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 from __future__ import with_statement
  27
  28 from binascii import hexlify as _hexify, unhexlify as _unhexify
  29 from contextlib import contextmanager as _ctxmgr
  30 try: import DLFCN as _dlfcn
  31 except ImportError: _dlfcn = None
  32 import os as _os
  33 from struct import pack as _pack
  34 import sys as _sys
  35 import types as _types
  36
  37 ###--------------------------------------------------------------------------
  38 ### Import the main C extension module.
  39
  40 try:
  41   _dlflags = _odlflags = _sys.getdlopenflags()
  42 except AttributeError:
  43   _dlflags = _odlflags = -1
  44
  45 ## Set the `deep binding' flag.  Python has its own different MD5
  46 ## implementation, and some distributions export `md5_init' and friends so
  47 ## they override our versions, which doesn't end well.  Figure out how to
  48 ## turn this flag on so we don't have the problem.
  49 if _dlflags >= 0:
  50   try: _dlflags |= _dlfcn.RTLD_DEEPBIND
  51   except AttributeError:
  52     try: _dlflags |= _os.RTLD_DEEPBIND
  53     except AttributeError:
  54       if _os.uname()[0] == 'Linux': _dlflags |= 8 # magic knowledge
  55       else: pass # can't do this.
  56   _sys.setdlopenflags(_dlflags)
  57
  58 import _base
  59
  60 if _odlflags >= 0:
  61   _sys.setdlopenflags(_odlflags)
  62
  63 del _dlflags, _odlflags
  64
  65 ###--------------------------------------------------------------------------
  66 ### Basic stuff.
  67
  68 ## For the benefit of the default keyreporter, we need the program name.
  69 _base._ego(_sys.argv[0])
  70
  71 ## Register our module.
  72 _base._set_home_module(_sys.modules[__name__])
  73 def default_lostexchook(why, ty, val, tb):
  74   """`catacomb.lostexchook(WHY, TY, VAL, TB)' reports lost exceptions."""
  75   _sys.stderr.write("\n\n!!! LOST EXCEPTION: %s\n" % why)
  76   _sys.excepthook(ty, val, tb)
  77   _sys.stderr.write("\n")
  78 lostexchook = default_lostexchook
  79
  80 ## How to fix a name back into the right identifier.  Alas, the rules are not
  81 ## consistent.
  82 def _fixname(name):
  83
  84   ## Hyphens consistently become underscores.
  85   name = name.replace('-', '_')
  86
  87   ## But slashes might become underscores or just vanish.
  88   if name.startswith('salsa20'): name = name.replace('/', '')
  89   else: name = name.replace('/', '_')
  90
  91   ## Done.
  92   return name
  93
  94 ## Initialize the module.  Drag in the static methods of the various
  95 ## classes; create names for the various known crypto algorithms.
  96 def _init():
  97   d = globals()
  98   b = _base.__dict__;
  99   for i in b:
 100     if i[0] != '_':
 101       d[i] = b[i];
 102   for i in [gcciphers, gcaeads, gchashes, gcmacs, gcprps]:
 103     for c in i.itervalues():
 104       d[_fixname(c.name)] = c
 105   for c in gccrands.itervalues():
 106     d[_fixname(c.name + 'rand')] = c
 107 _init()
 108
 109 ## A handy function for our work: add the methods of a named class to an
 110 ## existing class.  This is how we write the Python-implemented parts of our
 111 ## mostly-C types.
 112 def _augment(c, cc):
 113   for i in cc.__dict__:
 114     a = cc.__dict__[i]
 115     if type(a) is _types.MethodType:
 116       a = a.im_func
 117     elif type(a) not in (_types.FunctionType, staticmethod, classmethod):
 118       continue
 119     setattr(c, i, a)
 120
 121 ## Parsing functions tend to return the object parsed and the remainder of
 122 ## the input.  This checks that the remainder is input and, if so, returns
 123 ## just the object.
 124 def _checkend(r):
 125   x, rest = r
 126   if rest != '':
 127     raise SyntaxError, 'junk at end of string'
 128   return x
 129
 130 ## Some pretty-printing utilities.
 131 PRINT_SECRETS = False
 132 def _clsname(me): return type(me).__name__
 133 def _repr_secret(thing, secretp = True):
 134   if not secretp or PRINT_SECRETS: return repr(thing)
 135   else: return '#<SECRET>'
 136 def _pp_str(me, pp, cyclep): pp.text(cyclep and '...' or str(me))
 137 def _pp_secret(pp, thing, secretp = True):
 138   if not secretp or PRINT_SECRETS: pp.pretty(thing)
 139   else: pp.text('#<SECRET>')
 140 def _pp_bgroup(pp, text):
 141   ind = len(text)
 142   pp.begin_group(ind, text)
 143   return ind
 144 def _pp_bgroup_tyname(pp, obj, open = '('):
 145   return _pp_bgroup(pp, _clsname(obj) + open)
 146 def _pp_kv(pp, k, v, secretp = False):
 147   ind = _pp_bgroup(pp, k + ' = ')
 148   _pp_secret(pp, v, secretp)
 149   pp.end_group(ind, '')
 150 def _pp_commas(pp, printfn, items):
 151   firstp = True
 152   for i in items:
 153     if firstp: firstp = False
 154     else: pp.text(','); pp.breakable()
 155     printfn(i)
 156 def _pp_dict(pp, items):
 157   def p((k, v)):
 158     pp.begin_group(0)
 159     pp.pretty(k)
 160     pp.text(':')
 161     pp.begin_group(2)
 162     pp.breakable()
 163     pp.pretty(v)
 164     pp.end_group(2)
 165     pp.end_group(0)
 166   _pp_commas(pp, p, items)
 167
 168 ###--------------------------------------------------------------------------
 169 ### Bytestrings.
 170
 171 class _tmp:
 172   def fromhex(x):
 173     return ByteString(_unhexify(x))
 174   fromhex = staticmethod(fromhex)
 175   def __hex__(me):
 176     return _hexify(me)
 177   def __repr__(me):
 178     return 'bytes(%r)' % hex(me)
 179 _augment(ByteString, _tmp)
 180 ByteString.__hash__ = str.__hash__
 181 bytes = ByteString.fromhex
 182
 183 ###--------------------------------------------------------------------------
 184 ### Symmetric encryption.
 185
 186 class _tmp:
 187   def encrypt(me, n, m, tsz = None, h = ByteString('')):
 188     if tsz is None: tsz = me.__class__.tagsz.default
 189     e = me.enc(n, len(h), len(m), tsz)
 190     if not len(h): a = None
 191     else: a = e.aad().hash(h)
 192     c0 = e.encrypt(m)
 193     c1, t = e.done(aad = a)
 194     return c0 + c1, t
 195   def decrypt(me, n, c, t, h = ByteString('')):
 196     d = me.dec(n, len(h), len(c), len(t))
 197     if not len(h): a = None
 198     else: a = d.aad().hash(h)
 199     m = d.decrypt(c)
 200     m += d.done(t, aad = a)
 201     return m
 202 _augment(GAEKey, _tmp)
 203
 204 ###--------------------------------------------------------------------------
 205 ### Hashing.
 206
 207 class _tmp:
 208   def check(me, h):
 209     hh = me.done()
 210     return ctstreq(h, hh)
 211 _augment(GHash, _tmp)
 212 _augment(Poly1305Hash, _tmp)
 213
 214 class _HashBase (object):
 215   ## The standard hash methods.  Assume that `hash' is defined and returns
 216   ## the receiver.
 217   def _check_range(me, n, max):
 218     if not (0 <= n <= max): raise OverflowError("out of range")
 219   def hashu8(me, n):
 220     me._check_range(n, 0xff)
 221     return me.hash(_pack('B', n))
 222   def hashu16l(me, n):
 223     me._check_range(n, 0xffff)
 224     return me.hash(_pack('<H', n))
 225   def hashu16b(me, n):
 226     me._check_range(n, 0xffff)
 227     return me.hash(_pack('>H', n))
 228   hashu16 = hashu16b
 229   def hashu32l(me, n):
 230     me._check_range(n, 0xffffffff)
 231     return me.hash(_pack('<L', n))
 232   def hashu32b(me, n):
 233     me._check_range(n, 0xffffffff)
 234     return me.hash(_pack('>L', n))
 235   hashu32 = hashu32b
 236   def hashu64l(me, n):
 237     me._check_range(n, 0xffffffffffffffff)
 238     return me.hash(_pack('<Q', n))
 239   def hashu64b(me, n):
 240     me._check_range(n, 0xffffffffffffffff)
 241     return me.hash(_pack('>Q', n))
 242   hashu64 = hashu64b
 243   def hashbuf8(me, s): return me.hashu8(len(s)).hash(s)
 244   def hashbuf16l(me, s): return me.hashu16l(len(s)).hash(s)
 245   def hashbuf16b(me, s): return me.hashu16b(len(s)).hash(s)
 246   hashbuf16 = hashbuf16b
 247   def hashbuf32l(me, s): return me.hashu32l(len(s)).hash(s)
 248   def hashbuf32b(me, s): return me.hashu32b(len(s)).hash(s)
 249   hashbuf32 = hashbuf32b
 250   def hashbuf64l(me, s): return me.hashu64l(len(s)).hash(s)
 251   def hashbuf64b(me, s): return me.hashu64b(len(s)).hash(s)
 252   hashbuf64 = hashbuf64b
 253   def hashstrz(me, s): return me.hash(s).hashu8(0)
 254
 255 class _ShakeBase (_HashBase):
 256
 257   ## Python gets really confused if I try to augment `__new__' on native
 258   ## classes, so wrap and delegate.  Sorry.
 259   def __init__(me, perso = '', *args, **kw):
 260     super(_ShakeBase, me).__init__(*args, **kw)
 261     me._h = me._SHAKE(perso = perso, func = me._FUNC)
 262
 263   ## Delegate methods...
 264   def copy(me): new = me.__class__._bare_new(); new._copy(me); return new
 265   def _copy(me, other): me._h = other._h.copy()
 266   def hash(me, m): me._h.hash(m); return me
 267   def xof(me): me._h.xof(); return me
 268   def get(me, n): return me._h.get(n)
 269   def mask(me, m): return me._h.mask(m)
 270   def done(me, n): return me._h.done(n)
 271   def check(me, h): return ctstreq(h, me.done(len(h)))
 272   @property
 273   def state(me): return me._h.state
 274   @property
 275   def buffered(me): return me._h.buffered
 276   @property
 277   def rate(me): return me._h.rate
 278   @classmethod
 279   def _bare_new(cls): return cls()
 280
 281 class _tmp:
 282   def check(me, h):
 283     return ctstreq(h, me.done(len(h)))
 284   def leftenc(me, n):
 285     nn = MP(n).storeb()
 286     return me.hashu8(len(nn)).hash(nn)
 287   def rightenc(me, n):
 288     nn = MP(n).storeb()
 289     return me.hash(nn).hashu8(len(nn))
 290   def stringenc(me, str):
 291     return me.leftenc(8*len(str)).hash(str)
 292   def bytepad_before(me):
 293     return me.leftenc(me.rate)
 294   def bytepad_after(me):
 295     if me.buffered: me.hash(me._Z[:me.rate - me.buffered])
 296     return me
 297   @_ctxmgr
 298   def bytepad(me):
 299     me.bytepad_before()
 300     yield me
 301     me.bytepad_after()
 302 _augment(Shake, _tmp)
 303 _augment(_ShakeBase, _tmp)
 304 Shake._Z = _ShakeBase._Z = ByteString.zero(200)
 305
 306 class KMAC (_ShakeBase):
 307   _FUNC = 'KMAC'
 308   def __init__(me, k, *arg, **kw):
 309     super(KMAC, me).__init__(*arg, **kw)
 310     with me.bytepad(): me.stringenc(k)
 311   def done(me, n = -1):
 312     if n < 0: n = me._TAGSZ
 313     me.rightenc(8*n)
 314     return super(KMAC, me).done(n)
 315   def xof(me):
 316     me.rightenc(0)
 317     return super(KMAC, me).xof()
 318   @classmethod
 319   def _bare_new(cls): return cls("")
 320
 321 class KMAC128 (KMAC): _SHAKE = Shake128; _TAGSZ = 16
 322 class KMAC256 (KMAC): _SHAKE = Shake256; _TAGSZ = 32
 323
 324 ###--------------------------------------------------------------------------
 325 ### NaCl `secretbox'.
 326
 327 def secret_box(k, n, m):
 328   y, t = salsa20_naclbox(k).encrypt(n, m)
 329   return t + y
 330
 331 def secret_unbox(k, n, c):
 332   tsz = poly1305.tagsz
 333   return salsa20_naclbox(k).decrypt(n, c[tsz:], c[0:tsz])
 334
 335 ###--------------------------------------------------------------------------
 336 ### Multiprecision integers and binary polynomials.
 337
 338 def _split_rat(x):
 339   if isinstance(x, BaseRat): return x._n, x._d
 340   else: return x, 1
 341 class BaseRat (object):
 342   """Base class implementing fields of fractions over Euclidean domains."""
 343   def __new__(cls, a, b):
 344     a, b = cls.RING(a), cls.RING(b)
 345     q, r = divmod(a, b)
 346     if r == 0: return q
 347     g = b.gcd(r)
 348     me = super(BaseRat, cls).__new__(cls)
 349     me._n = a//g
 350     me._d = b//g
 351     return me
 352   @property
 353   def numer(me): return me._n
 354   @property
 355   def denom(me): return me._d
 356   def __str__(me): return '%s/%s' % (me._n, me._d)
 357   def __repr__(me): return '%s(%s, %s)' % (_clsname(me), me._n, me._d)
 358   _repr_pretty_ = _pp_str
 359
 360   def __add__(me, you):
 361     n, d = _split_rat(you)
 362     return type(me)(me._n*d + n*me._d, d*me._d)
 363   __radd__ = __add__
 364   def __sub__(me, you):
 365     n, d = _split_rat(you)
 366     return type(me)(me._n*d - n*me._d, d*me._d)
 367   def __rsub__(me, you):
 368     n, d = _split_rat(you)
 369     return type(me)(n*me._d - me._n*d, d*me._d)
 370   def __mul__(me, you):
 371     n, d = _split_rat(you)
 372     return type(me)(me._n*n, me._d*d)
 373   __rmul__ = __mul__
 374   def __truediv__(me, you):
 375     n, d = _split_rat(you)
 376     return type(me)(me._n*d, me._d*n)
 377   def __rtruediv__(me, you):
 378     n, d = _split_rat(you)
 379     return type(me)(me._d*n, me._n*d)
 380   __div__ = __truediv__
 381   __rdiv__ = __rtruediv__
 382   def __cmp__(me, you):
 383     n, d = _split_rat(you)
 384     return cmp(me._n*d, n*me._d)
 385   def __rcmp__(me, you):
 386     n, d = _split_rat(you)
 387     return cmp(n*me._d, me._n*d)
 388
 389 class IntRat (BaseRat):
 390   RING = MP
 391
 392 class GFRat (BaseRat):
 393   RING = GF
 394
 395 class _tmp:
 396   def negp(x): return x < 0
 397   def posp(x): return x > 0
 398   def zerop(x): return x == 0
 399   def oddp(x): return x.testbit(0)
 400   def evenp(x): return not x.testbit(0)
 401   def mont(x): return MPMont(x)
 402   def barrett(x): return MPBarrett(x)
 403   def reduce(x): return MPReduce(x)
 404   def __truediv__(me, you): return IntRat(me, you)
 405   def __rtruediv__(me, you): return IntRat(you, me)
 406   __div__ = __truediv__
 407   __rdiv__ = __rtruediv__
 408   _repr_pretty_ = _pp_str
 409 _augment(MP, _tmp)
 410
 411 class _tmp:
 412   def zerop(x): return x == 0
 413   def reduce(x): return GFReduce(x)
 414   def trace(x, y): return x.reduce().trace(y)
 415   def halftrace(x, y): return x.reduce().halftrace(y)
 416   def modsqrt(x, y): return x.reduce().sqrt(y)
 417   def quadsolve(x, y): return x.reduce().quadsolve(y)
 418   def __truediv__(me, you): return GFRat(me, you)
 419   def __rtruediv__(me, you): return GFRat(you, me)
 420   __div__ = __truediv__
 421   __rdiv__ = __rtruediv__
 422   _repr_pretty_ = _pp_str
 423 _augment(GF, _tmp)
 424
 425 class _tmp:
 426   def product(*arg):
 427     'product(ITERABLE) or product(I, ...) -> PRODUCT'
 428     return MPMul(*arg).done()
 429   product = staticmethod(product)
 430 _augment(MPMul, _tmp)
 431
 432 ###--------------------------------------------------------------------------
 433 ### Abstract fields.
 434
 435 class _tmp:
 436   def fromstring(str): return _checkend(Field.parse(str))
 437   fromstring = staticmethod(fromstring)
 438 _augment(Field, _tmp)
 439
 440 class _tmp:
 441   def __repr__(me): return '%s(%sL)' % (_clsname(me), me.p)
 442   def __hash__(me): return 0x114401de ^ hash(me.p)
 443   def _repr_pretty_(me, pp, cyclep):
 444     ind = _pp_bgroup_tyname(pp, me)
 445     if cyclep: pp.text('...')
 446     else: pp.pretty(me.p)
 447     pp.end_group(ind, ')')
 448   def ec(me, a, b): return ECPrimeProjCurve(me, a, b)
 449 _augment(PrimeField, _tmp)
 450
 451 class _tmp:
 452   def __repr__(me): return '%s(%#xL)' % (_clsname(me), me.p)
 453   def ec(me, a, b): return ECBinProjCurve(me, a, b)
 454   def _repr_pretty_(me, pp, cyclep):
 455     ind = _pp_bgroup_tyname(pp, me)
 456     if cyclep: pp.text('...')
 457     else: pp.text('%#x' % me.p)
 458     pp.end_group(ind, ')')
 459 _augment(BinField, _tmp)
 460
 461 class _tmp:
 462   def __hash__(me): return 0x23e4701c ^ hash(me.p)
 463 _augment(BinPolyField, _tmp)
 464
 465 class _tmp:
 466   def __hash__(me):
 467     h = 0x9a7d6240
 468     h ^=   hash(me.p)
 469     h ^= 2*hash(me.beta) & 0xffffffff
 470     return h
 471 _augment(BinNormField, _tmp)
 472
 473 class _tmp:
 474   def __str__(me): return str(me.value)
 475   def __repr__(me): return '%s(%s)' % (repr(me.field), repr(me.value))
 476   _repr_pretty_ = _pp_str
 477 _augment(FE, _tmp)
 478
 479 ###--------------------------------------------------------------------------
 480 ### Elliptic curves.
 481
 482 class _tmp:
 483   def __repr__(me):
 484     return '%s(%r, %s, %s)' % (_clsname(me), me.field, me.a, me.b)
 485   def _repr_pretty_(me, pp, cyclep):
 486     ind = _pp_bgroup_tyname(pp, me)
 487     if cyclep:
 488       pp.text('...')
 489     else:
 490       pp.pretty(me.field); pp.text(','); pp.breakable()
 491       pp.pretty(me.a); pp.text(','); pp.breakable()
 492       pp.pretty(me.b)
 493     pp.end_group(ind, ')')
 494   def frombuf(me, s):
 495     return ecpt.frombuf(me, s)
 496   def fromraw(me, s):
 497     return ecpt.fromraw(me, s)
 498   def pt(me, *args):
 499     return me(*args)
 500 _augment(ECCurve, _tmp)
 501
 502 class _tmp:
 503   def __hash__(me):
 504     h = 0x6751d341
 505     h ^=   hash(me.field)
 506     h ^= 2*hash(me.a) ^ 0xffffffff
 507     h ^= 5*hash(me.b) ^ 0xffffffff
 508     return h
 509 _augment(ECPrimeCurve, _tmp)
 510
 511 class _tmp:
 512   def __hash__(me):
 513     h = 0x2ac203c5
 514     h ^=   hash(me.field)
 515     h ^= 2*hash(me.a) ^ 0xffffffff
 516     h ^= 5*hash(me.b) ^ 0xffffffff
 517     return h
 518 _augment(ECBinCurve, _tmp)
 519
 520 class _tmp:
 521   def __repr__(me):
 522     if not me: return '%s()' % _clsname(me)
 523     return '%s(%s, %s)' % (_clsname(me), me.ix, me.iy)
 524   def __str__(me):
 525     if not me: return 'inf'
 526     return '(%s, %s)' % (me.ix, me.iy)
 527   def _repr_pretty_(me, pp, cyclep):
 528     if cyclep:
 529       pp.text('...')
 530     elif not me:
 531       pp.text('inf')
 532     else:
 533       ind = _pp_bgroup(pp, '(')
 534       pp.pretty(me.ix); pp.text(','); pp.breakable()
 535       pp.pretty(me.iy)
 536       pp.end_group(ind, ')')
 537 _augment(ECPt, _tmp)
 538
 539 class _tmp:
 540   def __repr__(me):
 541     return '%s(curve = %r, G = %r, r = %s, h = %s)' % \
 542            (_clsname(me), me.curve, me.G, me.r, me.h)
 543   def _repr_pretty_(me, pp, cyclep):
 544     ind = _pp_bgroup_tyname(pp, me)
 545     if cyclep:
 546       pp.text('...')
 547     else:
 548       _pp_kv(pp, 'curve', me.curve); pp.text(','); pp.breakable()
 549       _pp_kv(pp, 'G', me.G); pp.text(','); pp.breakable()
 550       _pp_kv(pp, 'r', me.r); pp.text(','); pp.breakable()
 551       _pp_kv(pp, 'h', me.h)
 552     pp.end_group(ind, ')')
 553   def __hash__(me):
 554     h = 0x9bedb8de
 555     h ^=   hash(me.curve)
 556     h ^= 2*hash(me.G) & 0xffffffff
 557     return h
 558   def group(me):
 559     return ECGroup(me)
 560 _augment(ECInfo, _tmp)
 561
 562 class _tmp:
 563   def __repr__(me):
 564     if not me: return '%r()' % (me.curve)
 565     return '%r(%s, %s)' % (me.curve, me.x, me.y)
 566   def __str__(me):
 567     if not me: return 'inf'
 568     return '(%s, %s)' % (me.x, me.y)
 569   def _repr_pretty_(me, pp, cyclep):
 570     if cyclep:
 571       pp.text('...')
 572     elif not me:
 573       pp.text('inf')
 574     else:
 575       ind = _pp_bgroup(pp, '(')
 576       pp.pretty(me.x); pp.text(','); pp.breakable()
 577       pp.pretty(me.y)
 578       pp.end_group(ind, ')')
 579 _augment(ECPtCurve, _tmp)
 580
 581 ###--------------------------------------------------------------------------
 582 ### Key sizes.
 583
 584 class _tmp:
 585   def __repr__(me): return '%s(%d)' % (_clsname(me), me.default)
 586   def check(me, sz): return True
 587   def best(me, sz): return sz
 588   def pad(me, sz): return sz
 589 _augment(KeySZAny, _tmp)
 590
 591 class _tmp:
 592   def __repr__(me):
 593     return '%s(%d, %d, %d, %d)' % \
 594            (_clsname(me), me.default, me.min, me.max, me.mod)
 595   def _repr_pretty_(me, pp, cyclep):
 596     ind = _pp_bgroup_tyname(pp, me)
 597     if cyclep:
 598       pp.text('...')
 599     else:
 600       pp.pretty(me.default); pp.text(','); pp.breakable()
 601       pp.pretty(me.min); pp.text(','); pp.breakable()
 602       pp.pretty(me.max); pp.text(','); pp.breakable()
 603       pp.pretty(me.mod)
 604     pp.end_group(ind, ')')
 605   def check(me, sz): return me.min <= sz <= me.max and sz%me.mod == 0
 606   def best(me, sz):
 607     if sz < me.min: raise ValueError, 'key too small'
 608     elif sz > me.max: return me.max
 609     else: return sz - sz%me.mod
 610   def pad(me, sz):
 611     if sz > me.max: raise ValueError, 'key too large'
 612     elif sz < me.min: return me.min
 613     else: sz += me.mod - 1; return sz - sz%me.mod
 614 _augment(KeySZRange, _tmp)
 615
 616 class _tmp:
 617   def __repr__(me): return '%s(%d, %s)' % (_clsname(me), me.default, me.set)
 618   def _repr_pretty_(me, pp, cyclep):
 619     ind = _pp_bgroup_tyname(pp, me)
 620     if cyclep:
 621       pp.text('...')
 622     else:
 623       pp.pretty(me.default); pp.text(','); pp.breakable()
 624       ind1 = _pp_bgroup(pp, '{')
 625       _pp_commas(pp, pp.pretty, me.set)
 626       pp.end_group(ind1, '}')
 627     pp.end_group(ind, ')')
 628   def check(me, sz): return sz in me.set
 629   def best(me, sz):
 630     found = -1
 631     for i in me.set:
 632       if found < i <= sz: found = i
 633     if found < 0: raise ValueError, 'key too small'
 634     return found
 635   def pad(me, sz):
 636     found = -1
 637     for i in me.set:
 638       if sz <= i and (found == -1 or i < found): found = i
 639     if found < 0: raise ValueError, 'key too large'
 640     return found
 641 _augment(KeySZSet, _tmp)
 642
 643 ###--------------------------------------------------------------------------
 644 ### Key data objects.
 645
 646 class _tmp:
 647   def __repr__(me): return '%s(%r)' % (_clsname(me), me.name)
 648 _augment(KeyFile, _tmp)
 649
 650 class _tmp:
 651   def __repr__(me): return '%s(%r)' % (_clsname(me), me.fulltag)
 652 _augment(Key, _tmp)
 653
 654 class _tmp:
 655   def __repr__(me):
 656     return '%s({%s})' % (_clsname(me),
 657                          ', '.join(['%r: %r' % kv for kv in me.iteritems()]))
 658   def _repr_pretty_(me, pp, cyclep):
 659     ind = _pp_bgroup_tyname(pp, me)
 660     if cyclep: pp.text('...')
 661     else: _pp_dict(pp, me.iteritems())
 662     pp.end_group(ind, ')')
 663 _augment(KeyAttributes, _tmp)
 664
 665 class _tmp:
 666   def __repr__(me):
 667     return '%s(%s, %r)' % (_clsname(me),
 668                            _repr_secret(me._guts(),
 669                                         not (me.flags & KF_NONSECRET)),
 670                            me.writeflags(me.flags))
 671   def _repr_pretty_(me, pp, cyclep):
 672     ind = _pp_bgroup_tyname(pp, me)
 673     if cyclep:
 674       pp.text('...')
 675     else:
 676       _pp_secret(pp, me._guts(), not (me.flags & KF_NONSECRET))
 677       pp.text(','); pp.breakable()
 678       pp.pretty(me.writeflags(me.flags))
 679     pp.end_group(ind, ')')
 680 _augment(KeyData, _tmp)
 681
 682 class _tmp:
 683   def _guts(me): return me.bin
 684 _augment(KeyDataBinary, _tmp)
 685
 686 class _tmp:
 687   def _guts(me): return me.ct
 688 _augment(KeyDataEncrypted, _tmp)
 689
 690 class _tmp:
 691   def _guts(me): return me.mp
 692 _augment(KeyDataMP, _tmp)
 693
 694 class _tmp:
 695   def _guts(me): return me.str
 696 _augment(KeyDataString, _tmp)
 697
 698 class _tmp:
 699   def _guts(me): return me.ecpt
 700 _augment(KeyDataECPt, _tmp)
 701
 702 class _tmp:
 703   def __repr__(me):
 704     return '%s({%s})' % (_clsname(me),
 705                          ', '.join(['%r: %r' % kv for kv in me.iteritems()]))
 706   def _repr_pretty_(me, pp, cyclep):
 707     ind = _pp_bgroup_tyname(pp, me, '({ ')
 708     if cyclep: pp.text('...')
 709     else: _pp_dict(pp, me.iteritems())
 710     pp.end_group(ind, ' })')
 711 _augment(KeyDataStructured, _tmp)
 712
 713 ###--------------------------------------------------------------------------
 714 ### Abstract groups.
 715
 716 class _tmp:
 717   def __repr__(me):
 718     return '%s(p = %s, r = %s, g = %s)' % (_clsname(me), me.p, me.r, me.g)
 719   def _repr_pretty_(me, pp, cyclep):
 720     ind = _pp_bgroup_tyname(pp, me)
 721     if cyclep:
 722       pp.text('...')
 723     else:
 724       _pp_kv(pp, 'p', me.p); pp.text(','); pp.breakable()
 725       _pp_kv(pp, 'r', me.r); pp.text(','); pp.breakable()
 726       _pp_kv(pp, 'g', me.g)
 727     pp.end_group(ind, ')')
 728 _augment(FGInfo, _tmp)
 729
 730 class _tmp:
 731   def group(me): return PrimeGroup(me)
 732 _augment(DHInfo, _tmp)
 733
 734 class _tmp:
 735   def group(me): return BinGroup(me)
 736 _augment(BinDHInfo, _tmp)
 737
 738 class _tmp:
 739   def __repr__(me):
 740     return '%s(%r)' % (_clsname(me), me.info)
 741   def _repr_pretty_(me, pp, cyclep):
 742     ind = _pp_bgroup_tyname(pp, me)
 743     if cyclep: pp.text('...')
 744     else: pp.pretty(me.info)
 745     pp.end_group(ind, ')')
 746 _augment(Group, _tmp)
 747
 748 class _tmp:
 749   def __hash__(me):
 750     info = me.info
 751     h = 0xbce3cfe6
 752     h ^=   hash(info.p)
 753     h ^= 2*hash(info.r) & 0xffffffff
 754     h ^= 5*hash(info.g) & 0xffffffff
 755     return h
 756   def _get_geval(me, x): return MP(x)
 757 _augment(PrimeGroup, _tmp)
 758
 759 class _tmp:
 760   def __hash__(me):
 761     info = me.info
 762     h = 0x80695949
 763     h ^=   hash(info.p)
 764     h ^= 2*hash(info.r) & 0xffffffff
 765     h ^= 5*hash(info.g) & 0xffffffff
 766     return h
 767   def _get_geval(me, x): return GF(x)
 768 _augment(BinGroup, _tmp)
 769
 770 class _tmp:
 771   def __hash__(me): return 0x0ec23dab ^ hash(me.info)
 772   def _get_geval(me, x): return x.toec()
 773 _augment(ECGroup, _tmp)
 774
 775 class _tmp:
 776   def __repr__(me):
 777     return '%r(%r)' % (me.group, str(me))
 778   def _repr_pretty_(me, pp, cyclep):
 779     pp.pretty(type(me)._get_geval(me))
 780 _augment(GE, _tmp)
 781
 782 ###--------------------------------------------------------------------------
 783 ### RSA encoding techniques.
 784
 785 class PKCS1Crypt (object):
 786   def __init__(me, ep = '', rng = rand):
 787     me.ep = ep
 788     me.rng = rng
 789   def encode(me, msg, nbits):
 790     return _base._p1crypt_encode(msg, nbits, me.ep, me.rng)
 791   def decode(me, ct, nbits):
 792     return _base._p1crypt_decode(ct, nbits, me.ep, me.rng)
 793
 794 class PKCS1Sig (object):
 795   def __init__(me, ep = '', rng = rand):
 796     me.ep = ep
 797     me.rng = rng
 798   def encode(me, msg, nbits):
 799     return _base._p1sig_encode(msg, nbits, me.ep, me.rng)
 800   def decode(me, msg, sig, nbits):
 801     return _base._p1sig_decode(msg, sig, nbits, me.ep, me.rng)
 802
 803 class OAEP (object):
 804   def __init__(me, mgf = sha_mgf, hash = sha, ep = '', rng = rand):
 805     me.mgf = mgf
 806     me.hash = hash
 807     me.ep = ep
 808     me.rng = rng
 809   def encode(me, msg, nbits):
 810     return _base._oaep_encode(msg, nbits, me.mgf, me.hash, me.ep, me.rng)
 811   def decode(me, ct, nbits):
 812     return _base._oaep_decode(ct, nbits, me.mgf, me.hash, me.ep, me.rng)
 813
 814 class PSS (object):
 815   def __init__(me, mgf = sha_mgf, hash = sha, saltsz = None, rng = rand):
 816     me.mgf = mgf
 817     me.hash = hash
 818     if saltsz is None:
 819       saltsz = hash.hashsz
 820     me.saltsz = saltsz
 821     me.rng = rng
 822   def encode(me, msg, nbits):
 823     return _base._pss_encode(msg, nbits, me.mgf, me.hash, me.saltsz, me.rng)
 824   def decode(me, msg, sig, nbits):
 825     return _base._pss_decode(msg, sig, nbits,
 826                              me.mgf, me.hash, me.saltsz, me.rng)
 827
 828 class _tmp:
 829   def encrypt(me, msg, enc):
 830     return me.pubop(enc.encode(msg, me.n.nbits))
 831   def verify(me, msg, sig, enc):
 832     if msg is None: return enc.decode(msg, me.pubop(sig), me.n.nbits)
 833     try:
 834       x = enc.decode(msg, me.pubop(sig), me.n.nbits)
 835       return x is None or x == msg
 836     except ValueError:
 837       return False
 838   def __repr__(me):
 839     return '%s(n = %r, e = %r)' % (_clsname(me), me.n, me.e)
 840   def _repr_pretty_(me, pp, cyclep):
 841     ind = _pp_bgroup_tyname(pp, me)
 842     if cyclep:
 843       pp.text('...')
 844     else:
 845       _pp_kv(pp, 'n', me.n); pp.text(','); pp.breakable()
 846       _pp_kv(pp, 'e', me.e)
 847     pp.end_group(ind, ')')
 848 _augment(RSAPub, _tmp)
 849
 850 class _tmp:
 851   def decrypt(me, ct, enc): return enc.decode(me.privop(ct), me.n.nbits)
 852   def sign(me, msg, enc): return me.privop(enc.encode(msg, me.n.nbits))
 853   def __repr__(me):
 854     return '%s(n = %r, e = %r, d = %s, ' \
 855       'p = %s, q = %s, dp = %s, dq = %s, q_inv = %s)' % \
 856       (_clsname(me), me.n, me.e,
 857        _repr_secret(me.d), _repr_secret(me.p), _repr_secret(me.q),
 858        _repr_secret(me.dp), _repr_secret(me.dq), _repr_secret(me.q_inv))
 859   def _repr_pretty_(me, pp, cyclep):
 860     ind = _pp_bgroup_tyname(pp, me)
 861     if cyclep:
 862       pp.text('...')
 863     else:
 864       _pp_kv(pp, 'n', me.n); pp.text(','); pp.breakable()
 865       _pp_kv(pp, 'e', me.e); pp.text(','); pp.breakable()
 866       _pp_kv(pp, 'd', me.d, secretp = True); pp.text(','); pp.breakable()
 867       _pp_kv(pp, 'p', me.p, secretp = True); pp.text(','); pp.breakable()
 868       _pp_kv(pp, 'q', me.q, secretp = True); pp.text(','); pp.breakable()
 869       _pp_kv(pp, 'dp', me.dp, secretp = True); pp.text(','); pp.breakable()
 870       _pp_kv(pp, 'dq', me.dq, secretp = True); pp.text(','); pp.breakable()
 871       _pp_kv(pp, 'q_inv', me.q_inv, secretp = True)
 872     pp.end_group(ind, ')')
 873 _augment(RSAPriv, _tmp)
 874
 875 ###--------------------------------------------------------------------------
 876 ### DSA and related schemes.
 877
 878 class _tmp:
 879   def __repr__(me): return '%s(G = %r, p = %r, hash = %r)' % \
 880         (_clsname(me), me.G, me.p, me.hash)
 881   def _repr_pretty_(me, pp, cyclep):
 882     ind = _pp_bgroup_tyname(pp, me)
 883     if cyclep:
 884       pp.text('...')
 885     else:
 886       _pp_kv(pp, 'G', me.G); pp.text(','); pp.breakable()
 887       _pp_kv(pp, 'p', me.p); pp.text(','); pp.breakable()
 888       _pp_kv(pp, 'hash', me.hash)
 889     pp.end_group(ind, ')')
 890 _augment(DSAPub, _tmp)
 891 _augment(KCDSAPub, _tmp)
 892
 893 class _tmp:
 894   def __repr__(me): return '%s(G = %r, u = %s, p = %r, hash = %r)' % \
 895       (_clsname(me), me.G, _repr_secret(me.u), me.p, me.hash)
 896   def _repr_pretty_(me, pp, cyclep):
 897     ind = _pp_bgroup_tyname(pp, me)
 898     if cyclep:
 899       pp.text('...')
 900     else:
 901       _pp_kv(pp, 'G', me.G); pp.text(','); pp.breakable()
 902       _pp_kv(pp, 'u', me.u, True); pp.text(','); pp.breakable()
 903       _pp_kv(pp, 'p', me.p); pp.text(','); pp.breakable()
 904       _pp_kv(pp, 'hash', me.hash)
 905     pp.end_group(ind, ')')
 906 _augment(DSAPriv, _tmp)
 907 _augment(KCDSAPriv, _tmp)
 908
 909 ###--------------------------------------------------------------------------
 910 ### Bernstein's elliptic curve crypto and related schemes.
 911
 912 X25519_BASE = MP(9).storel(32)
 913 X448_BASE = MP(5).storel(56)
 914
 915 Z128 = ByteString.zero(16)
 916
 917 class _BasePub (object):
 918   def __init__(me, pub, *args, **kw):
 919     if not me._PUBSZ.check(len(pub)): raise ValueError, 'bad public key'
 920     super(_BasePub, me).__init__(*args, **kw)
 921     me.pub = pub
 922   def __repr__(me): return '%s(pub = %r)' % (_clsname(me), me.pub)
 923   def _pp(me, pp): _pp_kv(pp, 'pub', me.pub)
 924   def _repr_pretty_(me, pp, cyclep):
 925     ind = _pp_bgroup_tyname(pp, me)
 926     if cyclep: pp.text('...')
 927     else: me._pp(pp)
 928     pp.end_group(ind, ')')
 929
 930 class _BasePriv (object):
 931   def __init__(me, priv, pub = None, *args, **kw):
 932     if not me._KEYSZ.check(len(priv)): raise ValueError, 'bad private key'
 933     if pub is None: pub = me._pubkey(priv)
 934     super(_BasePriv, me).__init__(pub = pub, *args, **kw)
 935     me.priv = priv
 936   @classmethod
 937   def generate(cls, rng = rand):
 938     return cls(rng.block(cls._KEYSZ.default))
 939   def __repr__(me):
 940     return '%s(priv = %d, pub = %r)' % \
 941         (_clsname(me), _repr_secret(me.priv), me.pub)
 942   def _pp(me, pp):
 943     _pp_kv(pp, 'priv', me.priv, secretp = True); pp.text(','); pp.breakable()
 944     super(_BasePriv, me)._pp(pp)
 945
 946 class _XDHPub (_BasePub):  pass
 947
 948 class _XDHPriv (_BasePriv):
 949   def _pubkey(me, priv): return me._op(priv, me._BASE)
 950   def agree(me, you): return me._op(me.priv, you.pub)
 951   def boxkey(me, recip): return me._hashkey(me.agree(recip))
 952   def box(me, recip, n, m): return secret_box(me.boxkey(recip), n, m)
 953   def unbox(me, recip, n, c): return secret_unbox(me.boxkey(recip), n, c)
 954
 955 class X25519Pub (_XDHPub):
 956   _PUBSZ = KeySZSet(X25519_PUBSZ)
 957   _BASE = X25519_BASE
 958
 959 class X25519Priv (_XDHPriv, X25519Pub):
 960   _KEYSZ = KeySZSet(X25519_KEYSZ)
 961   def _op(me, k, X): return x25519(k, X)
 962   def _hashkey(me, z): return hsalsa20_prf(z, Z128)
 963
 964 class X448Pub (_XDHPub):
 965   _PUBSZ = KeySZSet(X448_PUBSZ)
 966   _BASE = X448_BASE
 967
 968 class X448Priv (_XDHPriv, X448Pub):
 969   _KEYSZ = KeySZSet(X448_KEYSZ)
 970   def _op(me, k, X): return x448(k, X)
 971   def _hashkey(me, z): return Shake256().hash(z).done(salsa20.keysz.default)
 972
 973 class _EdDSAPub (_BasePub):
 974   def beginhash(me): return me._HASH()
 975   def endhash(me, h): return h.done()
 976
 977 class _EdDSAPriv (_BasePriv, _EdDSAPub):
 978   pass
 979
 980 class Ed25519Pub (_EdDSAPub):
 981   _PUBSZ = KeySZSet(ED25519_PUBSZ)
 982   _HASH = sha512
 983   def verify(me, msg, sig, **kw):
 984     return ed25519_verify(me.pub, msg, sig, **kw)
 985
 986 class Ed25519Priv (_EdDSAPriv, Ed25519Pub):
 987   _KEYSZ = KeySZAny(ED25519_KEYSZ)
 988   def _pubkey(me, priv): return ed25519_pubkey(priv)
 989   def sign(me, msg, **kw):
 990     return ed25519_sign(me.priv, msg, pub = me.pub, **kw)
 991
 992 class Ed448Pub (_EdDSAPub):
 993   _PUBSZ = KeySZSet(ED448_PUBSZ)
 994   _HASH = shake256
 995   def verify(me, msg, sig, **kw):
 996     return ed448_verify(me.pub, msg, sig, **kw)
 997
 998 class Ed448Priv (_EdDSAPriv, Ed448Pub):
 999   _KEYSZ = KeySZAny(ED448_KEYSZ)
1000   def _pubkey(me, priv): return ed448_pubkey(priv)
1001   def sign(me, msg, **kw):
1002     return ed448_sign(me.priv, msg, pub = me.pub, **kw)
1003
1004 ###--------------------------------------------------------------------------
1005 ### Built-in named curves and prime groups.
1006
1007 class _groupmap (object):
1008   def __init__(me, map, nth):
1009     me.map = map
1010     me.nth = nth
1011     me._n = max(map.values()) + 1
1012     me.i = me._n*[None]
1013   def __repr__(me):
1014     return '{%s}' % ', '.join(['%r: %r' % kv for kv in me.iteritems()])
1015   def _repr_pretty_(me, pp, cyclep):
1016     ind = _pp_bgroup(pp, '{ ')
1017     if cyclep: pp.text('...')
1018     else: _pp_dict(pp, me.iteritems())
1019     pp.end_group(ind, ' }')
1020   def __len__(me):
1021     return me._n
1022   def __contains__(me, k):
1023     return k in me.map
1024   def __getitem__(me, k):
1025     i = me.map[k]
1026     if me.i[i] is None:
1027       me.i[i] = me.nth(i)
1028     return me.i[i]
1029   def __setitem__(me, k, v):
1030     raise TypeError, "immutable object"
1031   def __iter__(me):
1032     return iter(me.map)
1033   def iterkeys(me):
1034     return iter(me.map)
1035   def itervalues(me):
1036     for k in me:
1037       yield me[k]
1038   def iteritems(me):
1039     for k in me:
1040       yield k, me[k]
1041   def keys(me):
1042     return [k for k in me]
1043   def values(me):
1044     return [me[k] for k in me]
1045   def items(me):
1046     return [(k, me[k]) for k in me]
1047 eccurves = _groupmap(_base._eccurves, ECInfo._curven)
1048 primegroups = _groupmap(_base._pgroups, DHInfo._groupn)
1049 bingroups = _groupmap(_base._bingroups, BinDHInfo._groupn)
1050
1051 ###--------------------------------------------------------------------------
1052 ### Prime number generation.
1053
1054 class PrimeGenEventHandler (object):
1055   def pg_begin(me, ev):
1056     return me.pg_try(ev)
1057   def pg_done(me, ev):
1058     return PGEN_DONE
1059   def pg_abort(me, ev):
1060     return PGEN_TRY
1061   def pg_fail(me, ev):
1062     return PGEN_TRY
1063   def pg_pass(me, ev):
1064     return PGEN_TRY
1065
1066 class SophieGermainStepJump (object):
1067   def pg_begin(me, ev):
1068     me.lf = PrimeFilter(ev.x)
1069     me.hf = me.lf.muladd(2, 1)
1070     return me.cont(ev)
1071   def pg_try(me, ev):
1072     me.step()
1073     return me.cont(ev)
1074   def cont(me, ev):
1075     while me.lf.status == PGEN_FAIL or me.hf.status == PGEN_FAIL:
1076       me.step()
1077     if me.lf.status == PGEN_ABORT or me.hf.status == PGEN_ABORT:
1078       return PGEN_ABORT
1079     ev.x = me.lf.x
1080     if me.lf.status == PGEN_DONE and me.hf.status == PGEN_DONE:
1081       return PGEN_DONE
1082     return PGEN_TRY
1083   def pg_done(me, ev):
1084     del me.lf
1085     del me.hf
1086
1087 class SophieGermainStepper (SophieGermainStepJump):
1088   def __init__(me, step):
1089     me.lstep = step;
1090     me.hstep = 2 * step
1091   def step(me):
1092     me.lf.step(me.lstep)
1093     me.hf.step(me.hstep)
1094
1095 class SophieGermainJumper (SophieGermainStepJump):
1096   def __init__(me, jump):
1097     me.ljump = PrimeFilter(jump);
1098     me.hjump = me.ljump.muladd(2, 0)
1099   def step(me):
1100     me.lf.jump(me.ljump)
1101     me.hf.jump(me.hjump)
1102   def pg_done(me, ev):
1103     del me.ljump
1104     del me.hjump
1105     SophieGermainStepJump.pg_done(me, ev)
1106
1107 class SophieGermainTester (object):
1108   def __init__(me):
1109     pass
1110   def pg_begin(me, ev):
1111     me.lr = RabinMiller(ev.x)
1112     me.hr = RabinMiller(2 * ev.x + 1)
1113   def pg_try(me, ev):
1114     lst = me.lr.test(ev.rng.range(me.lr.x))
1115     if lst != PGEN_PASS and lst != PGEN_DONE:
1116       return lst
1117     rst = me.hr.test(ev.rng.range(me.hr.x))
1118     if rst != PGEN_PASS and rst != PGEN_DONE:
1119       return rst
1120     if lst == PGEN_DONE and rst == PGEN_DONE:
1121       return PGEN_DONE
1122     return PGEN_PASS
1123   def pg_done(me, ev):
1124     del me.lr
1125     del me.hr
1126
1127 class PrimitiveStepper (PrimeGenEventHandler):
1128   def __init__(me):
1129     pass
1130   def pg_try(me, ev):
1131     ev.x = me.i.next()
1132     return PGEN_TRY
1133   def pg_begin(me, ev):
1134     me.i = iter(smallprimes)
1135     return me.pg_try(ev)
1136
1137 class PrimitiveTester (PrimeGenEventHandler):
1138   def __init__(me, mod, hh = [], exp = None):
1139     me.mod = MPMont(mod)
1140     me.exp = exp
1141     me.hh = hh
1142   def pg_try(me, ev):
1143     x = ev.x
1144     if me.exp is not None:
1145       x = me.mod.exp(x, me.exp)
1146       if x == 1: return PGEN_FAIL
1147     for h in me.hh:
1148       if me.mod.exp(x, h) == 1: return PGEN_FAIL
1149     ev.x = x
1150     return PGEN_DONE
1151
1152 class SimulStepper (PrimeGenEventHandler):
1153   def __init__(me, mul = 2, add = 1, step = 2):
1154     me.step = step
1155     me.mul = mul
1156     me.add = add
1157   def _stepfn(me, step):
1158     if step <= 0:
1159       raise ValueError, 'step must be positive'
1160     if step <= MPW_MAX:
1161       return lambda f: f.step(step)
1162     j = PrimeFilter(step)
1163     return lambda f: f.jump(j)
1164   def pg_begin(me, ev):
1165     x = ev.x
1166     me.lf = PrimeFilter(x)
1167     me.hf = PrimeFilter(x * me.mul + me.add)
1168     me.lstep = me._stepfn(me.step)
1169     me.hstep = me._stepfn(me.step * me.mul)
1170     SimulStepper._cont(me, ev)
1171   def pg_try(me, ev):
1172     me._step()
1173     me._cont(ev)
1174   def _step(me):
1175     me.lstep(me.lf)
1176     me.hstep(me.hf)
1177   def _cont(me, ev):
1178     while me.lf.status == PGEN_FAIL or me.hf.status == PGEN_FAIL:
1179       me._step()
1180     if me.lf.status == PGEN_ABORT or me.hf.status == PGEN_ABORT:
1181       return PGEN_ABORT
1182     ev.x = me.lf.x
1183     if me.lf.status == PGEN_DONE and me.hf.status == PGEN_DONE:
1184       return PGEN_DONE
1185     return PGEN_TRY
1186   def pg_done(me, ev):
1187     del me.lf
1188     del me.hf
1189     del me.lstep
1190     del me.hstep
1191
1192 class SimulTester (PrimeGenEventHandler):
1193   def __init__(me, mul = 2, add = 1):
1194     me.mul = mul
1195     me.add = add
1196   def pg_begin(me, ev):
1197     x = ev.x
1198     me.lr = RabinMiller(x)
1199     me.hr = RabinMiller(x * me.mul + me.add)
1200   def pg_try(me, ev):
1201     lst = me.lr.test(ev.rng.range(me.lr.x))
1202     if lst != PGEN_PASS and lst != PGEN_DONE:
1203       return lst
1204     rst = me.hr.test(ev.rng.range(me.hr.x))
1205     if rst != PGEN_PASS and rst != PGEN_DONE:
1206       return rst
1207     if lst == PGEN_DONE and rst == PGEN_DONE:
1208       return PGEN_DONE
1209     return PGEN_PASS
1210   def pg_done(me, ev):
1211     del me.lr
1212     del me.hr
1213
1214 def sgprime(start, step = 2, name = 'p', event = pgen_nullev, nsteps = 0):
1215   start = MP(start)
1216   return pgen(start, name, SimulStepper(step = step), SimulTester(), event,
1217               nsteps, RabinMiller.iters(start.nbits))
1218
1219 def findprimitive(mod, hh = [], exp = None, name = 'g', event = pgen_nullev):
1220   return pgen(0, name, PrimitiveStepper(), PrimitiveTester(mod, hh, exp),
1221               event, 0, 1)
1222
1223 def kcdsaprime(pbits, qbits, rng = rand,
1224                event = pgen_nullev, name = 'p', nsteps = 0):
1225   hbits = pbits - qbits
1226   h = pgen(rng.mp(hbits, 1), name + ' [h]',
1227            PrimeGenStepper(2), PrimeGenTester(),
1228            event, nsteps, RabinMiller.iters(hbits))
1229   q = pgen(rng.mp(qbits, 1), name, SimulStepper(2 * h, 1, 2),
1230            SimulTester(2 * h, 1), event, nsteps, RabinMiller.iters(qbits))
1231   p = 2 * q * h + 1
1232   return p, q, h
1233
1234 #----- That's all, folks ----------------------------------------------------