     elif sz > me.max: return me.max
 333     else: return sz - (sz % me.mod)
 334 _augment(KeySZRange, _tmp)
 335
 336 class _tmp:
 337   def __repr__(me): return 'KeySZSet(%d, %s)' % (me.default, me.set)
 338   def check(me, sz): return sz in me.set
 339   def best(me, sz):
 340     found = -1
 341     for i in me.set:
 342       if found < i <= sz: found = i
 343     if found < 0: raise ValueError, 'key too small'
 344     return found
 345 _augment(KeySZSet, _tmp)
 346
 347 ###--------------------------------------------------------------------------
 348 ### Abstract groups.
 349
 350 class _tmp:
 351   def __repr__(me):
 352     return '%s(p = %s, r = %s, g = %s)' % \
 353            (type(me).__name__, me.p, me.r, me.g)
 354 _augment(FGInfo, _tmp)
 355
 356 class _tmp:
 357   def group(me): return PrimeGroup(me)
 358 _augment(DHInfo, _tmp)
 359
 360 class _tmp:
 361   def group(me): return BinGroup(me)
 362 _augment(BinDHInfo, _tmp)
 363
 364 class _tmp:
 365   def __repr__(me):
 366     return '%s(%r)' % (type(me).__name__, me.info)
 367 _augment(Group, _tmp)
 368
 369 class _tmp:
 370   def __hash__(me):
 371     info = me.info
 372     h = 0xbce3cfe6
 373     h ^=   hash(info.p)
 374     h ^= 2*hash(info.r) & 0xffffffff
 375     h ^= 5*hash(info.g) & 0xffffffff
 376     return h
 377 _augment(PrimeGroup, _tmp)
 378
 379 class _tmp:
 380   def __hash__(me):
 381     info = me.info
 382     h = 0x80695949
 383     h ^=   hash(info.p)
 384     h ^= 2*hash(info.r) & 0xffffffff
 385     h ^= 5*hash(info.g) & 0xffffffff
 386     return h
 387 _augment(BinGroup, _tmp)
 388
 389 class _tmp:
 390   def __hash__(me): return 0x0ec23dab ^ hash(me.info)
 391 _augment(ECGroup, _tmp)
 392
 393 class _tmp:
 394   def __repr__(me):
 395     return '%r(%r)' % (me.group, str(me))
 396 _augment(GE, _tmp)
 397
 398 ###--------------------------------------------------------------------------
 399 ### RSA encoding techniques.
 400
 401 class PKCS1Crypt (object):
 402   def __init__(me, ep = '', rng = rand):
 403     me.ep = ep
 404     me.rng = rng
 405   def encode(me, msg, nbits):
 406     return _base._p1crypt_encode(msg, nbits, me.ep, me.rng)
 407   def decode(me, ct, nbits):
 408     return _base._p1crypt_decode(ct, nbits, me.ep, me.rng)
 409
 410 class PKCS1Sig (object):
 411   def __init__(me, ep = '', rng = rand):
 412     me.ep = ep
 413     me.rng = rng
 414   def encode(me, msg, nbits):
 415     return _base._p1sig_encode(msg, nbits, me.ep, me.rng)
 416   def decode(me, msg, sig, nbits):
 417     return _base._p1sig_decode(msg, sig, nbits, me.ep, me.rng)
 418
 419 class OAEP (object):
 420   def __init__(me, mgf = sha_mgf, hash = sha, ep = '', rng = rand):
 421     me.mgf = mgf
 422     me.hash = hash
 423     me.ep = ep
 424     me.rng = rng
 425   def encode(me, msg, nbits):
 426     return _base._oaep_encode(msg, nbits, me.mgf, me.hash, me.ep, me.rng)
 427   def decode(me, ct, nbits):
 428     return _base._oaep_decode(ct, nbits, me.mgf, me.hash, me.ep, me.rng)
 429
 430 class PSS (object):
 431   def __init__(me, mgf = sha_mgf, hash = sha, saltsz = None, rng = rand):
 432     me.mgf = mgf
 433     me.hash = hash
 434     if saltsz is None:
 435       saltsz = hash.hashsz
 436     me.saltsz = saltsz
 437     me.rng = rng
 438   def encode(me, msg, nbits):
 439     return _base._pss_encode(msg, nbits, me.mgf, me.hash, me.saltsz, me.rng)
 440   def decode(me, msg, sig, nbits):
 441     return _base._pss_decode(msg, sig, nbits,
 442                              me.mgf, me.hash, me.saltsz, me.rng)
 443
 444 class _tmp:
 445   def encrypt(me, msg, enc):
 446     return me.pubop(enc.encode(msg, me.n.nbits))
 447   def verify(me, msg, sig, enc):
 448     if msg is None: return enc.decode(msg, me.pubop(sig), me.n.nbits)
 449     try:
 450       x = enc.decode(msg, me.pubop(sig), me.n.nbits)
 451       return x is None or x == msg
 452     except ValueError:
 453       return False
 454 _augment(RSAPub, _tmp)
 455
 456 class _tmp:
 457   def decrypt(me, ct, enc): return enc.decode(me.privop(ct), me.n.nbits)
 458   def sign(me, msg, enc): return me.privop(enc.encode(msg, me.n.nbits))
 459 _augment(RSAPriv, _tmp)
 460
 461 ###--------------------------------------------------------------------------
 462 ### Bernstein's elliptic curve crypto and related schemes.
 463
 464 X25519_BASE = \
 465   bytes('0900000000000000000000000000000000000000000000000000000000000000')
 466
 467 X448_BASE = \
 468   bytes('05000000000000000000000000000000000000000000000000000000'
 469         '00000000000000000000000000000000000000000000000000000000')
 470
 471 Z128 = bytes('00000000000000000000000000000000')
 472
 473 class _BoxyPub (object):
 474   def __init__(me, pub, *kw, **kwargs):
 475     if len(pub) != me._PUBSZ: raise ValueError, 'bad public key'
 476     super(_BoxyPub, me).__init__(*kw, **kwargs)
 477     me.pub = pub
 478
 479 class _BoxyPriv (_BoxyPub):
 480   def __init__(me, priv, pub = None, *kw, **kwargs):
 481     if len(priv) != me._KEYSZ: raise ValueError, 'bad private key'
 482     if pub is None: pub = me._op(priv, me._BASE)
 483     super(_BoxyPriv, me).__init__(pub = pub, *kw, **kwargs)
 484     me.priv = priv
 485   def agree(me, you): return me._op(me.priv, you.pub)
 486   def boxkey(me, recip):
 487     return me._hashkey(me.agree(recip))
 488   def box(me, recip, n, m):
 489     return secret_box(me.boxkey(recip), n, m)
 490   def unbox(me, recip, n, c):
 491     return secret_unbox(me.boxkey(recip, n, c))
 492
 493 class X25519Pub (_BoxyPub):
 494   _PUBSZ = X25519_PUBSZ
 495   _BASE = X25519_BASE
 496
 497 class X25519Priv (_BoxyPriv, X25519Pub):
 498   _KEYSZ = X25519_KEYSZ
 499   def _op(me, k, X): return x25519(k, X)
 500   def _hashkey(me, z): return hsalsa20_prf(z, Z128)
 501
 502 class X448Pub (_BoxyPub):
 503   _PUBSZ = X448_PUBSZ
 504   _BASE = X448_BASE
 505
 506 class X448Priv (_BoxyPriv, X448Pub):
 507   _KEYSZ = X448_KEYSZ
 508   def _op(me, k, X): return x448(k, X)
 509   ##def _hashkey(me, z): return ???
 510
 511 class Ed25519Pub (object):
 512   def __init__(me, pub):
 513     me.pub = pub
 514   def verify(me, msg, sig):
 515     return ed25519_verify(me.pub, msg, sig)
 516
 517 class Ed25519Priv (Ed25519Pub):
 518   def __init__(me, priv):
 519     me.priv = priv
 520     Ed25519Pub.__init__(me, ed25519_pubkey(priv))
 521   def sign(me, msg):
 522     return ed25519_sign(me.priv, msg, pub = me.pub)
 523   @classmethod
 524   def generate(cls, rng = rand):
 525     return cls(rng.block(ED25519_KEYSZ))
 526
 527 ###--------------------------------------------------------------------------
 528 ### Built-in named curves and prime groups.
 529
 530 class _groupmap (object):
 531   def __init__(me, map, nth):
 532     me.map = map
 533     me.nth = nth
 534     me.i = [None] * (max(map.values()) + 1)
 535   def __repr__(me):
 536     return '{%s}' % ', '.join(['%r: %r' % (k, me[k]) for k in me])
 537   def __contains__(me, k):
 538     return k in me.map
 539   def __getitem__(me, k):
 540     i = me.map[k]
 541     if me.i[i] is None:
 542       me.i[i] = me.nth(i)
 543     return me.i[i]
 544   def __setitem__(me, k, v):
 545     raise TypeError, "immutable object"
 546   def __iter__(me):
 547     return iter(me.map)
 548   def iterkeys(me):
 549     return iter(me.map)
 550   def itervalues(me):
 551     for k in me:
 552       yield me[k]
 553   def iteritems(me):
 554     for k in me:
 555       yield k, me[k]
 556   def keys(me):
 557     return [k for k in me]
 558   def values(me):
 559     return [me[k] for k in me]
 560   def items(me):
 561     return [(k, me[k]) for k in me]
 562 eccurves = _groupmap(_base._eccurves, ECInfo._curven)
 563 primegroups = _groupmap(_base._pgroups, DHInfo._groupn)
 564 bingroups = _groupmap(_base._bingroups, BinDHInfo._groupn)
 565
 566 ###--------------------------------------------------------------------------
 567 ### Prime number generation.
 568
 569 class PrimeGenEventHandler (object):
 570   def pg_begin(me, ev):
 571     return me.pg_try(ev)
 572   def pg_done(me, ev):
 573     return PGEN_DONE
 574   def pg_abort(me, ev):
 575     return PGEN_TRY
 576   def pg_fail(me, ev):
 577     return PGEN_TRY
 578   def pg_pass(me, ev):
 579     return PGEN_TRY
 580
 581 class SophieGermainStepJump (object):
 582   def pg_begin(me, ev):
 583     me.lf = PrimeFilter(ev.x)
 584     me.hf = me.lf.muladd(2, 1)
 585     return me.cont(ev)
 586   def pg_try(me, ev):
 587     me.step()
 588     return me.cont(ev)
 589   def cont(me, ev):
 590     while me.lf.status == PGEN_FAIL or me.hf.status == PGEN_FAIL:
 591       me.step()
 592     if me.lf.status == PGEN_ABORT or me.hf.status == PGEN_ABORT:
 593       return PGEN_ABORT
 594     ev.x = me.lf.x
 595     if me.lf.status == PGEN_DONE and me.hf.status == PGEN_DONE:
 596       return PGEN_DONE
 597     return PGEN_TRY
 598   def pg_done(me, ev):
 599     del me.lf
 600     del me.hf
 601
 602 class SophieGermainStepper (SophieGermainStepJump):
 603   def __init__(me, step):
 604     me.lstep = step;
 605     me.hstep = 2 * step
 606   def step(me):
 607     me.lf.step(me.lstep)
 608     me.hf.step(me.hstep)
 609
 610 class SophieGermainJumper (SophieGermainStepJump):
 611   def __init__(me, jump):
 612     me.ljump = PrimeFilter(jump);
 613     me.hjump = me.ljump.muladd(2, 0)
 614   def step(me):
 615     me.lf.jump(me.ljump)
 616     me.hf.jump(me.hjump)
 617   def pg_done(me, ev):
 618     del me.ljump
 619     del me.hjump
 620     SophieGermainStepJump.pg_done(me, ev)
 621
 622 class SophieGermainTester (object):
 623   def __init__(me):
 624     pass
 625   def pg_begin(me, ev):
 626     me.lr = RabinMiller(ev.x)
 627     me.hr = RabinMiller(2 * ev.x + 1)
 628   def pg_try(me, ev):
 629     lst = me.lr.test(ev.rng.range(me.lr.x))
 630     if lst != PGEN_PASS and lst != PGEN_DONE:
 631       return lst
 632     rst = me.hr.test(ev.rng.range(me.hr.x))
 633     if rst != PGEN_PASS and rst != PGEN_DONE:
 634       return rst
 635     if lst == PGEN_DONE and rst == PGEN_DONE:
 636       return PGEN_DONE
 637     return PGEN_PASS
 638   def pg_done(me, ev):
 639     del me.lr
 640     del me.hr
 641
 642 class PrimitiveStepper (PrimeGenEventHandler):
 643   def __init__(me):
 644     pass
 645   def pg_try(me, ev):
 646     ev.x = me.i.next()
 647     return PGEN_TRY
 648   def pg_begin(me, ev):
 649     me.i = iter(smallprimes)
 650     return me.pg_try(ev)
 651
 652 class PrimitiveTester (PrimeGenEventHandler):
 653   def __init__(me, mod, hh = [], exp = None):
 654     me.mod = MPMont(mod)
 655     me.exp = exp
 656     me.hh = hh
 657   def pg_try(me, ev):
 658     x = ev.x
 659     if me.exp is not None:
 660       x = me.mod.exp(x, me.exp)
 661       if x == 1: return PGEN_FAIL
 662     for h in me.hh:
 663       if me.mod.exp(x, h) == 1: return PGEN_FAIL
 664     ev.x = x
 665     return PGEN_DONE
 666
 667 class SimulStepper (PrimeGenEventHandler):
 668   def __init__(me, mul = 2, add = 1, step = 2):
 669     me.step = step
 670     me.mul = mul
 671     me.add = add
 672   def _stepfn(me, step):
 673     if step <= 0:
 674       raise ValueError, 'step must be positive'
 675     if step <= MPW_MAX:
 676       return lambda f: f.step(step)
 677     j = PrimeFilter(step)
 678     return lambda f: f.jump(j)
 679   def pg_begin(me, ev):
 680     x = ev.x
 681     me.lf = PrimeFilter(x)
 682     me.hf = PrimeFilter(x * me.mul + me.add)
 683     me.lstep = me._stepfn(me.step)
 684     me.hstep = me._stepfn(me.step * me.mul)
 685     SimulStepper._cont(me, ev)
 686   def pg_try(me, ev):
 687     me._step()
 688     me._cont(ev)
 689   def _step(me):
 690     me.lstep(me.lf)
 691     me.hstep(me.hf)
 692   def _cont(me, ev):
 693     while me.lf.status == PGEN_FAIL or me.hf.status == PGEN_FAIL:
 694       me._step()
 695     if me.lf.status == PGEN_ABORT or me.hf.status == PGEN_ABORT:
 696       return PGEN_ABORT
 697     ev.x = me.lf.x
 698     if me.lf.status == PGEN_DONE and me.hf.status == PGEN_DONE:
 699       return PGEN_DONE
 700     return PGEN_TRY
 701   def pg_done(me, ev):
 702     del me.lf
 703     del me.hf
 704     del me.lstep
 705     del me.hstep
 706
 707 class SimulTester (PrimeGenEventHandler):
 708   def __init__(me, mul = 2, add = 1):
 709     me.mul = mul
 710     me.add = add
 711   def pg_begin(me, ev):
 712     x = ev.x
 713     me.lr = RabinMiller(x)
 714     me.hr = RabinMiller(x * me.mul + me.add)
 715   def pg_try(me, ev):
 716     lst = me.lr.test(ev.rng.range(me.lr.x))
 717     if lst != PGEN_PASS and lst != PGEN_DONE:
 718       return lst
 719     rst = me.hr.test(ev.rng.range(me.hr.x))
 720     if rst != PGEN_PASS and rst != PGEN_DONE:
 721       return rst
 722     if lst == PGEN_DONE and rst == PGEN_DONE:
 723       return PGEN_DONE
 724     return PGEN_PASS
 725   def pg_done(me, ev):
 726     del me.lr
 727     del me.hr
 728
 729 def sgprime(start, step = 2, name = 'p', event = pgen_nullev, nsteps = 0):
 730   start = MP(start)
 731   return pgen(start, name, SimulStepper(step = step), SimulTester(), event,
 732               nsteps, RabinMiller.iters(start.nbits))
 733
 734 def findprimitive(mod, hh = [], exp = None, name = 'g', event = pgen_nullev):
 735   return pgen(0, name, PrimitiveStepper(), PrimitiveTester(mod, hh, exp),
 736               event, 0, 1)
 737
 738 def kcdsaprime(pbits, qbits, rng = rand,
 739                event = pgen_nullev, name = 'p', nsteps = 0):
 740   hbits = pbits - qbits
 741   h = pgen(rng.mp(hbits, 1), name + ' [h]',
 742            PrimeGenStepper(2), PrimeGenTester(),
 743            event, nsteps, RabinMiller.iters(hbits))
 744   q = pgen(rng.mp(qbits, 1), name, SimulStepper(2 * h, 1, 2),
 745            SimulTester(2 * h, 1), event, nsteps, RabinMiller.iters(qbits))
 746   p = 2 * q * h + 1
 747   return p, q, h
 748
 749 #----- That's all, folks ----------------------------------------------------