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 if _sys.version_info >= (3,): from . import _base
  59 else: import _base
  60
  61 if _odlflags >= 0:
  62   _sys.setdlopenflags(_odlflags)
  63
  64 del _dlflags, _odlflags
  65
  66 ###--------------------------------------------------------------------------
  67 ### Basic stuff.
  68
  69 ## For the benefit of the default keyreporter, we need the program name.
  70 _base._ego(_sys.argv[0])
  71
  72 ## Register our module.
  73 _base._set_home_module(_sys.modules[__name__])
  74 def default_lostexchook(why, ty, val, tb):
  75   """`catacomb.lostexchook(WHY, TY, VAL, TB)' reports lost exceptions."""
  76   _sys.stderr.write("\n\n!!! LOST EXCEPTION: %s\n" % why)
  77   _sys.excepthook(ty, val, tb)
  78   _sys.stderr.write("\n")
  79 lostexchook = default_lostexchook
  80
  81 ## Text/binary conversions.
  82 if _sys.version_info >= (3,):
  83   def _bin(s): return s.encode('iso8859-1')
  84 else:
  85   def _bin(s): return s
  86
  87 ## Iterating over dictionaries.
  88 if _sys.version_info >= (3,):
  89   def _iteritems(dict): return dict.items()
  90   def _itervalues(dict): return dict.values()
  91 else:
  92   def _iteritems(dict): return dict.iteritems()
  93   def _itervalues(dict): return dict.itervalues()
  94
  95 ## The built-in bignum type.
  96 try: long
  97 except NameError: _long = int
  98 else: _long = long
  99
 100 ## How to fix a name back into the right identifier.  Alas, the rules are not
 101 ## consistent.
 102 def _fixname(name):
 103
 104   ## Hyphens consistently become underscores.
 105   name = name.replace('-', '_')
 106
 107   ## But slashes might become underscores or just vanish.
 108   if name.startswith('salsa20'): name = name.replace('/', '')
 109   else: name = name.replace('/', '_')
 110
 111   ## Done.
 112   return name
 113
 114 ## Initialize the module.  Drag in the static methods of the various
 115 ## classes; create names for the various known crypto algorithms.
 116 def _init():
 117   d = globals()
 118   b = _base.__dict__;
 119   for i in b:
 120     if i[0] != '_':
 121       d[i] = b[i];
 122   for i in [gcciphers, gcaeads, gchashes, gcmacs, gcprps]:
 123     for c in _itervalues(i):
 124       d[_fixname(c.name)] = c
 125   for c in _itervalues(gccrands):
 126     d[_fixname(c.name + 'rand')] = c
 127 _init()
 128
 129 ## A handy function for our work: add the methods of a named class to an
 130 ## existing class.  This is how we write the Python-implemented parts of our
 131 ## mostly-C types.
 132 def _augment(c, cc):
 133   for i in cc.__dict__:
 134     a = cc.__dict__[i]
 135     if type(a) is _types.MethodType:
 136       a = a.im_func
 137     elif type(a) not in (_types.FunctionType, staticmethod, classmethod):
 138       continue
 139     setattr(c, i, a)
 140
 141 ## Parsing functions tend to return the object parsed and the remainder of
 142 ## the input.  This checks that the remainder is input and, if so, returns
 143 ## just the object.
 144 def _checkend(r):
 145   x, rest = r
 146   if rest != '':
 147     raise SyntaxError('junk at end of string')
 148   return x
 149
 150 ## Some pretty-printing utilities.
 151 PRINT_SECRETS = False
 152 def _clsname(me): return type(me).__name__
 153 def _repr_secret(thing, secretp = True):
 154   if not secretp or PRINT_SECRETS: return repr(thing)
 155   else: return '#<SECRET>'
 156 def _pp_str(me, pp, cyclep): pp.text(cyclep and '...' or str(me))
 157 def _pp_secret(pp, thing, secretp = True):
 158   if not secretp or PRINT_SECRETS: pp.pretty(thing)
 159   else: pp.text('#<SECRET>')
 160 def _pp_bgroup(pp, text):
 161   ind = len(text)
 162   pp.begin_group(ind, text)
 163   return ind
 164 def _pp_bgroup_tyname(pp, obj, open = '('):
 165   return _pp_bgroup(pp, _clsname(obj) + open)
 166 def _pp_kv(pp, k, v, secretp = False):
 167   ind = _pp_bgroup(pp, k + ' = ')
 168   _pp_secret(pp, v, secretp)
 169   pp.end_group(ind, '')
 170 def _pp_commas(pp, printfn, items):
 171   firstp = True
 172   for i in items:
 173     if firstp: firstp = False
 174     else: pp.text(','); pp.breakable()
 175     printfn(i)
 176 def _pp_dict(pp, items):
 177   def p(kv):
 178     k, v = kv
 179     pp.begin_group(0)
 180     pp.pretty(k)
 181     pp.text(':')
 182     pp.begin_group(2)
 183     pp.breakable()
 184     pp.pretty(v)
 185     pp.end_group(2)
 186     pp.end_group(0)
 187   _pp_commas(pp, p, items)
 188
 189 ###--------------------------------------------------------------------------
 190 ### Mappings.
 191
 192 if _sys.version_info >= (3,):
 193   class _tmp:
 194     def __str__(me): return '%s(%r)' % (type(me).__name__, list(me))
 195     __repr__ = __str__
 196     def _repr_pretty_(me, pp, cyclep):
 197       ind = _pp_bgroup_tyname(pp, me, '([')
 198       _pp_commas(pp, pp.pretty, me)
 199       pp.end_group(ind, '])')
 200   _augment(_base._KeyView, _tmp)
 201   _augment(_base._ValueView, _tmp)
 202   _augment(_base._ItemView, _tmp)
 203
 204 ###--------------------------------------------------------------------------
 205 ### Bytestrings.
 206
 207 class _tmp:
 208   def fromhex(x):
 209     return ByteString(_unhexify(x))
 210   fromhex = staticmethod(fromhex)
 211   if _sys.version_info >= (3,):
 212     def hex(me): return _hexify(me).decode()
 213   else:
 214     def hex(me): return _hexify(me)
 215     __hex__ = hex
 216   def __repr__(me):
 217     return 'bytes(%r)' % me.hex()
 218 _augment(ByteString, _tmp)
 219 ByteString.__hash__ = str.__hash__
 220 bytes = ByteString.fromhex
 221
 222 ###--------------------------------------------------------------------------
 223 ### Symmetric encryption.
 224
 225 class _tmp:
 226   def encrypt(me, n, m, tsz = None, h = ByteString.zero(0)):
 227     if tsz is None: tsz = me.__class__.tagsz.default
 228     e = me.enc(n, len(h), len(m), tsz)
 229     if not len(h): a = None
 230     else: a = e.aad().hash(h)
 231     c0 = e.encrypt(m)
 232     c1, t = e.done(aad = a)
 233     return c0 + c1, t
 234   def decrypt(me, n, c, t, h = ByteString.zero(0)):
 235     d = me.dec(n, len(h), len(c), len(t))
 236     if not len(h): a = None
 237     else: a = d.aad().hash(h)
 238     m = d.decrypt(c)
 239     m += d.done(t, aad = a)
 240     return m
 241 _augment(GAEKey, _tmp)
 242
 243 ###--------------------------------------------------------------------------
 244 ### Hashing.
 245
 246 class _tmp:
 247   def check(me, h):
 248     hh = me.done()
 249     return ctstreq(h, hh)
 250 _augment(GHash, _tmp)
 251 _augment(Poly1305Hash, _tmp)
 252
 253 class _tmp:
 254   def check(me, h):
 255     return ctstreq(h, me.done(len(h)))
 256 _augment(Shake, _tmp)
 257
 258 KMAC128.keysz = KeySZAny(16); KMAC128.tagsz = 16
 259 KMAC256.keysz = KeySZAny(32); KMAC256.tagsz = 32
 260
 261 ###--------------------------------------------------------------------------
 262 ### NaCl `secretbox'.
 263
 264 def secret_box(k, n, m):
 265   y, t = salsa20_naclbox(k).encrypt(n, m)
 266   return t + y
 267
 268 def secret_unbox(k, n, c):
 269   tsz = poly1305.tagsz
 270   return salsa20_naclbox(k).decrypt(n, c[tsz:], c[0:tsz])
 271
 272 ###--------------------------------------------------------------------------
 273 ### Multiprecision integers and binary polynomials.
 274
 275 class BaseRat (object):
 276   """Base class implementing fields of fractions over Euclidean domains."""
 277   def __new__(cls, a, b):
 278     a, b = cls.RING(a), cls.RING(b)
 279     q, r = divmod(a, b)
 280     if r == cls.ZERO: return q
 281     g = b.gcd(r)
 282     me = super(BaseRat, cls).__new__(cls)
 283     me._n = a//g
 284     me._d = b//g
 285     return me
 286   @property
 287   def numer(me): return me._n
 288   @property
 289   def denom(me): return me._d
 290   def __str__(me): return '%s/%s' % (me._n, me._d)
 291   def __repr__(me): return '%s(%s, %s)' % (_clsname(me), me._n, me._d)
 292   _repr_pretty_ = _pp_str
 293
 294   def _split_rat(me, x):
 295     if isinstance(x, me.__class__): return x._n, x._d
 296     else: return x, me.ONE
 297   def __add__(me, you):
 298     n, d = me._split_rat(you)
 299     return type(me)(me._n*d + n*me._d, d*me._d)
 300   __radd__ = __add__
 301   def __sub__(me, you):
 302     n, d = me._split_rat(you)
 303     return type(me)(me._n*d - n*me._d, d*me._d)
 304   def __rsub__(me, you):
 305     n, d = me._split_rat(you)
 306     return type(me)(n*me._d - me._n*d, d*me._d)
 307   def __mul__(me, you):
 308     n, d = me._split_rat(you)
 309     return type(me)(me._n*n, me._d*d)
 310   __rmul__ = __mul__
 311   def __truediv__(me, you):
 312     n, d = me._split_rat(you)
 313     return type(me)(me._n*d, me._d*n)
 314   def __rtruediv__(me, you):
 315     n, d = me._split_rat(you)
 316     return type(me)(me._d*n, me._n*d)
 317   if _sys.version_info < (3,):
 318     __div__ = __truediv__
 319     __rdiv__ = __rtruediv__
 320   def _order(me, you, op):
 321     n, d = me._split_rat(you)
 322     return op(me._n*d, n*me._d)
 323   def __eq__(me, you): return me._order(you, lambda x, y: x == y)
 324   def __ne__(me, you): return me._order(you, lambda x, y: x != y)
 325   def __le__(me, you): return me._order(you, lambda x, y: x <= y)
 326   def __lt__(me, you): return me._order(you, lambda x, y: x <  y)
 327   def __gt__(me, you): return me._order(you, lambda x, y: x >  y)
 328   def __ge__(me, you): return me._order(you, lambda x, y: x >= y)
 329
 330 class IntRat (BaseRat):
 331   RING = MP
 332   ZERO, ONE = MP(0), MP(1)
 333   def __new__(cls, a, b):
 334     if isinstance(a, float) or isinstance(b, float): return a/b
 335     return super(IntRat, cls).__new__(cls, a, b)
 336   def __float__(me): return float(me._n)/float(me._d)
 337
 338 class GFRat (BaseRat):
 339   RING = GF
 340   ZERO, ONE = GF(0), GF(1)
 341
 342 class _tmp:
 343   def negp(x): return x < 0
 344   def posp(x): return x > 0
 345   def zerop(x): return x == 0
 346   def oddp(x): return x.testbit(0)
 347   def evenp(x): return not x.testbit(0)
 348   def mont(x): return MPMont(x)
 349   def barrett(x): return MPBarrett(x)
 350   def reduce(x): return MPReduce(x)
 351   def __truediv__(me, you):
 352     if isinstance(you, float): return _long(me)/you
 353     else: return IntRat(me, you)
 354   def __rtruediv__(me, you):
 355     if isinstance(you, float): return you/_long(me)
 356     else: return IntRat(you, me)
 357   if _sys.version_info < (3,):
 358     __div__ = __truediv__
 359     __rdiv__ = __rtruediv__
 360   _repr_pretty_ = _pp_str
 361 _augment(MP, _tmp)
 362
 363 class _tmp:
 364   def zerop(x): return x == 0
 365   def reduce(x): return GFReduce(x)
 366   def trace(x, y): return x.reduce().trace(y)
 367   def halftrace(x, y): return x.reduce().halftrace(y)
 368   def modsqrt(x, y): return x.reduce().sqrt(y)
 369   def quadsolve(x, y): return x.reduce().quadsolve(y)
 370   def __truediv__(me, you): return GFRat(me, you)
 371   def __rtruediv__(me, you): return GFRat(you, me)
 372   if _sys.version_info < (3,):
 373     __div__ = __truediv__
 374     __rdiv__ = __rtruediv__
 375   _repr_pretty_ = _pp_str
 376 _augment(GF, _tmp)
 377
 378 class _tmp:
 379   def product(*arg):
 380     'product(ITERABLE) or product(I, ...) -> PRODUCT'
 381     return MPMul(*arg).done()
 382   product = staticmethod(product)
 383 _augment(MPMul, _tmp)
 384
 385 ###--------------------------------------------------------------------------
 386 ### Abstract fields.
 387
 388 class _tmp:
 389   def fromstring(str): return _checkend(Field.parse(str))
 390   fromstring = staticmethod(fromstring)
 391 _augment(Field, _tmp)
 392
 393 class _tmp:
 394   def __repr__(me): return '%s(%s)' % (_clsname(me), me.p)
 395   def __hash__(me): return 0x114401de ^ hash(me.p)
 396   def _repr_pretty_(me, pp, cyclep):
 397     ind = _pp_bgroup_tyname(pp, me)
 398     if cyclep: pp.text('...')
 399     else: pp.pretty(me.p)
 400     pp.end_group(ind, ')')
 401   def ec(me, a, b): return ECPrimeProjCurve(me, a, b)
 402 _augment(PrimeField, _tmp)
 403
 404 class _tmp:
 405   def __repr__(me): return '%s(%#x)' % (_clsname(me), me.p)
 406   def ec(me, a, b): return ECBinProjCurve(me, a, b)
 407   def _repr_pretty_(me, pp, cyclep):
 408     ind = _pp_bgroup_tyname(pp, me)
 409     if cyclep: pp.text('...')
 410     else: pp.text('%#x' % me.p)
 411     pp.end_group(ind, ')')
 412 _augment(BinField, _tmp)
 413
 414 class _tmp:
 415   def __hash__(me): return 0x23e4701c ^ hash(me.p)
 416 _augment(BinPolyField, _tmp)
 417
 418 class _tmp:
 419   def __hash__(me):
 420     h = 0x9a7d6240
 421     h ^=   hash(me.p)
 422     h ^= 2*hash(me.beta) & 0xffffffff
 423     return h
 424 _augment(BinNormField, _tmp)
 425
 426 class _tmp:
 427   def __str__(me): return str(me.value)
 428   def __repr__(me): return '%s(%s)' % (repr(me.field), repr(me.value))
 429   _repr_pretty_ = _pp_str
 430 _augment(FE, _tmp)
 431
 432 ###--------------------------------------------------------------------------
 433 ### Elliptic curves.
 434
 435 class _tmp:
 436   def __repr__(me):
 437     return '%s(%r, %s, %s)' % (_clsname(me), me.field, me.a, me.b)
 438   def _repr_pretty_(me, pp, cyclep):
 439     ind = _pp_bgroup_tyname(pp, me)
 440     if cyclep:
 441       pp.text('...')
 442     else:
 443       pp.pretty(me.field); pp.text(','); pp.breakable()
 444       pp.pretty(me.a); pp.text(','); pp.breakable()
 445       pp.pretty(me.b)
 446     pp.end_group(ind, ')')
 447   def frombuf(me, s):
 448     return ecpt.frombuf(me, s)
 449   def fromraw(me, s):
 450     return ecpt.fromraw(me, s)
 451   def pt(me, *args):
 452     return me(*args)
 453 _augment(ECCurve, _tmp)
 454
 455 class _tmp:
 456   def __hash__(me):
 457     h = 0x6751d341
 458     h ^=   hash(me.field)
 459     h ^= 2*hash(me.a) ^ 0xffffffff
 460     h ^= 5*hash(me.b) ^ 0xffffffff
 461     return h
 462 _augment(ECPrimeCurve, _tmp)
 463
 464 class _tmp:
 465   def __hash__(me):
 466     h = 0x2ac203c5
 467     h ^=   hash(me.field)
 468     h ^= 2*hash(me.a) ^ 0xffffffff
 469     h ^= 5*hash(me.b) ^ 0xffffffff
 470     return h
 471 _augment(ECBinCurve, _tmp)
 472
 473 class _tmp:
 474   def __repr__(me):
 475     if not me: return '%s()' % _clsname(me)
 476     return '%s(%s, %s)' % (_clsname(me), me.ix, me.iy)
 477   def __str__(me):
 478     if not me: return 'inf'
 479     return '(%s, %s)' % (me.ix, me.iy)
 480   def _repr_pretty_(me, pp, cyclep):
 481     if cyclep:
 482       pp.text('...')
 483     elif not me:
 484       pp.text('inf')
 485     else:
 486       ind = _pp_bgroup(pp, '(')
 487       pp.pretty(me.ix); pp.text(','); pp.breakable()
 488       pp.pretty(me.iy)
 489       pp.end_group(ind, ')')
 490 _augment(ECPt, _tmp)
 491
 492 class _tmp:
 493   def __repr__(me):
 494     return '%s(curve = %r, G = %r, r = %s, h = %s)' % \
 495            (_clsname(me), me.curve, me.G, me.r, me.h)
 496   def _repr_pretty_(me, pp, cyclep):
 497     ind = _pp_bgroup_tyname(pp, me)
 498     if cyclep:
 499       pp.text('...')
 500     else:
 501       _pp_kv(pp, 'curve', me.curve); pp.text(','); pp.breakable()
 502       _pp_kv(pp, 'G', me.G); pp.text(','); pp.breakable()
 503       _pp_kv(pp, 'r', me.r); pp.text(','); pp.breakable()
 504       _pp_kv(pp, 'h', me.h)
 505     pp.end_group(ind, ')')
 506   def __hash__(me):
 507     h = 0x9bedb8de
 508     h ^=   hash(me.curve)
 509     h ^= 2*hash(me.G) & 0xffffffff
 510     return h
 511   def group(me):
 512     return ECGroup(me)
 513 _augment(ECInfo, _tmp)
 514
 515 class _tmp:
 516   def __repr__(me):
 517     if not me: return '%r()' % (me.curve)
 518     return '%r(%s, %s)' % (me.curve, me.x, me.y)
 519   def __str__(me):
 520     if not me: return 'inf'
 521     return '(%s, %s)' % (me.x, me.y)
 522   def _repr_pretty_(me, pp, cyclep):
 523     if cyclep:
 524       pp.text('...')
 525     elif not me:
 526       pp.text('inf')
 527     else:
 528       ind = _pp_bgroup(pp, '(')
 529       pp.pretty(me.x); pp.text(','); pp.breakable()
 530       pp.pretty(me.y)
 531       pp.end_group(ind, ')')
 532 _augment(ECPtCurve, _tmp)
 533
 534 ###--------------------------------------------------------------------------
 535 ### Key sizes.
 536
 537 class _tmp:
 538   def __repr__(me): return '%s(%d)' % (_clsname(me), me.default)
 539   def check(me, sz): return True
 540   def best(me, sz): return sz
 541   def pad(me, sz): return sz
 542 _augment(KeySZAny, _tmp)
 543
 544 class _tmp:
 545   def __repr__(me):
 546     return '%s(%d, %d, %d, %d)' % \
 547            (_clsname(me), me.default, me.min, me.max, me.mod)
 548   def _repr_pretty_(me, pp, cyclep):
 549     ind = _pp_bgroup_tyname(pp, me)
 550     if cyclep:
 551       pp.text('...')
 552     else:
 553       pp.pretty(me.default); pp.text(','); pp.breakable()
 554       pp.pretty(me.min); pp.text(','); pp.breakable()
 555       pp.pretty(me.max); pp.text(','); pp.breakable()
 556       pp.pretty(me.mod)
 557     pp.end_group(ind, ')')
 558   def check(me, sz): return me.min <= sz <= me.max and sz%me.mod == 0
 559   def best(me, sz):
 560     if sz < me.min: raise ValueError('key too small')
 561     elif me.max is not None and sz > me.max: return me.max
 562     else: return sz - sz%me.mod
 563   def pad(me, sz):
 564     if me.max is not None and sz > me.max: raise ValueError('key too large')
 565     elif sz < me.min: return me.min
 566     else: sz += me.mod - 1; return sz - sz%me.mod
 567 _augment(KeySZRange, _tmp)
 568
 569 class _tmp:
 570   def __repr__(me): return '%s(%d, %s)' % (_clsname(me), me.default, me.set)
 571   def _repr_pretty_(me, pp, cyclep):
 572     ind = _pp_bgroup_tyname(pp, me)
 573     if cyclep:
 574       pp.text('...')
 575     else:
 576       pp.pretty(me.default); pp.text(','); pp.breakable()
 577       ind1 = _pp_bgroup(pp, '{')
 578       _pp_commas(pp, pp.pretty, me.set)
 579       pp.end_group(ind1, '}')
 580     pp.end_group(ind, ')')
 581   def check(me, sz): return sz in me.set
 582   def best(me, sz):
 583     found = -1
 584     for i in me.set:
 585       if found < i <= sz: found = i
 586     if found < 0: raise ValueError('key too small')
 587     return found
 588   def pad(me, sz):
 589     found = -1
 590     for i in me.set:
 591       if sz <= i and (found == -1 or i < found): found = i
 592     if found < 0: raise ValueError('key too large')
 593     return found
 594 _augment(KeySZSet, _tmp)
 595
 596 ###--------------------------------------------------------------------------
 597 ### Key data objects.
 598
 599 class _tmp:
 600   def merge(me, file, report = None):
 601     """KF.merge(FILE, [report = <built-in-reporter>])"""
 602     name = file.name
 603     lno = 1
 604     for line in file:
 605       me.mergeline(name, lno, line, report)
 606       lno += 1
 607     return me
 608   def __repr__(me): return '%s(%r)' % (_clsname(me), me.name)
 609 _augment(KeyFile, _tmp)
 610
 611 class _tmp:
 612   def extract(me, file, filter = ''):
 613     """KEY.extract(FILE, [filter = <any>])"""
 614     line = me.extractline(filter)
 615     file.write(line)
 616     return me
 617   def __repr__(me): return '%s(%r)' % (_clsname(me), me.fulltag)
 618 _augment(Key, _tmp)
 619
 620 class _tmp:
 621   def __repr__(me):
 622     return '%s({%s})' % (_clsname(me),
 623                          ', '.join(['%r: %r' % kv for kv in _iteritems(me)()]))
 624   def _repr_pretty_(me, pp, cyclep):
 625     ind = _pp_bgroup_tyname(pp, me)
 626     if cyclep: pp.text('...')
 627     else: _pp_dict(pp, _iteritems(me))
 628     pp.end_group(ind, ')')
 629 _augment(KeyAttributes, _tmp)
 630
 631 class _tmp:
 632   def __repr__(me):
 633     return '%s(%s, %r)' % (_clsname(me),
 634                            _repr_secret(me._guts(),
 635                                         not (me.flags & KF_NONSECRET)),
 636                            me.writeflags(me.flags))
 637   def _repr_pretty_(me, pp, cyclep):
 638     ind = _pp_bgroup_tyname(pp, me)
 639     if cyclep:
 640       pp.text('...')
 641     else:
 642       _pp_secret(pp, me._guts(), not (me.flags & KF_NONSECRET))
 643       pp.text(','); pp.breakable()
 644       pp.pretty(me.writeflags(me.flags))
 645     pp.end_group(ind, ')')
 646   def __hash__(me): return me._HASHBASE ^ hash(me._guts())
 647   def __eq__(me, kd):
 648     return type(me) == type(kd) and \
 649       me._guts() == kd._guts() and \
 650       me.flags == kd.flags
 651   def __ne__(me, kd):
 652     return not me == kd
 653 _augment(KeyData, _tmp)
 654
 655 class _tmp:
 656   def _guts(me): return me.bin
 657   def __eq__(me, kd):
 658     return isinstance(kd, KeyDataBinary) and me.bin == kd.bin
 659 _augment(KeyDataBinary, _tmp)
 660 KeyDataBinary._HASHBASE = 0x961755c3
 661
 662 class _tmp:
 663   def _guts(me): return me.ct
 664 _augment(KeyDataEncrypted, _tmp)
 665 KeyDataEncrypted._HASHBASE = 0xffe000d4
 666
 667 class _tmp:
 668   def _guts(me): return me.mp
 669 _augment(KeyDataMP, _tmp)
 670 KeyDataMP._HASHBASE = 0x1cb64d69
 671
 672 class _tmp:
 673   def _guts(me): return me.str
 674 _augment(KeyDataString, _tmp)
 675 KeyDataString._HASHBASE = 0x349c33ea
 676
 677 class _tmp:
 678   def _guts(me): return me.ecpt
 679 _augment(KeyDataECPt, _tmp)
 680 KeyDataECPt._HASHBASE = 0x2509718b
 681
 682 class _tmp:
 683   def __repr__(me):
 684     return '%s({%s})' % (_clsname(me),
 685                          ', '.join(['%r: %r' % kv for kv in _iteritems(me)]))
 686   def _repr_pretty_(me, pp, cyclep):
 687     ind = _pp_bgroup_tyname(pp, me, '({ ')
 688     if cyclep: pp.text('...')
 689     else: _pp_dict(pp, _iteritems(me))
 690     pp.end_group(ind, ' })')
 691   def __hash__(me):
 692     h = me._HASHBASE
 693     for k, v in _iteritems(me):
 694       h = ((h << 1) ^ 3*hash(k) ^ 5*hash(v))&0xffffffff
 695     return h
 696   def __eq__(me, kd):
 697     if type(me) != type(kd) or me.flags != kd.flags or len(me) != len(kd):
 698       return False
 699     for k, v in _iteritems(me):
 700       try: vv = kd[k]
 701       except KeyError: return False
 702       if v != vv: return False
 703     return True
 704 _augment(KeyDataStructured, _tmp)
 705 KeyDataStructured._HASHBASE = 0x85851b21
 706
 707 ###--------------------------------------------------------------------------
 708 ### Abstract groups.
 709
 710 class _tmp:
 711   def __repr__(me):
 712     return '%s(p = %s, r = %s, g = %s)' % (_clsname(me), me.p, me.r, me.g)
 713   def _repr_pretty_(me, pp, cyclep):
 714     ind = _pp_bgroup_tyname(pp, me)
 715     if cyclep:
 716       pp.text('...')
 717     else:
 718       _pp_kv(pp, 'p', me.p); pp.text(','); pp.breakable()
 719       _pp_kv(pp, 'r', me.r); pp.text(','); pp.breakable()
 720       _pp_kv(pp, 'g', me.g)
 721     pp.end_group(ind, ')')
 722 _augment(FGInfo, _tmp)
 723
 724 class _tmp:
 725   def group(me): return PrimeGroup(me)
 726 _augment(DHInfo, _tmp)
 727
 728 class _tmp:
 729   def group(me): return BinGroup(me)
 730 _augment(BinDHInfo, _tmp)
 731
 732 class _tmp:
 733   def __repr__(me):
 734     return '%s(%r)' % (_clsname(me), me.info)
 735   def _repr_pretty_(me, pp, cyclep):
 736     ind = _pp_bgroup_tyname(pp, me)
 737     if cyclep: pp.text('...')
 738     else: pp.pretty(me.info)
 739     pp.end_group(ind, ')')
 740 _augment(Group, _tmp)
 741
 742 class _tmp:
 743   def __hash__(me):
 744     info = me.info
 745     h = 0xbce3cfe6
 746     h ^=   hash(info.p)
 747     h ^= 2*hash(info.r) & 0xffffffff
 748     h ^= 5*hash(info.g) & 0xffffffff
 749     return h
 750   def _get_geval(me, x): return MP(x)
 751 _augment(PrimeGroup, _tmp)
 752
 753 class _tmp:
 754   def __hash__(me):
 755     info = me.info
 756     h = 0x80695949
 757     h ^=   hash(info.p)
 758     h ^= 2*hash(info.r) & 0xffffffff
 759     h ^= 5*hash(info.g) & 0xffffffff
 760     return h
 761   def _get_geval(me, x): return GF(x)
 762 _augment(BinGroup, _tmp)
 763
 764 class _tmp:
 765   def __hash__(me): return 0x0ec23dab ^ hash(me.info)
 766   def _get_geval(me, x): return x.toec()
 767 _augment(ECGroup, _tmp)
 768
 769 class _tmp:
 770   def __repr__(me):
 771     return '%r(%r)' % (me.group, str(me))
 772   def _repr_pretty_(me, pp, cyclep):
 773     pp.pretty(type(me)._get_geval(me))
 774 _augment(GE, _tmp)
 775
 776 ###--------------------------------------------------------------------------
 777 ### RSA encoding techniques.
 778
 779 class PKCS1Crypt (object):
 780   def __init__(me, ep = _bin(''), rng = rand):
 781     me.ep = ep
 782     me.rng = rng
 783   def encode(me, msg, nbits):
 784     return _base._p1crypt_encode(msg, nbits, me.ep, me.rng)
 785   def decode(me, ct, nbits):
 786     return _base._p1crypt_decode(ct, nbits, me.ep, me.rng)
 787
 788 class PKCS1Sig (object):
 789   def __init__(me, ep = _bin(''), rng = rand):
 790     me.ep = ep
 791     me.rng = rng
 792   def encode(me, msg, nbits):
 793     return _base._p1sig_encode(msg, nbits, me.ep, me.rng)
 794   def decode(me, msg, sig, nbits):
 795     return _base._p1sig_decode(msg, sig, nbits, me.ep, me.rng)
 796
 797 class OAEP (object):
 798   def __init__(me, mgf = sha_mgf, hash = sha, ep = _bin(''), rng = rand):
 799     me.mgf = mgf
 800     me.hash = hash
 801     me.ep = ep
 802     me.rng = rng
 803   def encode(me, msg, nbits):
 804     return _base._oaep_encode(msg, nbits, me.mgf, me.hash, me.ep, me.rng)
 805   def decode(me, ct, nbits):
 806     return _base._oaep_decode(ct, nbits, me.mgf, me.hash, me.ep, me.rng)
 807
 808 class PSS (object):
 809   def __init__(me, mgf = sha_mgf, hash = sha, saltsz = None, rng = rand):
 810     me.mgf = mgf
 811     me.hash = hash
 812     if saltsz is None:
 813       saltsz = hash.hashsz
 814     me.saltsz = saltsz
 815     me.rng = rng
 816   def encode(me, msg, nbits):
 817     return _base._pss_encode(msg, nbits, me.mgf, me.hash, me.saltsz, me.rng)
 818   def decode(me, msg, sig, nbits):
 819     return _base._pss_decode(msg, sig, nbits,
 820                              me.mgf, me.hash, me.saltsz, me.rng)
 821
 822 class _tmp:
 823   def encrypt(me, msg, enc):
 824     return me.pubop(enc.encode(msg, me.n.nbits))
 825   def verify(me, msg, sig, enc):
 826     if msg is None: return enc.decode(msg, me.pubop(sig), me.n.nbits)
 827     try:
 828       x = enc.decode(msg, me.pubop(sig), me.n.nbits)
 829       return x is None or x == msg
 830     except ValueError:
 831       return False
 832   def __repr__(me):
 833     return '%s(n = %r, e = %r)' % (_clsname(me), me.n, me.e)
 834   def _repr_pretty_(me, pp, cyclep):
 835     ind = _pp_bgroup_tyname(pp, me)
 836     if cyclep:
 837       pp.text('...')
 838     else:
 839       _pp_kv(pp, 'n', me.n); pp.text(','); pp.breakable()
 840       _pp_kv(pp, 'e', me.e)
 841     pp.end_group(ind, ')')
 842 _augment(RSAPub, _tmp)
 843
 844 class _tmp:
 845   def decrypt(me, ct, enc): return enc.decode(me.privop(ct), me.n.nbits)
 846   def sign(me, msg, enc): return me.privop(enc.encode(msg, me.n.nbits))
 847   def __repr__(me):
 848     return '%s(n = %r, e = %r, d = %s, ' \
 849       'p = %s, q = %s, dp = %s, dq = %s, q_inv = %s)' % \
 850       (_clsname(me), me.n, me.e,
 851        _repr_secret(me.d), _repr_secret(me.p), _repr_secret(me.q),
 852        _repr_secret(me.dp), _repr_secret(me.dq), _repr_secret(me.q_inv))
 853   def _repr_pretty_(me, pp, cyclep):
 854     ind = _pp_bgroup_tyname(pp, me)
 855     if cyclep:
 856       pp.text('...')
 857     else:
 858       _pp_kv(pp, 'n', me.n); pp.text(','); pp.breakable()
 859       _pp_kv(pp, 'e', me.e); pp.text(','); pp.breakable()
 860       _pp_kv(pp, 'd', me.d, secretp = True); pp.text(','); pp.breakable()
 861       _pp_kv(pp, 'p', me.p, secretp = True); pp.text(','); pp.breakable()
 862       _pp_kv(pp, 'q', me.q, secretp = True); pp.text(','); pp.breakable()
 863       _pp_kv(pp, 'dp', me.dp, secretp = True); pp.text(','); pp.breakable()
 864       _pp_kv(pp, 'dq', me.dq, secretp = True); pp.text(','); pp.breakable()
 865       _pp_kv(pp, 'q_inv', me.q_inv, secretp = True)
 866     pp.end_group(ind, ')')
 867 _augment(RSAPriv, _tmp)
 868
 869 ###--------------------------------------------------------------------------
 870 ### DSA and related schemes.
 871
 872 class _tmp:
 873   def __repr__(me): return '%s(G = %r, p = %r, hash = %r)' % \
 874         (_clsname(me), me.G, me.p, me.hash)
 875   def _repr_pretty_(me, pp, cyclep):
 876     ind = _pp_bgroup_tyname(pp, me)
 877     if cyclep:
 878       pp.text('...')
 879     else:
 880       _pp_kv(pp, 'G', me.G); pp.text(','); pp.breakable()
 881       _pp_kv(pp, 'p', me.p); pp.text(','); pp.breakable()
 882       _pp_kv(pp, 'hash', me.hash)
 883     pp.end_group(ind, ')')
 884 _augment(DSAPub, _tmp)
 885 _augment(KCDSAPub, _tmp)
 886
 887 class _tmp:
 888   def __repr__(me): return '%s(G = %r, u = %s, p = %r, hash = %r)' % \
 889       (_clsname(me), me.G, _repr_secret(me.u), me.p, me.hash)
 890   def _repr_pretty_(me, pp, cyclep):
 891     ind = _pp_bgroup_tyname(pp, me)
 892     if cyclep:
 893       pp.text('...')
 894     else:
 895       _pp_kv(pp, 'G', me.G); pp.text(','); pp.breakable()
 896       _pp_kv(pp, 'u', me.u, True); pp.text(','); pp.breakable()
 897       _pp_kv(pp, 'p', me.p); pp.text(','); pp.breakable()
 898       _pp_kv(pp, 'hash', me.hash)
 899     pp.end_group(ind, ')')
 900 _augment(DSAPriv, _tmp)
 901 _augment(KCDSAPriv, _tmp)
 902
 903 ###--------------------------------------------------------------------------
 904 ### Bernstein's elliptic curve crypto and related schemes.
 905
 906 X25519_BASE = MP(9).storel(32)
 907 X448_BASE = MP(5).storel(56)
 908
 909 Z128 = ByteString.zero(16)
 910
 911 class _BasePub (object):
 912   def __init__(me, pub, *args, **kw):
 913     if not me._PUBSZ.check(len(pub)): raise ValueError('bad public key')
 914     super(_BasePub, me).__init__(*args, **kw)
 915     me.pub = pub
 916   def __repr__(me): return '%s(pub = %r)' % (_clsname(me), me.pub)
 917   def _pp(me, pp): _pp_kv(pp, 'pub', me.pub)
 918   def _repr_pretty_(me, pp, cyclep):
 919     ind = _pp_bgroup_tyname(pp, me)
 920     if cyclep: pp.text('...')
 921     else: me._pp(pp)
 922     pp.end_group(ind, ')')
 923
 924 class _BasePriv (object):
 925   def __init__(me, priv, pub = None, *args, **kw):
 926     if not me._KEYSZ.check(len(priv)): raise ValueError('bad private key')
 927     if pub is None: pub = me._pubkey(priv)
 928     super(_BasePriv, me).__init__(pub = pub, *args, **kw)
 929     me.priv = priv
 930   @classmethod
 931   def generate(cls, rng = rand):
 932     return cls(rng.block(cls._KEYSZ.default))
 933   def __repr__(me):
 934     return '%s(priv = %d, pub = %r)' % \
 935         (_clsname(me), _repr_secret(me.priv), me.pub)
 936   def _pp(me, pp):
 937     _pp_kv(pp, 'priv', me.priv, secretp = True); pp.text(','); pp.breakable()
 938     super(_BasePriv, me)._pp(pp)
 939
 940 class _XDHPub (_BasePub):  pass
 941
 942 class _XDHPriv (_BasePriv):
 943   def _pubkey(me, priv): return me._op(priv, me._BASE)
 944   def agree(me, you): return me._op(me.priv, you.pub)
 945   def boxkey(me, recip): return me._hashkey(me.agree(recip))
 946   def box(me, recip, n, m): return secret_box(me.boxkey(recip), n, m)
 947   def unbox(me, recip, n, c): return secret_unbox(me.boxkey(recip), n, c)
 948
 949 class X25519Pub (_XDHPub):
 950   _PUBSZ = KeySZSet(X25519_PUBSZ)
 951   _BASE = X25519_BASE
 952
 953 class X25519Priv (_XDHPriv, X25519Pub):
 954   _KEYSZ = KeySZSet(X25519_KEYSZ)
 955   def _op(me, k, X): return x25519(k, X)
 956   def _hashkey(me, z): return hsalsa20_prf(z, Z128)
 957
 958 class X448Pub (_XDHPub):
 959   _PUBSZ = KeySZSet(X448_PUBSZ)
 960   _BASE = X448_BASE
 961
 962 class X448Priv (_XDHPriv, X448Pub):
 963   _KEYSZ = KeySZSet(X448_KEYSZ)
 964   def _op(me, k, X): return x448(k, X)
 965   def _hashkey(me, z): return Shake256().hash(z).done(salsa20.keysz.default)
 966
 967 class _EdDSAPub (_BasePub):
 968   def beginhash(me): return me._HASH()
 969   def endhash(me, h): return h.done()
 970
 971 class _EdDSAPriv (_BasePriv, _EdDSAPub):
 972   pass
 973
 974 class Ed25519Pub (_EdDSAPub):
 975   _PUBSZ = KeySZSet(ED25519_PUBSZ)
 976   _HASH = sha512
 977   def verify(me, msg, sig, **kw):
 978     return ed25519_verify(me.pub, msg, sig, **kw)
 979
 980 class Ed25519Priv (_EdDSAPriv, Ed25519Pub):
 981   _KEYSZ = KeySZAny(ED25519_KEYSZ)
 982   def _pubkey(me, priv): return ed25519_pubkey(priv)
 983   def sign(me, msg, **kw):
 984     return ed25519_sign(me.priv, msg, pub = me.pub, **kw)
 985
 986 class Ed448Pub (_EdDSAPub):
 987   _PUBSZ = KeySZSet(ED448_PUBSZ)
 988   _HASH = shake256
 989   def verify(me, msg, sig, **kw):
 990     return ed448_verify(me.pub, msg, sig, **kw)
 991
 992 class Ed448Priv (_EdDSAPriv, Ed448Pub):
 993   _KEYSZ = KeySZAny(ED448_KEYSZ)
 994   def _pubkey(me, priv): return ed448_pubkey(priv)
 995   def sign(me, msg, **kw):
 996     return ed448_sign(me.priv, msg, pub = me.pub, **kw)
 997
 998 ###--------------------------------------------------------------------------
 999 ### Built-in algorithm and group tables.
1000
1001 class _tmp:
1002   def __repr__(me):
1003     return '{%s}' % ', '.join(['%r: %r' % kv for kv in _iteritems(me)])
1004   def _repr_pretty_(me, pp, cyclep):
1005     ind = _pp_bgroup(pp, '{ ')
1006     if cyclep: pp.text('...')
1007     else: _pp_dict(pp, _iteritems(me))
1008     pp.end_group(ind, ' }')
1009 _augment(_base._MiscTable, _tmp)
1010
1011 ###--------------------------------------------------------------------------
1012 ### Prime number generation.
1013
1014 class PrimeGenEventHandler (object):
1015   def pg_begin(me, ev):
1016     return me.pg_try(ev)
1017   def pg_done(me, ev):
1018     return PGEN_DONE
1019   def pg_abort(me, ev):
1020     return PGEN_TRY
1021   def pg_fail(me, ev):
1022     return PGEN_TRY
1023   def pg_pass(me, ev):
1024     return PGEN_TRY
1025
1026 class SophieGermainStepJump (object):
1027   def pg_begin(me, ev):
1028     me.lf = PrimeFilter(ev.x)
1029     me.hf = me.lf.muladd(2, 1)
1030     return me.cont(ev)
1031   def pg_try(me, ev):
1032     me.step()
1033     return me.cont(ev)
1034   def cont(me, ev):
1035     while me.lf.status == PGEN_FAIL or me.hf.status == PGEN_FAIL:
1036       me.step()
1037     if me.lf.status == PGEN_ABORT or me.hf.status == PGEN_ABORT:
1038       return PGEN_ABORT
1039     ev.x = me.lf.x
1040     if me.lf.status == PGEN_DONE and me.hf.status == PGEN_DONE:
1041       return PGEN_DONE
1042     return PGEN_TRY
1043   def pg_done(me, ev):
1044     del me.lf
1045     del me.hf
1046
1047 class SophieGermainStepper (SophieGermainStepJump):
1048   def __init__(me, step):
1049     me.lstep = step;
1050     me.hstep = 2 * step
1051   def step(me):
1052     me.lf.step(me.lstep)
1053     me.hf.step(me.hstep)
1054
1055 class SophieGermainJumper (SophieGermainStepJump):
1056   def __init__(me, jump):
1057     me.ljump = PrimeFilter(jump);
1058     me.hjump = me.ljump.muladd(2, 0)
1059   def step(me):
1060     me.lf.jump(me.ljump)
1061     me.hf.jump(me.hjump)
1062   def pg_done(me, ev):
1063     del me.ljump
1064     del me.hjump
1065     SophieGermainStepJump.pg_done(me, ev)
1066
1067 class SophieGermainTester (object):
1068   def __init__(me):
1069     pass
1070   def pg_begin(me, ev):
1071     me.lr = RabinMiller(ev.x)
1072     me.hr = RabinMiller(2 * ev.x + 1)
1073   def pg_try(me, ev):
1074     lst = me.lr.test(ev.rng.range(me.lr.x))
1075     if lst != PGEN_PASS and lst != PGEN_DONE:
1076       return lst
1077     rst = me.hr.test(ev.rng.range(me.hr.x))
1078     if rst != PGEN_PASS and rst != PGEN_DONE:
1079       return rst
1080     if lst == PGEN_DONE and rst == PGEN_DONE:
1081       return PGEN_DONE
1082     return PGEN_PASS
1083   def pg_done(me, ev):
1084     del me.lr
1085     del me.hr
1086
1087 class PrimitiveStepper (PrimeGenEventHandler):
1088   def __init__(me):
1089     pass
1090   def pg_try(me, ev):
1091     ev.x = me.i.next()
1092     return PGEN_TRY
1093   def pg_begin(me, ev):
1094     me.i = iter(smallprimes)
1095     return me.pg_try(ev)
1096
1097 class PrimitiveTester (PrimeGenEventHandler):
1098   def __init__(me, mod, hh = [], exp = None):
1099     me.mod = MPMont(mod)
1100     me.exp = exp
1101     me.hh = hh
1102   def pg_try(me, ev):
1103     x = ev.x
1104     if me.exp is not None:
1105       x = me.mod.exp(x, me.exp)
1106       if x == 1: return PGEN_FAIL
1107     for h in me.hh:
1108       if me.mod.exp(x, h) == 1: return PGEN_FAIL
1109     ev.x = x
1110     return PGEN_DONE
1111
1112 class SimulStepper (PrimeGenEventHandler):
1113   def __init__(me, mul = 2, add = 1, step = 2):
1114     me.step = step
1115     me.mul = mul
1116     me.add = add
1117   def _stepfn(me, step):
1118     if step <= 0:
1119       raise ValueError('step must be positive')
1120     if step <= MPW_MAX:
1121       return lambda f: f.step(step)
1122     j = PrimeFilter(step)
1123     return lambda f: f.jump(j)
1124   def pg_begin(me, ev):
1125     x = ev.x
1126     me.lf = PrimeFilter(x)
1127     me.hf = PrimeFilter(x * me.mul + me.add)
1128     me.lstep = me._stepfn(me.step)
1129     me.hstep = me._stepfn(me.step * me.mul)
1130     SimulStepper._cont(me, ev)
1131   def pg_try(me, ev):
1132     me._step()
1133     me._cont(ev)
1134   def _step(me):
1135     me.lstep(me.lf)
1136     me.hstep(me.hf)
1137   def _cont(me, ev):
1138     while me.lf.status == PGEN_FAIL or me.hf.status == PGEN_FAIL:
1139       me._step()
1140     if me.lf.status == PGEN_ABORT or me.hf.status == PGEN_ABORT:
1141       return PGEN_ABORT
1142     ev.x = me.lf.x
1143     if me.lf.status == PGEN_DONE and me.hf.status == PGEN_DONE:
1144       return PGEN_DONE
1145     return PGEN_TRY
1146   def pg_done(me, ev):
1147     del me.lf
1148     del me.hf
1149     del me.lstep
1150     del me.hstep
1151
1152 class SimulTester (PrimeGenEventHandler):
1153   def __init__(me, mul = 2, add = 1):
1154     me.mul = mul
1155     me.add = add
1156   def pg_begin(me, ev):
1157     x = ev.x
1158     me.lr = RabinMiller(x)
1159     me.hr = RabinMiller(x * me.mul + me.add)
1160   def pg_try(me, ev):
1161     lst = me.lr.test(ev.rng.range(me.lr.x))
1162     if lst != PGEN_PASS and lst != PGEN_DONE:
1163       return lst
1164     rst = me.hr.test(ev.rng.range(me.hr.x))
1165     if rst != PGEN_PASS and rst != PGEN_DONE:
1166       return rst
1167     if lst == PGEN_DONE and rst == PGEN_DONE:
1168       return PGEN_DONE
1169     return PGEN_PASS
1170   def pg_done(me, ev):
1171     del me.lr
1172     del me.hr
1173
1174 def sgprime(start, step = 2, name = 'p', event = pgen_nullev, nsteps = 0):
1175   start = MP(start)
1176   return pgen(start, name, SimulStepper(step = step), SimulTester(), event,
1177               nsteps, RabinMiller.iters(start.nbits))
1178
1179 def findprimitive(mod, hh = [], exp = None, name = 'g', event = pgen_nullev):
1180   return pgen(0, name, PrimitiveStepper(), PrimitiveTester(mod, hh, exp),
1181               event, 0, 1)
1182
1183 def kcdsaprime(pbits, qbits, rng = rand,
1184                event = pgen_nullev, name = 'p', nsteps = 0):
1185   hbits = pbits - qbits
1186   h = pgen(rng.mp(hbits, 1), name + ' [h]',
1187            PrimeGenStepper(2), PrimeGenTester(),
1188            event, nsteps, RabinMiller.iters(hbits))
1189   q = pgen(rng.mp(qbits, 1), name, SimulStepper(2 * h, 1, 2),
1190            SimulTester(2 * h, 1), event, nsteps, RabinMiller.iters(qbits))
1191   p = 2 * q * h + 1
1192   return p, q, h
1193
1194 #----- That's all, folks ----------------------------------------------------