path: root/passlib/utils/_slow_bcrypt.py

"""passlib._slow_bcrypt - fallback pure-python bcrypt implementation

History
==========
This is a pure-python implementation of the bcrypt hash algorithm,
based off the java bcrypt implementation jBcrypt 0.2,
as downloaded from http://www.mindrot.org/projects/jBCrypt/.

jBcrypt was released under the BSD license::

    Copyright (c) 2006 Damien Miller <djm@mindrot.org>

    Permission to use, copy, modify, and distribute this software for any
    purpose with or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.

    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

This python implementation was adapted from jBcrypt by Eli Collins <elic@astllc.org>,
and released under the BSD license as part of PassLib.

This module is meant mainly as a fall-back for PassLib to use as a last resort.
If you need speedy bcrypt support, install the python-bcrypt library,
and passlib will use it instead of this module.
This module is not suitable for production use, as it's incredibly slow.

The bcrypt unit-tests in passlib.tests.test_bcrypt
will test all bcrypt backends found, not just the preferred one,
in order to ensure no impedance mismatch.
"""
#=========================================================
#imports
#=========================================================
#core
from cStringIO import StringIO
from struct import pack
#pkg
from passlib.utils import rng, getrandbytes
#local
__all__ = [
    'raw_bcrypt',
]
#=========================================================
#bcrypt/blowfish constants
#=========================================================

# BCrypt parameters
BCRYPT_SALT_LEN = 16
BCRYPT_DEFAULT_ROUNDS = 12
BCRYPT_MIN_ROUNDS = 4
BCRYPT_MAX_ROUNDS = 31

# Blowfish parameters
BLOWFISH_NUM_ROUNDS = 16

# Initial contents of key schedule
BLOWFISH_P = [
    0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344,
    0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,
    0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c,
    0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917,
    0x9216d5d9, 0x8979fb1b
]

BLOWFISH_P_LEN = len(BLOWFISH_P)

BLOWFISH_S = [
    0xd1310ba6, 0x98dfb5ac, 0x2ffd72db, 0xd01adfb7,
    0xb8e1afed, 0x6a267e96, 0xba7c9045, 0xf12c7f99,
    0x24a19947, 0xb3916cf7, 0x0801f2e2, 0x858efc16,
    0x636920d8, 0x71574e69, 0xa458fea3, 0xf4933d7e,
    0x0d95748f, 0x728eb658, 0x718bcd58, 0x82154aee,
    0x7b54a41d, 0xc25a59b5, 0x9c30d539, 0x2af26013,
    0xc5d1b023, 0x286085f0, 0xca417918, 0xb8db38ef,
    0x8e79dcb0, 0x603a180e, 0x6c9e0e8b, 0xb01e8a3e,
    0xd71577c1, 0xbd314b27, 0x78af2fda, 0x55605c60,
    0xe65525f3, 0xaa55ab94, 0x57489862, 0x63e81440,
    0x55ca396a, 0x2aab10b6, 0xb4cc5c34, 0x1141e8ce,
    0xa15486af, 0x7c72e993, 0xb3ee1411, 0x636fbc2a,
    0x2ba9c55d, 0x741831f6, 0xce5c3e16, 0x9b87931e,
    0xafd6ba33, 0x6c24cf5c, 0x7a325381, 0x28958677,
    0x3b8f4898, 0x6b4bb9af, 0xc4bfe81b, 0x66282193,
    0x61d809cc, 0xfb21a991, 0x487cac60, 0x5dec8032,
    0xef845d5d, 0xe98575b1, 0xdc262302, 0xeb651b88,
    0x23893e81, 0xd396acc5, 0x0f6d6ff3, 0x83f44239,
    0x2e0b4482, 0xa4842004, 0x69c8f04a, 0x9e1f9b5e,
    0x21c66842, 0xf6e96c9a, 0x670c9c61, 0xabd388f0,
    0x6a51a0d2, 0xd8542f68, 0x960fa728, 0xab5133a3,
    0x6eef0b6c, 0x137a3be4, 0xba3bf050, 0x7efb2a98,
    0xa1f1651d, 0x39af0176, 0x66ca593e, 0x82430e88,
    0x8cee8619, 0x456f9fb4, 0x7d84a5c3, 0x3b8b5ebe,
    0xe06f75d8, 0x85c12073, 0x401a449f, 0x56c16aa6,
    0x4ed3aa62, 0x363f7706, 0x1bfedf72, 0x429b023d,
    0x37d0d724, 0xd00a1248, 0xdb0fead3, 0x49f1c09b,
    0x075372c9, 0x80991b7b, 0x25d479d8, 0xf6e8def7,
    0xe3fe501a, 0xb6794c3b, 0x976ce0bd, 0x04c006ba,
    0xc1a94fb6, 0x409f60c4, 0x5e5c9ec2, 0x196a2463,
    0x68fb6faf, 0x3e6c53b5, 0x1339b2eb, 0x3b52ec6f,
    0x6dfc511f, 0x9b30952c, 0xcc814544, 0xaf5ebd09,
    0xbee3d004, 0xde334afd, 0x660f2807, 0x192e4bb3,
    0xc0cba857, 0x45c8740f, 0xd20b5f39, 0xb9d3fbdb,
    0x5579c0bd, 0x1a60320a, 0xd6a100c6, 0x402c7279,
    0x679f25fe, 0xfb1fa3cc, 0x8ea5e9f8, 0xdb3222f8,
    0x3c7516df, 0xfd616b15, 0x2f501ec8, 0xad0552ab,
    0x323db5fa, 0xfd238760, 0x53317b48, 0x3e00df82,
    0x9e5c57bb, 0xca6f8ca0, 0x1a87562e, 0xdf1769db,
    0xd542a8f6, 0x287effc3, 0xac6732c6, 0x8c4f5573,
    0x695b27b0, 0xbbca58c8, 0xe1ffa35d, 0xb8f011a0,
    0x10fa3d98, 0xfd2183b8, 0x4afcb56c, 0x2dd1d35b,
    0x9a53e479, 0xb6f84565, 0xd28e49bc, 0x4bfb9790,
    0xe1ddf2da, 0xa4cb7e33, 0x62fb1341, 0xcee4c6e8,
    0xef20cada, 0x36774c01, 0xd07e9efe, 0x2bf11fb4,
    0x95dbda4d, 0xae909198, 0xeaad8e71, 0x6b93d5a0,
    0xd08ed1d0, 0xafc725e0, 0x8e3c5b2f, 0x8e7594b7,
    0x8ff6e2fb, 0xf2122b64, 0x8888b812, 0x900df01c,
    0x4fad5ea0, 0x688fc31c, 0xd1cff191, 0xb3a8c1ad,
    0x2f2f2218, 0xbe0e1777, 0xea752dfe, 0x8b021fa1,
    0xe5a0cc0f, 0xb56f74e8, 0x18acf3d6, 0xce89e299,
    0xb4a84fe0, 0xfd13e0b7, 0x7cc43b81, 0xd2ada8d9,
    0x165fa266, 0x80957705, 0x93cc7314, 0x211a1477,
    0xe6ad2065, 0x77b5fa86, 0xc75442f5, 0xfb9d35cf,
    0xebcdaf0c, 0x7b3e89a0, 0xd6411bd3, 0xae1e7e49,
    0x00250e2d, 0x2071b35e, 0x226800bb, 0x57b8e0af,
    0x2464369b, 0xf009b91e, 0x5563911d, 0x59dfa6aa,
    0x78c14389, 0xd95a537f, 0x207d5ba2, 0x02e5b9c5,
    0x83260376, 0x6295cfa9, 0x11c81968, 0x4e734a41,
    0xb3472dca, 0x7b14a94a, 0x1b510052, 0x9a532915,
    0xd60f573f, 0xbc9bc6e4, 0x2b60a476, 0x81e67400,
    0x08ba6fb5, 0x571be91f, 0xf296ec6b, 0x2a0dd915,
    0xb6636521, 0xe7b9f9b6, 0xff34052e, 0xc5855664,
    0x53b02d5d, 0xa99f8fa1, 0x08ba4799, 0x6e85076a,
    0x4b7a70e9, 0xb5b32944, 0xdb75092e, 0xc4192623,
    0xad6ea6b0, 0x49a7df7d, 0x9cee60b8, 0x8fedb266,
    0xecaa8c71, 0x699a17ff, 0x5664526c, 0xc2b19ee1,
    0x193602a5, 0x75094c29, 0xa0591340, 0xe4183a3e,
    0x3f54989a, 0x5b429d65, 0x6b8fe4d6, 0x99f73fd6,
    0xa1d29c07, 0xefe830f5, 0x4d2d38e6, 0xf0255dc1,
    0x4cdd2086, 0x8470eb26, 0x6382e9c6, 0x021ecc5e,
    0x09686b3f, 0x3ebaefc9, 0x3c971814, 0x6b6a70a1,
    0x687f3584, 0x52a0e286, 0xb79c5305, 0xaa500737,
    0x3e07841c, 0x7fdeae5c, 0x8e7d44ec, 0x5716f2b8,
    0xb03ada37, 0xf0500c0d, 0xf01c1f04, 0x0200b3ff,
    0xae0cf51a, 0x3cb574b2, 0x25837a58, 0xdc0921bd,
    0xd19113f9, 0x7ca92ff6, 0x94324773, 0x22f54701,
    0x3ae5e581, 0x37c2dadc, 0xc8b57634, 0x9af3dda7,
    0xa9446146, 0x0fd0030e, 0xecc8c73e, 0xa4751e41,
    0xe238cd99, 0x3bea0e2f, 0x3280bba1, 0x183eb331,
    0x4e548b38, 0x4f6db908, 0x6f420d03, 0xf60a04bf,
    0x2cb81290, 0x24977c79, 0x5679b072, 0xbcaf89af,
    0xde9a771f, 0xd9930810, 0xb38bae12, 0xdccf3f2e,
    0x5512721f, 0x2e6b7124, 0x501adde6, 0x9f84cd87,
    0x7a584718, 0x7408da17, 0xbc9f9abc, 0xe94b7d8c,
    0xec7aec3a, 0xdb851dfa, 0x63094366, 0xc464c3d2,
    0xef1c1847, 0x3215d908, 0xdd433b37, 0x24c2ba16,
    0x12a14d43, 0x2a65c451, 0x50940002, 0x133ae4dd,
    0x71dff89e, 0x10314e55, 0x81ac77d6, 0x5f11199b,
    0x043556f1, 0xd7a3c76b, 0x3c11183b, 0x5924a509,
    0xf28fe6ed, 0x97f1fbfa, 0x9ebabf2c, 0x1e153c6e,
    0x86e34570, 0xeae96fb1, 0x860e5e0a, 0x5a3e2ab3,
    0x771fe71c, 0x4e3d06fa, 0x2965dcb9, 0x99e71d0f,
    0x803e89d6, 0x5266c825, 0x2e4cc978, 0x9c10b36a,
    0xc6150eba, 0x94e2ea78, 0xa5fc3c53, 0x1e0a2df4,
    0xf2f74ea7, 0x361d2b3d, 0x1939260f, 0x19c27960,
    0x5223a708, 0xf71312b6, 0xebadfe6e, 0xeac31f66,
    0xe3bc4595, 0xa67bc883, 0xb17f37d1, 0x018cff28,
    0xc332ddef, 0xbe6c5aa5, 0x65582185, 0x68ab9802,
    0xeecea50f, 0xdb2f953b, 0x2aef7dad, 0x5b6e2f84,
    0x1521b628, 0x29076170, 0xecdd4775, 0x619f1510,
    0x13cca830, 0xeb61bd96, 0x0334fe1e, 0xaa0363cf,
    0xb5735c90, 0x4c70a239, 0xd59e9e0b, 0xcbaade14,
    0xeecc86bc, 0x60622ca7, 0x9cab5cab, 0xb2f3846e,
    0x648b1eaf, 0x19bdf0ca, 0xa02369b9, 0x655abb50,
    0x40685a32, 0x3c2ab4b3, 0x319ee9d5, 0xc021b8f7,
    0x9b540b19, 0x875fa099, 0x95f7997e, 0x623d7da8,
    0xf837889a, 0x97e32d77, 0x11ed935f, 0x16681281,
    0x0e358829, 0xc7e61fd6, 0x96dedfa1, 0x7858ba99,
    0x57f584a5, 0x1b227263, 0x9b83c3ff, 0x1ac24696,
    0xcdb30aeb, 0x532e3054, 0x8fd948e4, 0x6dbc3128,
    0x58ebf2ef, 0x34c6ffea, 0xfe28ed61, 0xee7c3c73,
    0x5d4a14d9, 0xe864b7e3, 0x42105d14, 0x203e13e0,
    0x45eee2b6, 0xa3aaabea, 0xdb6c4f15, 0xfacb4fd0,
    0xc742f442, 0xef6abbb5, 0x654f3b1d, 0x41cd2105,
    0xd81e799e, 0x86854dc7, 0xe44b476a, 0x3d816250,
    0xcf62a1f2, 0x5b8d2646, 0xfc8883a0, 0xc1c7b6a3,
    0x7f1524c3, 0x69cb7492, 0x47848a0b, 0x5692b285,
    0x095bbf00, 0xad19489d, 0x1462b174, 0x23820e00,
    0x58428d2a, 0x0c55f5ea, 0x1dadf43e, 0x233f7061,
    0x3372f092, 0x8d937e41, 0xd65fecf1, 0x6c223bdb,
    0x7cde3759, 0xcbee7460, 0x4085f2a7, 0xce77326e,
    0xa6078084, 0x19f8509e, 0xe8efd855, 0x61d99735,
    0xa969a7aa, 0xc50c06c2, 0x5a04abfc, 0x800bcadc,
    0x9e447a2e, 0xc3453484, 0xfdd56705, 0x0e1e9ec9,
    0xdb73dbd3, 0x105588cd, 0x675fda79, 0xe3674340,
    0xc5c43465, 0x713e38d8, 0x3d28f89e, 0xf16dff20,
    0x153e21e7, 0x8fb03d4a, 0xe6e39f2b, 0xdb83adf7,
    0xe93d5a68, 0x948140f7, 0xf64c261c, 0x94692934,
    0x411520f7, 0x7602d4f7, 0xbcf46b2e, 0xd4a20068,
    0xd4082471, 0x3320f46a, 0x43b7d4b7, 0x500061af,
    0x1e39f62e, 0x97244546, 0x14214f74, 0xbf8b8840,
    0x4d95fc1d, 0x96b591af, 0x70f4ddd3, 0x66a02f45,
    0xbfbc09ec, 0x03bd9785, 0x7fac6dd0, 0x31cb8504,
    0x96eb27b3, 0x55fd3941, 0xda2547e6, 0xabca0a9a,
    0x28507825, 0x530429f4, 0x0a2c86da, 0xe9b66dfb,
    0x68dc1462, 0xd7486900, 0x680ec0a4, 0x27a18dee,
    0x4f3ffea2, 0xe887ad8c, 0xb58ce006, 0x7af4d6b6,
    0xaace1e7c, 0xd3375fec, 0xce78a399, 0x406b2a42,
    0x20fe9e35, 0xd9f385b9, 0xee39d7ab, 0x3b124e8b,
    0x1dc9faf7, 0x4b6d1856, 0x26a36631, 0xeae397b2,
    0x3a6efa74, 0xdd5b4332, 0x6841e7f7, 0xca7820fb,
    0xfb0af54e, 0xd8feb397, 0x454056ac, 0xba489527,
    0x55533a3a, 0x20838d87, 0xfe6ba9b7, 0xd096954b,
    0x55a867bc, 0xa1159a58, 0xcca92963, 0x99e1db33,
    0xa62a4a56, 0x3f3125f9, 0x5ef47e1c, 0x9029317c,
    0xfdf8e802, 0x04272f70, 0x80bb155c, 0x05282ce3,
    0x95c11548, 0xe4c66d22, 0x48c1133f, 0xc70f86dc,
    0x07f9c9ee, 0x41041f0f, 0x404779a4, 0x5d886e17,
    0x325f51eb, 0xd59bc0d1, 0xf2bcc18f, 0x41113564,
    0x257b7834, 0x602a9c60, 0xdff8e8a3, 0x1f636c1b,
    0x0e12b4c2, 0x02e1329e, 0xaf664fd1, 0xcad18115,
    0x6b2395e0, 0x333e92e1, 0x3b240b62, 0xeebeb922,
    0x85b2a20e, 0xe6ba0d99, 0xde720c8c, 0x2da2f728,
    0xd0127845, 0x95b794fd, 0x647d0862, 0xe7ccf5f0,
    0x5449a36f, 0x877d48fa, 0xc39dfd27, 0xf33e8d1e,
    0x0a476341, 0x992eff74, 0x3a6f6eab, 0xf4f8fd37,
    0xa812dc60, 0xa1ebddf8, 0x991be14c, 0xdb6e6b0d,
    0xc67b5510, 0x6d672c37, 0x2765d43b, 0xdcd0e804,
    0xf1290dc7, 0xcc00ffa3, 0xb5390f92, 0x690fed0b,
    0x667b9ffb, 0xcedb7d9c, 0xa091cf0b, 0xd9155ea3,
    0xbb132f88, 0x515bad24, 0x7b9479bf, 0x763bd6eb,
    0x37392eb3, 0xcc115979, 0x8026e297, 0xf42e312d,
    0x6842ada7, 0xc66a2b3b, 0x12754ccc, 0x782ef11c,
    0x6a124237, 0xb79251e7, 0x06a1bbe6, 0x4bfb6350,
    0x1a6b1018, 0x11caedfa, 0x3d25bdd8, 0xe2e1c3c9,
    0x44421659, 0x0a121386, 0xd90cec6e, 0xd5abea2a,
    0x64af674e, 0xda86a85f, 0xbebfe988, 0x64e4c3fe,
    0x9dbc8057, 0xf0f7c086, 0x60787bf8, 0x6003604d,
    0xd1fd8346, 0xf6381fb0, 0x7745ae04, 0xd736fccc,
    0x83426b33, 0xf01eab71, 0xb0804187, 0x3c005e5f,
    0x77a057be, 0xbde8ae24, 0x55464299, 0xbf582e61,
    0x4e58f48f, 0xf2ddfda2, 0xf474ef38, 0x8789bdc2,
    0x5366f9c3, 0xc8b38e74, 0xb475f255, 0x46fcd9b9,
    0x7aeb2661, 0x8b1ddf84, 0x846a0e79, 0x915f95e2,
    0x466e598e, 0x20b45770, 0x8cd55591, 0xc902de4c,
    0xb90bace1, 0xbb8205d0, 0x11a86248, 0x7574a99e,
    0xb77f19b6, 0xe0a9dc09, 0x662d09a1, 0xc4324633,
    0xe85a1f02, 0x09f0be8c, 0x4a99a025, 0x1d6efe10,
    0x1ab93d1d, 0x0ba5a4df, 0xa186f20f, 0x2868f169,
    0xdcb7da83, 0x573906fe, 0xa1e2ce9b, 0x4fcd7f52,
    0x50115e01, 0xa70683fa, 0xa002b5c4, 0x0de6d027,
    0x9af88c27, 0x773f8641, 0xc3604c06, 0x61a806b5,
    0xf0177a28, 0xc0f586e0, 0x006058aa, 0x30dc7d62,
    0x11e69ed7, 0x2338ea63, 0x53c2dd94, 0xc2c21634,
    0xbbcbee56, 0x90bcb6de, 0xebfc7da1, 0xce591d76,
    0x6f05e409, 0x4b7c0188, 0x39720a3d, 0x7c927c24,
    0x86e3725f, 0x724d9db9, 0x1ac15bb4, 0xd39eb8fc,
    0xed545578, 0x08fca5b5, 0xd83d7cd3, 0x4dad0fc4,
    0x1e50ef5e, 0xb161e6f8, 0xa28514d9, 0x6c51133c,
    0x6fd5c7e7, 0x56e14ec4, 0x362abfce, 0xddc6c837,
    0xd79a3234, 0x92638212, 0x670efa8e, 0x406000e0,
    0x3a39ce37, 0xd3faf5cf, 0xabc27737, 0x5ac52d1b,
    0x5cb0679e, 0x4fa33742, 0xd3822740, 0x99bc9bbe,
    0xd5118e9d, 0xbf0f7315, 0xd62d1c7e, 0xc700c47b,
    0xb78c1b6b, 0x21a19045, 0xb26eb1be, 0x6a366eb4,
    0x5748ab2f, 0xbc946e79, 0xc6a376d2, 0x6549c2c8,
    0x530ff8ee, 0x468dde7d, 0xd5730a1d, 0x4cd04dc6,
    0x2939bbdb, 0xa9ba4650, 0xac9526e8, 0xbe5ee304,
    0xa1fad5f0, 0x6a2d519a, 0x63ef8ce2, 0x9a86ee22,
    0xc089c2b8, 0x43242ef6, 0xa51e03aa, 0x9cf2d0a4,
    0x83c061ba, 0x9be96a4d, 0x8fe51550, 0xba645bd6,
    0x2826a2f9, 0xa73a3ae1, 0x4ba99586, 0xef5562e9,
    0xc72fefd3, 0xf752f7da, 0x3f046f69, 0x77fa0a59,
    0x80e4a915, 0x87b08601, 0x9b09e6ad, 0x3b3ee593,
    0xe990fd5a, 0x9e34d797, 0x2cf0b7d9, 0x022b8b51,
    0x96d5ac3a, 0x017da67d, 0xd1cf3ed6, 0x7c7d2d28,
    0x1f9f25cf, 0xadf2b89b, 0x5ad6b472, 0x5a88f54c,
    0xe029ac71, 0xe019a5e6, 0x47b0acfd, 0xed93fa9b,
    0xe8d3c48d, 0x283b57cc, 0xf8d56629, 0x79132e28,
    0x785f0191, 0xed756055, 0xf7960e44, 0xe3d35e8c,
    0x15056dd4, 0x88f46dba, 0x03a16125, 0x0564f0bd,
    0xc3eb9e15, 0x3c9057a2, 0x97271aec, 0xa93a072a,
    0x1b3f6d9b, 0x1e6321f5, 0xf59c66fb, 0x26dcf319,
    0x7533d928, 0xb155fdf5, 0x03563482, 0x8aba3cbb,
    0x28517711, 0xc20ad9f8, 0xabcc5167, 0xccad925f,
    0x4de81751, 0x3830dc8e, 0x379d5862, 0x9320f991,
    0xea7a90c2, 0xfb3e7bce, 0x5121ce64, 0x774fbe32,
    0xa8b6e37e, 0xc3293d46, 0x48de5369, 0x6413e680,
    0xa2ae0810, 0xdd6db224, 0x69852dfd, 0x09072166,
    0xb39a460a, 0x6445c0dd, 0x586cdecf, 0x1c20c8ae,
    0x5bbef7dd, 0x1b588d40, 0xccd2017f, 0x6bb4e3bb,
    0xdda26a7e, 0x3a59ff45, 0x3e350a44, 0xbcb4cdd5,
    0x72eacea8, 0xfa6484bb, 0x8d6612ae, 0xbf3c6f47,
    0xd29be463, 0x542f5d9e, 0xaec2771b, 0xf64e6370,
    0x740e0d8d, 0xe75b1357, 0xf8721671, 0xaf537d5d,
    0x4040cb08, 0x4eb4e2cc, 0x34d2466a, 0x0115af84,
    0xe1b00428, 0x95983a1d, 0x06b89fb4, 0xce6ea048,
    0x6f3f3b82, 0x3520ab82, 0x011a1d4b, 0x277227f8,
    0x611560b1, 0xe7933fdc, 0xbb3a792b, 0x344525bd,
    0xa08839e1, 0x51ce794b, 0x2f32c9b7, 0xa01fbac9,
    0xe01cc87e, 0xbcc7d1f6, 0xcf0111c3, 0xa1e8aac7,
    0x1a908749, 0xd44fbd9a, 0xd0dadecb, 0xd50ada38,
    0x0339c32a, 0xc6913667, 0x8df9317c, 0xe0b12b4f,
    0xf79e59b7, 0x43f5bb3a, 0xf2d519ff, 0x27d9459c,
    0xbf97222c, 0x15e6fc2a, 0x0f91fc71, 0x9b941525,
    0xfae59361, 0xceb69ceb, 0xc2a86459, 0x12baa8d1,
    0xb6c1075e, 0xe3056a0c, 0x10d25065, 0xcb03a442,
    0xe0ec6e0e, 0x1698db3b, 0x4c98a0be, 0x3278e964,
    0x9f1f9532, 0xe0d392df, 0xd3a0342b, 0x8971f21e,
    0x1b0a7441, 0x4ba3348c, 0xc5be7120, 0xc37632d8,
    0xdf359f8d, 0x9b992f2e, 0xe60b6f47, 0x0fe3f11d,
    0xe54cda54, 0x1edad891, 0xce6279cf, 0xcd3e7e6f,
    0x1618b166, 0xfd2c1d05, 0x848fd2c5, 0xf6fb2299,
    0xf523f357, 0xa6327623, 0x93a83531, 0x56cccd02,
    0xacf08162, 0x5a75ebb5, 0x6e163697, 0x88d273cc,
    0xde966292, 0x81b949d0, 0x4c50901b, 0x71c65614,
    0xe6c6c7bd, 0x327a140a, 0x45e1d006, 0xc3f27b9a,
    0xc9aa53fd, 0x62a80f00, 0xbb25bfe2, 0x35bdd2f6,
    0x71126905, 0xb2040222, 0xb6cbcf7c, 0xcd769c2b,
    0x53113ec0, 0x1640e3d3, 0x38abbd60, 0x2547adf0,
    0xba38209c, 0xf746ce76, 0x77afa1c5, 0x20756060,
    0x85cbfe4e, 0x8ae88dd8, 0x7aaaf9b0, 0x4cf9aa7e,
    0x1948c25c, 0x02fb8a8c, 0x01c36ae4, 0xd6ebe1f9,
    0x90d4f869, 0xa65cdea0, 0x3f09252d, 0xc208e69f,
    0xb74e6132, 0xce77e25b, 0x578fdfe3, 0x3ac372e6
];

BLOWFISH_S_LEN = len(BLOWFISH_S)

# bcrypt IV: "OrpheanBeholderScryDoubt"
BF_CRYPT_CIPHERTEXT = [ # 6 int
    0x4f727068, 0x65616e42, 0x65686f6c,
    0x64657253, 0x63727944, 0x6f756274
]

BF_CRYPT_CIPHERLEN = len(BF_CRYPT_CIPHERTEXT)

#(unencoded) length of bcrypt chk length
BCRYPT_CHK_LEN = len(BF_CRYPT_CIPHERTEXT)*4-1

#=========================================================
#base64 encoding
#=========================================================

# Table for Base64 encoding
CHARS = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
CHARSIDX = dict( (c, i) for i, c in enumerate(CHARS))

def encode_base64(d):
    """Encode a byte array using bcrypt's slightly-modified base64 encoding scheme.

    Note that this is *not* compatible with the standard MIME-base64 encoding.

    :param d:
        the bytes to encode
    :returns:
        the bytes as encoded using bcrypt's base64
    """
    if isinstance(d, unicode):
        d = d.encode("utf-8")
        #ensure ord() returns something w/in 0..255

    rs = StringIO()
    write = rs.write
    dlen = len(d)
    didx = 0

    while True:
        #encode first byte ->  1 byte (6 bits) w/ 2 bits left over
        if didx >= dlen:
            break
        c1 = ord(d[didx])
        write(CHARS[(c1 >> 2) & 0x3f])
        c1 = (c1 & 0x03) << 4
        didx += 1

        #encode 2 bits + second byte -> 1 byte (6 bits) w/ 4 bits left over
        if didx >= dlen:
            write(CHARS[c1])
            break
        c2 = ord(d[didx])
        write(CHARS[c1 | (c2 >> 4) ])
        c2 = (c2 & 0x0f) << 2
        didx += 1

        #encode 4 bits left over + third byte -> 1 byte (6 bits) w/ 2 bits left over
        if didx >= dlen:
            write(CHARS[c2])
            break
        c3 = ord(d[didx])
        write(CHARS[c2 | (c3 >> 6)])
        write(CHARS[c3 & 0x3f])
        didx += 1

    return rs.getvalue()

def decode_base64(s):
    """Decode bytes encoded using bcrypt's base64 scheme.

    :param s:
        string of bcrypt-base64 encoded bytes

    :returns:
        string of decoded bytes

    :raises ValueError:
        if invalid values are passed in
    """
    rs = StringIO()
    write = rs.write
    slen = len(s)
    sidx = 0

    def char64(c):
        "look up 6 bit value in table"
        try:
            return CHARSIDX[c]
        except KeyError:
            raise ValueError, "invalid chars in base64 string"

    while True:

        #decode byte 1 + byte 2 -> 1 byte + 4 bits left over
        if sidx >= slen-1:
            break
        c2 = char64(s[sidx+1])
        write(chr((char64(s[sidx]) << 2) | (c2 >> 4)))
        sidx += 2

        #decode 4 bits left over + 3rd byte -> 1 byte + 2 bits left over
        if sidx >= slen:
            break
        c3 = char64(s[sidx])
        write(chr(((c2 & 0x0f) << 4) | (c3 >> 2)))
        sidx += 1

        #decode 2 bits left over + 4th byte -> 1 byte
        if sidx >= slen:
            break
        write(chr(((c3 & 0x03) << 6) | char64(s[sidx])))
        sidx += 1

    return rs.getvalue()

#=========================================================
#helpers
#=========================================================
def iter_cyclic_words(data):
    """return generator which translates bytes into sequence of word-sized ints;
    cyclically restarting at beginning when it reaches end"""
    off = 0
    dlen = len(data)

    #duplicate data chunk until it's a multiple of 4.
    #this make the loop cheaper to iterate
    m = dlen % 4
    if m == 1 or m == 3:
        dlen <<= 2
        data *= 4
    elif m == 2:
        dlen <<= 1
        data *= 2

    while True:
        yield (
            (ord(data[off])<<24) +
            (ord(data[off+1])<<16) +
            (ord(data[off+2])<<8) +
            (ord(data[off+3]))
        )
        off += 4
        if off == dlen:
            off = 0
        assert off < dlen

#=========================================================
#base bcrypt helper
#
#interface designed only for use by passlib.drivers.bcrypt.BCrypt
#probably not suitable for other purposes
#=========================================================

RPLEN = range(0, BLOWFISH_P_LEN)
RPLEN_S2 = range(0, BLOWFISH_P_LEN, 2)
RSLEN_S2 = range(0, BLOWFISH_S_LEN, 2)

RRND_S2 = range(0, BLOWFISH_NUM_ROUNDS-1, 2)
RRND_S4 = range(0, BLOWFISH_NUM_ROUNDS-1, 4)
RCLEN_S2 = range(0, BF_CRYPT_CIPHERLEN, 2)

BLOWFISH_NUM_ROUNDS_ONE = BLOWFISH_NUM_ROUNDS+1

MASK_32 = 0xFfffFfff

CHK_PACK = ">" + "I" * BF_CRYPT_CIPHERLEN

def raw_bcrypt(password, ident, salt, log_rounds):
    """perform central password hashing step in bcrypt scheme.

    :param password: the password to hash
    :param ident: identifier w/ minor version (eg 2, 2a)
    :param salt: the binary salt to use (encoded in bcrypt-base64)
    :param rounds: the log2 of the number of rounds (as int)
    :returns: bcrypt-base64 encoded checksum
    """
    #
    #parse inputs
    #

    #parse ident
    if ident == '2':
        minor = 0
    elif ident == '2a':
        minor = 1
    else:
        raise ValueError, "unknown ident: %r" % (ident,)

    #decode & validate salt
    salt = decode_base64(salt)
    if len(salt) < BCRYPT_SALT_LEN:
        raise ValueError, "Missing salt bytes"
    elif len(salt) > BCRYPT_SALT_LEN:
        salt = salt[:BCRYPT_SALT_LEN]

    #prepare password
    password = password.encode("utf-8")
    if minor > 0:
        password += '\x00'

    #validate rounds
    if log_rounds < BCRYPT_MIN_ROUNDS or log_rounds > BCRYPT_MAX_ROUNDS:
        raise ValueError, "Bad number of rounds"

    #
    #init blowfish key schedule
    #
    P = list(BLOWFISH_P)
    S = list(BLOWFISH_S)

    def encipher(l, r):
        """Blowfish encipher a single 64-bit block encoded as two 32-bit halves"""
        l ^= P[0]
        for i in RRND_S2:
            # Feistel substitution on left word
            r ^= ((((S[(l >> 24) & 0xff] +
                     S[0x100 | ((l >> 16) & 0xff)]
                    ) ^ S[0x200 | ((l >> 8) & 0xff)]
                   ) + S[0x300 | (l & 0xff)]
                  ) & MASK_32
                 ) ^ P[i+1]
            # Feistel substitution on right word
            l ^= ((((S[(r >> 24) & 0xff] +
                     S[0x100 | ((r >> 16) & 0xff)]
                    ) ^ S[0x200 | ((r >> 8) & 0xff)]
                   ) + S[0x300 | (r & 0xff)]
                  ) & MASK_32
                 ) ^ P[i+2]
        return r ^ P[BLOWFISH_NUM_ROUNDS_ONE], l

    #
    #Perform the "enhanced key schedule" step described by
    #Provos and Mazieres in "A Future-Adaptable Password Scheme"
    #http:#www.openbsd.org/papers/bcrypt-paper.ps
    #
    #uses password as key, salt as data
    #
    pass_iter = iter_cyclic_words(password).next
    for i in RPLEN: ##xrange(BLOWFISH_P_LEN):
        P[i] = P[i] ^ pass_iter() #streamtoword(password, koffp)

    l = r = 0
    salt_iter = iter_cyclic_words(salt).next
    for i in RPLEN_S2: ##xrange(0, BLOWFISH_P_LEN, 2):
        l ^= salt_iter() #streamtoword(salt, doffp)
        r ^= salt_iter() #streamtoword(salt, doffp)
        P[i], P[i+1] = l,r = encipher(l,r)

    for i in RSLEN_S2: ##xrange(0, BLOWFISH_S_LEN, 2):
        l ^= salt_iter() #streamtoword(salt, doffp)
        r ^= salt_iter() #streamtoword(salt, doffp)
        S[i], S[i+1] = l,r = encipher(l,r)

    #
    #precalculate key arrays for the rounds
    #
    def mkarray(key):
        key_iter = iter_cyclic_words(key).next
        return [
            (i, key_iter())
            for i in RPLEN ##xrange(BLOWFISH_P_LEN)
        ]
    key_word_arrays = [
        mkarray(password),
        mkarray(salt)
    ]

    #
    #apply password & salt keys to key schedule
    #
    rounds = 1<<log_rounds
    while rounds:
        rounds -= 1
        for key_words in key_word_arrays:
            #
            #key the Blowfish cipher
            #
            for i, word in key_words:
                P[i] ^= word
            l = r = 0
            for i in RPLEN_S2:
                P[i], P[i+1] = l,r = encipher(l,r)
            for i in RSLEN_S2:
                S[i], S[i+1] = l,r = encipher(l,r)

    #
    #encipher constant data
    #
    cdata = list(BF_CRYPT_CIPHERTEXT)
    for j in RCLEN_S2:
        l,r = cdata[j], cdata[j+1]
        rounds = 64
        while rounds:
            rounds -= 1
            l,r=encipher(l,r)
        cdata[j], cdata[j+1] = l,r

    #
    #encode cdata buffer to bytes
    #
    raw = pack(CHK_PACK, *cdata)[:-1]
    return encode_base64(raw)

#=========================================================
#eof
#=========================================================