# blowfish
# Copyright (C) 2014 Jashandeep Sohi <jashandeep.s.sohi@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

"""
This module implements the Blowfish cipher using only Python (3.4+).

Blowfish is a block cipher created by Bruce Schneier. It's fast, free and
well tested. More at <https://www.schneier.com/blowfish.html>.
"""

from struct import Struct

__version__ = "0.4.0"

# _PI_P_ARRAY & _PI_S_BOXES are the hexadecimal digits of π (the irrational)
# taken from <https://www.schneier.com/code/constants.txt>.

# 1 x 18
_PI_P_ARRAY = (
  0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344, 0xa4093822, 0x299f31d0,
  0x082efa98, 0xec4e6c89, 0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c,
  0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917, 0x9216d5d9, 0x8979fb1b,
)

# 4 x 256
_PI_S_BOXES = (
  (
    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,
  ),
)

class Cipher(object):
  """
  Blowfish block cipher.
  
  Instantiate
  -----------
  `key` should be a :obj:`bytes` object with a length between 8 and 56 bytes.
  
  `byte_order` can either be ``"big"`` or ``"little"``. The default value of
  ``"big"`` rarely needs to be changed, since most implementations of Blowfish
  use big endian byte order to convert the bytes into numbers to perform the
  mathematical operations.
  
  `P_array` and `S_boxes` are the initial P array and substitution boxes used
  to derive the key dependent P array and S-boxes. By default these are set to
  the digits of pi (in hexadecimal).
  If you would like to experiment with your own values (and you know what you
  are doing!), then `P_array` should be a 1D sequence of integers and `S_boxes`
  should be a 4 x 256 2D sequence of integers.
  `P_array` can be an arbitrary length, which determines how many rounds of
  Blowfish are done per block.
  

  Encryption & Decryption
  -----------------------
  Blowfish is a block cipher with a block size of 64-bits. As such, encryption
  and decryption are only done on 64-bits of data.
  
  To encrypt and decrypt a single block of data use the :meth:`encrypt_block`
  and :meth:`decrypt_block` methods.
  
  Usually, you'll want to use a mode of operation to encrypt or decrypt
  data. So far the following modes of operations have been implemented.
  
  +---------------------------+----------------------+----------------------+
  | Mode of Operation         | Encryption           | Decryption           |
  +===========================+======================+======================+
  | Electronic Codebook (ECB) | :meth:`encrypt_ecb`  | :meth:`decrypt_ecb`  |
  +---------------------------+----------------------+----------------------+
  | Cipher-Block Chaining     | :meth:`encrypt_cbc`  | :meth:`decrypt_cbc`  |
  | (CBC)                     |                      |                      |
  +---------------------------+----------------------+----------------------+
  | Propagating Cipher-Block  | :meth:`encrypt_pcbc` | :meth:`decrypt_pcbc` |
  | Chaining (PCBC)           |                      |                      |
  +---------------------------+----------------------+----------------------+
  | Cipher Feedback (CFB)     | :meth:`encrypt_cfb`  | :meth:`decrypt_cfb`  |
  +---------------------------+----------------------+----------------------+
  | Output Feedback (OFB)     | :meth:`encrypt_ofb`  | :meth:`decrypt_ofb`  |
  +---------------------------+----------------------+----------------------+
  | Counter (CTR)             | :meth:`encrypt_ctr`  | :meth:`decrypt_ctr`  |
  +---------------------------+----------------------+----------------------+
  
  All of the modes, except for CTR, expect that the data given to them have a
  size a multiple of the block size (i.e. 64-bits, 128-bits, etc).
  Non-block-multiple data can be used if it is padded properly. Currently,
  padding logic is not implemented by this module, so you are responsible for
  the padding.
  
  .. warning::
      
      Some modes have weaknesses and quirks, so please read up on them before
      using them. If you can't be bothered, stick with CTR.
  """
  
  def __init__(
    self, 
    key,
    byte_order = "big",
    P_array = _PI_P_ARRAY,
    S_boxes = _PI_S_BOXES
  ):
    if not 8 <= len(key) <= 56:
      raise ValueError("key size is not between 8 and 56")
      
    if byte_order == "big":
      byte_order_fmt = ">"
    elif byte_order == "little":
      byte_order_fmt = "<"
    else:
      raise ValueError("byte order must either be 'big' or 'little'")
    self.byte_order = byte_order
    
    # Create Structs
    u4_2_struct = Struct("{}2I".format(byte_order_fmt))
    u4_1_struct = Struct("{}I".format(byte_order_fmt))
    u8_1_struct = Struct("{}Q".format(byte_order_fmt))
    u1_4_struct = Struct("=4B")
    u1_1_struct = Struct("=B")
      
    # Save refs locally to the needed pack/unpack funcs of the structs to speed
    # up look-ups a little.
    self._u4_2_pack = u4_2_struct.pack
    self._u4_2_unpack = u4_2_struct.unpack
    self._u4_2_iter_unpack = u4_2_struct.iter_unpack
    self._u4_1_pack = u4_1_struct.pack
    self._u1_4_unpack = u1_4_struct.unpack
    self._u8_1_pack = u8_1_struct.pack
    self._u1_1_iter_unpack = u1_1_struct.iter_unpack
          
    # Copy P array locally
    P = list(P_array)
    
    # Copy S-boxes locally
    S = list(list(box[0:256]) for box in S_boxes[0:4])

    # Generate subkey P array
    j = 0
    for i in range(len(P)):
      data = 0x00000000
      for _ in range(4):
        data = (data << 8) | key[j % len(key)]
        j = j + 1
      P[i] ^= data
        
    L, R = 0x00000000, 0x00000000
    for i in range(0, len(P), 2):
      L, R = self._cycle(L, R, P, *S)
      P[i], P[i + 1] = L, R
        
    # Generate subkey S-boxes
    for box in S:
      for j in range(0, 256, 2):
        L, R = self._cycle(L, R, P, *S)
        box[j], box[j + 1] = L, R
    
    # Make P array immutable
    self.P = tuple(P)
    
    # Store a reversed copy for decrypting
    self.P_reversed = self.P[::-1]
    
    # Make S-boxes immutable
    self.S = tuple(tuple(s) for s in S)
      
  def _cycle(self, L, R, P, S0, S1, S2, S3):
    return self._cycle_fast(
      L,
      R,
      P, S0, S1, S2, S3,
      self._u1_4_unpack, self._u4_1_pack
    )
    
  def _cycle_fast(self, L, R, P, S0, S1, S2, S3, u1_4_unpack, u4_1_pack):
    for p in P[0:-2]:
      L ^= p
      a, b, c, d = u1_4_unpack(u4_1_pack(L))
      R ^= (((S0[a] + S1[b]) ^ S2[c]) + S3[d]) & 0xffffffff
      L, R = R, L
    return R ^ P[-1], L ^ P[-2]
  
  def _encrypt(self, L, R):
    S0, S1, S2, S3 = self.S
    return self._cycle_fast(
      L,
      R,
      self.P, S0, S1, S2, S3,
      self._u1_4_unpack, self._u4_1_pack
    )
    
  def _decrypt(self, L, R):
    S0, S1, S2, S3 = self.S
    return self._cycle_fast(
      L,
      R,
      self.P_reversed, S0, S1, S2, S3,
      self._u1_4_unpack, self._u4_1_pack
    )
  
  def encrypt_block(self, block):
    """
    Return the encrypted value of a `block`.
    
    `block` should be a :obj:`bytes`-like object with a length of exactly 8
    (i.e. 64 bits).
    If it is not, a :exc:`struct.error` exception is raised.
    """
    return self._u4_2_pack(*self._encrypt(*self._u4_2_unpack(block)))
  
  def decrypt_block(self, block):
    """
    Return the decrypted value of a `block`.
    
    `block` should be a :obj:`bytes`-like object with a length of exactly 8
    (i.e. 64 bits).
    If it is not, a :exc:`struct.error` exception is raised.      
    """
    return self._u4_2_pack(*self._decrypt(*self._u4_2_unpack(block)))
    
  def encrypt_ecb(self, data):
    """
    Return an iterator that encrypts `data` using the Electronic Codebook (ECB)
    mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the encrypted value of the corresponding block in
    `data`.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    for plain_L, plain_R in self._u4_2_iter_unpack(data):
      yield u4_2_pack(
        *cycle_fast(
          plain_L,
          plain_R,
          P, S0, S1, S2, S3,
          u1_4_unpack, u4_1_pack
        )
      )
    
  def decrypt_ecb(self, data):
    """
    Return an iterator that decrypts `data` using the Electronic Codebook (ECB)
    mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the decrypted value of the corresponding block in
    `data`.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P_reversed = self.P_reversed
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    for cipher_L, cipher_R in self._u4_2_iter_unpack(data):
      yield u4_2_pack(
        *cycle_fast(
          cipher_L,
          cipher_R,
          P_reversed,
          S0, S1, S2, S3,
          u1_4_unpack, u4_1_pack
        )
      )
    
  def encrypt_cbc(self, data, init_vector):
    """
    Return an iterator that encrypts `data` using the Cipher-Block Chaining
    (CBC) mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the encrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    prev_cipher_L, prev_cipher_R = self._u4_2_unpack(init_vector)
    
    for plain_L, plain_R in self._u4_2_iter_unpack(data):
      prev_cipher_L, prev_cipher_R = cycle_fast(
        prev_cipher_L ^ plain_L,
        prev_cipher_R ^ plain_R,
        P,
        S0, S1, S2, S3,
        u1_4_unpack,
        u4_1_pack
      )
      yield u4_2_pack(prev_cipher_L, prev_cipher_R)
  
  def decrypt_cbc(self, data, init_vector):
    """
    Return an iterator that decrypts `data` using the Cipher-Block Chaining
    (CBC) mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the decrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P_reversed = self.P_reversed
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    prev_cipher_L, prev_cipher_R = self._u4_2_unpack(init_vector)
    
    for cipher_L, cipher_R in self._u4_2_iter_unpack(data):
      L, R = cycle_fast(
        cipher_L,
        cipher_R,
        P_reversed, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      yield u4_2_pack(prev_cipher_L ^ L, prev_cipher_R ^ R)
      prev_cipher_L, prev_cipher_R = cipher_L, cipher_R
  
  def encrypt_pcbc(self, data, init_vector):
    """
    Return an iterator that encrypts `data` using the Propagating Cipher-Block
    Chaining (PCBC) mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the encrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    init_L, init_R = self._u4_2_unpack(init_vector)
    
    for plain_L, plain_R in self._u4_2_iter_unpack(data):
      cipher_L, cipher_R = cycle_fast(
        init_L ^ plain_L,
        init_R ^ plain_R,
        P,
        S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      yield u4_2_pack(cipher_L, cipher_R)
      init_L, init_R = plain_L ^ cipher_L, plain_R ^ cipher_R
    
  def decrypt_pcbc(self, data, init_vector):
    """
    Return an iterator that decrypts `data` using the Propagating Cipher-Block
    Chaining (PCBC) mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the decrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P_reversed = self.P_reversed
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    init_L, init_R = self._u4_2_unpack(init_vector)
    
    for cipher_L, cipher_R in self._u4_2_iter_unpack(data):
      L, R = cycle_fast(
        cipher_L,
        cipher_R,
        P_reversed, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      plain_L, plain_R = init_L ^ L, init_R ^ R
      yield u4_2_pack(plain_L, plain_R)
      init_L, init_R = cipher_L ^ plain_L, cipher_R ^ plain_R
    
  def encrypt_cfb(self, data, init_vector):
    """
    Return an iterator that encrypts `data` using the Cipher Feedback (CFB)
    mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the encrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    prev_cipher_L, prev_cipher_R = self._u4_2_unpack(init_vector)
    
    for plain_L, plain_R in self._u4_2_iter_unpack(data):
      L, R = cycle_fast(
        prev_cipher_L,
        prev_cipher_R,
        P, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      prev_cipher_L, prev_cipher_R = plain_L ^ L, plain_R ^ R
      yield u4_2_pack(prev_cipher_L, prev_cipher_R)
    
  def decrypt_cfb(self, data, init_vector):
    """
    Return an iterator that decrypts `data` using the Cipher Feedback (CFB)
    mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the decrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    prev_cipher_L, prev_cipher_R = self._u4_2_unpack(init_vector)
    
    for cipher_L, cipher_R in self._u4_2_iter_unpack(data):
      L, R = cycle_fast(
        prev_cipher_L,
        prev_cipher_R,
        P, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      yield u4_2_pack(L ^ cipher_L, R ^ cipher_R)
      prev_cipher_L, prev_cipher_R = cipher_L, cipher_R
    
  def encrypt_ofb(self, data, init_vector):
    """
    Return an iterator that encrypts `data` using the Output Feedback (OFB)
    mode of operation.
    
    Each iteration returns a block sized :obj:`bytes` object (i.e. 8 bytes or
    64 bits) containing the encrypted value of the corresponding block in
    `data`.
    
    `init_vector` is the initialization vector and should be a
    :obj:`bytes`-like object with a length of exactly 8.
    If it is not, a :exc:`struct.error` exception is raised.
    
    `data` should be a :obj:`bytes`-like object with a length of a multiple
    of 8 (i.e. 8, 16, 32, etc.)
    If it is not, a :exc:`struct.error` exception is raised.
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    
    prev_L, prev_R = self._u4_2_unpack(init_vector)
    
    for plain_L, plain_R in self._u4_2_iter_unpack(data):
      prev_L, prev_R = cycle_fast(
        prev_L,
        prev_R,
        P, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      yield u4_2_pack(plain_L ^ prev_L, plain_R ^ prev_R)
    
  def decrypt_ofb(self, data, init_vector):
    """
    Return an iterator that decrypts `data` using the Output Feedback (OFB)
    mode of operation.

    .. note::
        
        In OFB mode, decrypting is the same as encrypting.
        Therefore, calling this function is the same as calling
        :meth:`encrypt_ofb`.
        
    .. seealso::

        :meth:`encrypt_ofb`
     """
    return self.encrypt_ofb(data, init_vector)
      
  def encrypt_ctr(self, data, counter):
    """
    Return an iterator that encrypts `data` using the Counter (CTR) mode of
    operation.
    
    Each iteration, except the last, always returns a block sized :obj:`bytes`
    object (i.e. 8 bytes or 64 bits) containing the encrypted value of the
    corresponding block in `data`. The last iteration may return a :obj:`bytes`
    object with a length less than the block size, since in CTR mode `data`
    does not have to be an exact multiple of the block size.
        
    `counter` should be an iterable sequence of integers which is guaranteed
    not to repeat for a long time.
    You are responsible for using a nonce in the `counter` to make it unique.
    It should be at least as long as `data`, otherwise the returned iterator
    will only encrypt `data` partially, stopping when `counter` is exhausted.
    As Blowfish has a 64 bit block size, the integers must be less than 2**64.
    If they are not a :exc:`struct.error` exception is raised.
    A good default is implemented by :func:`blowfish.ctr_counter`.
    
    `data` should be a :obj:`bytes`-like object (with any length).
    """
    S0, S1, S2, S3 = self.S
    P = self.P
    u4_2_pack = self._u4_2_pack
    u4_2_unpack = self._u4_2_unpack
    cycle_fast = self._cycle_fast
    u1_4_unpack = self._u1_4_unpack
    u4_1_pack = self._u4_1_pack
    u8_1_pack = self._u8_1_pack
    
    extra_bytes = len(data) % 8
    
    for (plain_L, plain_R), counter_n in zip(
      self._u4_2_iter_unpack(data[0:len(data) - extra_bytes]),
      counter
    ):
      counter_L, counter_R = u4_2_unpack(u8_1_pack(counter_n))
      L, R = cycle_fast(
        counter_L,
        counter_R,
        P, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      yield u4_2_pack(plain_L ^ L, plain_R ^ R)
      
    if extra_bytes:
      counter_L, counter_R = u4_2_unpack(u8_1_pack(next(counter)))
      L, R = cycle_fast(
        counter_L,
        counter_R,
        P, S0, S1, S2, S3,
        u1_4_unpack, u4_1_pack
      )
      yield bytes(
        b ^ n for b, (n,) in zip(
          data[-extra_bytes:],
          self._u1_1_iter_unpack(u4_2_pack(L, R))
        )
      )
      
  def decrypt_ctr(self, data, counter):
    """
    Return an iterator that decrypts `data` using the Counter (CTR) mode of
    operation.
    
    .. note::
        
        In CTR mode, decrypting is the same as encrypting.
        Therefore, calling this function is the same as calling
        :meth:`encrypt_ctr`.
        
    .. seealso::
    
        :meth:`encrypt_ctr`
    """
    return self.encrypt_ctr(data, counter)
    
def ctr_counter(nonce, f, start = 0):
  """
  Return an infinite iterator that starts at `start` and iterates over integers
  between 0 to 2^64 - 1, endlessly combining each integer with the `nonce`
  by using function `f` and returning the result.
  
  `nonce` should be an random integer that is used to make the counter unique.
  
  `f` should be a function that takes two integers, the first being the
  `nonce`, and combines the two in a lossless manner (i.e. xor, addition, etc.).
  
  `start` is from where the counter should start. Regardless of where the
  counter starts from, after reaching 2^64 - 1 the counter wraps around to 0.
  """
  for n in range(start, 2**64):
    yield f(nonce, n)
  while True:
    for n in range(0, 2**64):
      yield f(nonce, n)
      
# vim: tabstop=2 expandtab
