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