fpc/packages/fcl-base/src/blowfish.pp

{
    This file is part of the Free Component Library (FCL)
    Copyright (c) 1999-2000 by the Free Pascal development team

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    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.

 **********************************************************************}
{
  Unit implementing simple blowfish algorithm
}
{$ifdef fpc}
{$mode objfpc}
{$h+}
{$inline on}
{$endif}
unit BlowFish;

interface

uses SysUtils,Classes;

Const
  BFRounds = 16;      { 16 blowfish rounds }

Type
  PBlowFishKey = ^TBlowFishKey;
  TBlowFishKey = array[0..55] of Byte;
  TBFBlock     = array[0..1] of LongInt;     { BlowFish }

type
  TBlowFish = Class(TObject)
  Private
    PBox    : array[0..(BFRounds+1)] of LongInt;
    SBox    : array[0..3, 0..255] of LongInt;
    Function F(x : Cardinal)  : Cardinal;{$ifdef fpc}inline;{$endif}
  Public
    Constructor Create(Key : TBlowFishKey; KeySize : Integer);
    Procedure Encrypt(var Block : TBFBlock);
    Procedure Decrypt(var Block : TBFBlock);
  end;

Type
  EBlowFishError = Class(EStreamError);

  { TBlowFishStream }

  TBlowFishStream = Class(TOwnerStream)
  Private
    FBF     : TBlowFish;
    FData   : TBFBlock;
    FBufpos : Byte;
    FPos    : Int64;
  protected
    function GetPosition: Int64; override;
    procedure InvalidSeek; override;
  Public
    Constructor Create(AKey : TBlowFishKey; AKeySize : Byte; Dest: TStream); overload; virtual;
    Constructor Create(Const KeyPhrase : String; Dest: TStream); overload;
    Destructor Destroy; override;
    Property BlowFish : TBlowFish Read FBF;
  end;

  TBlowFishEncryptStream = Class(TBlowFishStream)
  public
    Destructor Destroy; override;
    function Write(const Buffer; Count: Longint): Longint; override;
    function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
    procedure Flush;
  end;

  TBlowFishDeCryptStream = Class(TBlowFishStream)
  private
    FSourcePos0: Int64;
  public
    Constructor Create(AKey : TBlowFishKey; AKeySize : Byte; Dest: TStream); override;

    function Read(var Buffer; Count: Longint): Longint; override;
    function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
  end;

Implementation

ResourceString
  SNoSeekAllowed  = 'Seek not allowed on encryption streams';
  SErrEmptyPassPhraseNotAllowed = 'Empty passphrase is not allowed in constructor';

{ Blowfish lookup tables }

const
 bf_P: array[0..(BFRounds + 1)] of DWord = (
  $243F6A88, $85A308D3, $13198A2E, $03707344,
  $A4093822, $299F31D0, $082EFA98, $EC4E6C89,
  $452821E6, $38D01377, $BE5466CF, $34E90C6C,
  $C0AC29B7, $C97C50DD, $3F84D5B5, $B5470917,
  $9216D5D9, $8979FB1B);

const
 bf_S: array[0..3, 0..255] of DWord =
(
( $D1310BA6, $98DFB5AC, $2FFD72DB, $D01ADFB7,
  $B8E1AFED, $6A267E96, $BA7C9045, $F12C7F99,
  $24A19947, $B3916CF7, $0801F2E2, $858EFC16,
  $636920D8, $71574E69, $A458FEA3, $F4933D7E,

  $0D95748F, $728EB658, $718BCD58, $82154AEE,
  $7B54A41D, $C25A59B5, $9C30D539, $2AF26013,
  $C5D1B023, $286085F0, $CA417918, $B8DB38EF,
  $8E79DCB0, $603A180E, $6C9E0E8B, $B01E8A3E,

  $D71577C1, $BD314B27, $78AF2FDA, $55605C60,
  $E65525F3, $AA55AB94, $57489862, $63E81440,
  $55CA396A, $2AAB10B6, $B4CC5C34, $1141E8CE,
  $A15486AF, $7C72E993, $B3EE1411, $636FBC2A,

  $2BA9C55D, $741831F6, $CE5C3E16, $9B87931E,
  $AFD6BA33, $6C24CF5C, $7A325381, $28958677,
  $3B8F4898, $6B4BB9AF, $C4BFE81B, $66282193,
  $61D809CC, $FB21A991, $487CAC60, $5DEC8032,

  $EF845D5D, $E98575B1, $DC262302, $EB651B88,
  $23893E81, $D396ACC5, $0F6D6FF3, $83F44239,
  $2E0B4482, $A4842004, $69C8F04A, $9E1F9B5E,
  $21C66842, $F6E96C9A, $670C9C61, $ABD388F0,

  $6A51A0D2, $D8542F68, $960FA728, $AB5133A3,
  $6EEF0B6C, $137A3BE4, $BA3BF050, $7EFB2A98,
  $A1F1651D, $39AF0176, $66CA593E, $82430E88,
  $8CEE8619, $456F9FB4, $7D84A5C3, $3B8B5EBE,

  $E06F75D8, $85C12073, $401A449F, $56C16AA6,
  $4ED3AA62, $363F7706, $1BFEDF72, $429B023D,
  $37D0D724, $D00A1248, $DB0FEAD3, $49F1C09B,
  $075372C9, $80991B7B, $25D479D8, $F6E8DEF7,

  $E3FE501A, $B6794C3B, $976CE0BD, $04C006BA,
  $C1A94FB6, $409F60C4, $5E5C9EC2, $196A2463,
  $68FB6FAF, $3E6C53B5, $1339B2EB, $3B52EC6F,
  $6DFC511F, $9B30952C, $CC814544, $AF5EBD09,

  $BEE3D004, $DE334AFD, $660F2807, $192E4BB3,
  $C0CBA857, $45C8740F, $D20B5F39, $B9D3FBDB,
  $5579C0BD, $1A60320A, $D6A100C6, $402C7279,
  $679F25FE, $FB1FA3CC, $8EA5E9F8, $DB3222F8,

  $3C7516DF, $FD616B15, $2F501EC8, $AD0552AB,
  $323DB5FA, $FD238760, $53317B48, $3E00DF82,
  $9E5C57BB, $CA6F8CA0, $1A87562E, $DF1769DB,
  $D542A8F6, $287EFFC3, $AC6732C6, $8C4F5573,

  $695B27B0, $BBCA58C8, $E1FFA35D, $B8F011A0,
  $10FA3D98, $FD2183B8, $4AFCB56C, $2DD1D35B,
  $9A53E479, $B6F84565, $D28E49BC, $4BFB9790,
  $E1DDF2DA, $A4CB7E33, $62FB1341, $CEE4C6E8,

  $EF20CADA, $36774C01, $D07E9EFE, $2BF11FB4,
  $95DBDA4D, $AE909198, $EAAD8E71, $6B93D5A0,
  $D08ED1D0, $AFC725E0, $8E3C5B2F, $8E7594B7,
  $8FF6E2FB, $F2122B64, $8888B812, $900DF01C,

  $4FAD5EA0, $688FC31C, $D1CFF191, $B3A8C1AD,
  $2F2F2218, $BE0E1777, $EA752DFE, $8B021FA1,
  $E5A0CC0F, $B56F74E8, $18ACF3D6, $CE89E299,
  $B4A84FE0, $FD13E0B7, $7CC43B81, $D2ADA8D9,

  $165FA266, $80957705, $93CC7314, $211A1477,
  $E6AD2065, $77B5FA86, $C75442F5, $FB9D35CF,
  $EBCDAF0C, $7B3E89A0, $D6411BD3, $AE1E7E49,
  $00250E2D, $2071B35E, $226800BB, $57B8E0AF,

  $2464369B, $F009B91E, $5563911D, $59DFA6AA,
  $78C14389, $D95A537F, $207D5BA2, $02E5B9C5,
  $83260376, $6295CFA9, $11C81968, $4E734A41,
  $B3472DCA, $7B14A94A, $1B510052, $9A532915,

  $D60F573F, $BC9BC6E4, $2B60A476, $81E67400,
  $08BA6FB5, $571BE91F, $F296EC6B, $2A0DD915,
  $B6636521, $E7B9F9B6, $FF34052E, $C5855664,
  $53B02D5D, $A99F8FA1, $08BA4799, $6E85076A),
  {SECOND 256}
 ($4B7A70E9, $B5B32944, $DB75092E, $C4192623,
  $AD6EA6B0, $49A7DF7D, $9CEE60B8, $8FEDB266,
  $ECAA8C71, $699A17FF, $5664526C, $C2B19EE1,
  $193602A5, $75094C29, $A0591340, $E4183A3E,

  $3F54989A, $5B429D65, $6B8FE4D6, $99F73FD6,
  $A1D29C07, $EFE830F5, $4D2D38E6, $F0255DC1,
  $4CDD2086, $8470EB26, $6382E9C6, $021ECC5E,
  $09686B3F, $3EBAEFC9, $3C971814, $6B6A70A1,

  $687F3584, $52A0E286, $B79C5305, $AA500737,
  $3E07841C, $7FDEAE5C, $8E7D44EC, $5716F2B8,
  $B03ADA37, $F0500C0D, $F01C1F04, $0200B3FF,
  $AE0CF51A, $3CB574B2, $25837A58, $DC0921BD,

  $D19113F9, $7CA92FF6, $94324773, $22F54701,
  $3AE5E581, $37C2DADC, $C8B57634, $9AF3DDA7,
  $A9446146, $0FD0030E, $ECC8C73E, $A4751E41,
  $E238CD99, $3BEA0E2F, $3280BBA1, $183EB331,

  $4E548B38, $4F6DB908, $6F420D03, $F60A04BF,
  $2CB81290, $24977C79, $5679B072, $BCAF89AF,
  $DE9A771F, $D9930810, $B38BAE12, $DCCF3F2E,
  $5512721F, $2E6B7124, $501ADDE6, $9F84CD87,

  $7A584718, $7408DA17, $BC9F9ABC, $E94B7D8C,
  $EC7AEC3A, $DB851DFA, $63094366, $C464C3D2,
  $EF1C1847, $3215D908, $DD433B37, $24C2BA16,
  $12A14D43, $2A65C451, $50940002, $133AE4DD,

  $71DFF89E, $10314E55, $81AC77D6, $5F11199B,
  $043556F1, $D7A3C76B, $3C11183B, $5924A509,
  $F28FE6ED, $97F1FBFA, $9EBABF2C, $1E153C6E,
  $86E34570, $EAE96FB1, $860E5E0A, $5A3E2AB3,

  $771FE71C, $4E3D06FA, $2965DCB9, $99E71D0F,
  $803E89D6, $5266C825, $2E4CC978, $9C10B36A,
  $C6150EBA, $94E2EA78, $A5FC3C53, $1E0A2DF4,
  $F2F74EA7, $361D2B3D, $1939260F, $19C27960,

  $5223A708, $F71312B6, $EBADFE6E, $EAC31F66,
  $E3BC4595, $A67BC883, $B17F37D1, $018CFF28,
  $C332DDEF, $BE6C5AA5, $65582185, $68AB9802,
  $EECEA50F, $DB2F953B, $2AEF7DAD, $5B6E2F84,

  $1521B628, $29076170, $ECDD4775, $619F1510,
  $13CCA830, $EB61BD96, $0334FE1E, $AA0363CF,
  $B5735C90, $4C70A239, $D59E9E0B, $CBAADE14,
  $EECC86BC, $60622CA7, $9CAB5CAB, $B2F3846E,

  $648B1EAF, $19BDF0CA, $A02369B9, $655ABB50,
  $40685A32, $3C2AB4B3, $319EE9D5, $C021B8F7,
  $9B540B19, $875FA099, $95F7997E, $623D7DA8,
  $F837889A, $97E32D77, $11ED935F, $16681281,

  $0E358829, $C7E61FD6, $96DEDFA1, $7858BA99,
  $57F584A5, $1B227263, $9B83C3FF, $1AC24696,
  $CDB30AEB, $532E3054, $8FD948E4, $6DBC3128,
  $58EBF2EF, $34C6FFEA, $FE28ED61, $EE7C3C73,

  $5D4A14D9, $E864B7E3, $42105D14, $203E13E0,
  $45EEE2B6, $A3AAABEA, $DB6C4F15, $FACB4FD0,
  $C742F442, $EF6ABBB5, $654F3B1D, $41CD2105,
  $D81E799E, $86854DC7, $E44B476A, $3D816250,

  $CF62A1F2, $5B8D2646, $FC8883A0, $C1C7B6A3,
  $7F1524C3, $69CB7492, $47848A0B, $5692B285,
  $095BBF00, $AD19489D, $1462B174, $23820E00,
  $58428D2A, $0C55F5EA, $1DADF43E, $233F7061,

  $3372F092, $8D937E41, $D65FECF1, $6C223BDB,
  $7CDE3759, $CBEE7460, $4085F2A7, $CE77326E,
  $A6078084, $19F8509E, $E8EFD855, $61D99735,
  $A969A7AA, $C50C06C2, $5A04ABFC, $800BCADC,

  $9E447A2E, $C3453484, $FDD56705, $0E1E9EC9,
  $DB73DBD3, $105588CD, $675FDA79, $E3674340,
  $C5C43465, $713E38D8, $3D28F89E, $F16DFF20,
  $153E21E7, $8FB03D4A, $E6E39F2B, $DB83ADF7),
  {THIRD 256}
 ($E93D5A68, $948140F7, $F64C261C, $94692934,
  $411520F7, $7602D4F7, $BCF46B2E, $D4A20068,
  $D4082471, $3320F46A, $43B7D4B7, $500061AF,
  $1E39F62E, $97244546, $14214F74, $BF8B8840,

  $4D95FC1D, $96B591AF, $70F4DDD3, $66A02F45,
  $BFBC09EC, $03BD9785, $7FAC6DD0, $31CB8504,
  $96EB27B3, $55FD3941, $DA2547E6, $ABCA0A9A,
  $28507825, $530429F4, $0A2C86DA, $E9B66DFB,

  $68DC1462, $D7486900, $680EC0A4, $27A18DEE,
  $4F3FFEA2, $E887AD8C, $B58CE006, $7AF4D6B6,
  $AACE1E7C, $D3375FEC, $CE78A399, $406B2A42,
  $20FE9E35, $D9F385B9, $EE39D7AB, $3B124E8B,

  $1DC9FAF7, $4B6D1856, $26A36631, $EAE397B2,
  $3A6EFA74, $DD5B4332, $6841E7F7, $CA7820FB,
  $FB0AF54E, $D8FEB397, $454056AC, $BA489527,
  $55533A3A, $20838D87, $FE6BA9B7, $D096954B,

  $55A867BC, $A1159A58, $CCA92963, $99E1DB33,
  $A62A4A56, $3F3125F9, $5EF47E1C, $9029317C,
  $FDF8E802, $04272F70, $80BB155C, $05282CE3,
  $95C11548, $E4C66D22, $48C1133F, $C70F86DC,

  $07F9C9EE, $41041F0F, $404779A4, $5D886E17,
  $325F51EB, $D59BC0D1, $F2BCC18F, $41113564,
  $257B7834, $602A9C60, $DFF8E8A3, $1F636C1B,
  $0E12B4C2, $02E1329E, $AF664FD1, $CAD18115,

  $6B2395E0, $333E92E1, $3B240B62, $EEBEB922,
  $85B2A20E, $E6BA0D99, $DE720C8C, $2DA2F728,
  $D0127845, $95B794FD, $647D0862, $E7CCF5F0,
  $5449A36F, $877D48FA, $C39DFD27, $F33E8D1E,

  $0A476341, $992EFF74, $3A6F6EAB, $F4F8FD37,
  $A812DC60, $A1EBDDF8, $991BE14C, $DB6E6B0D,
  $C67B5510, $6D672C37, $2765D43B, $DCD0E804,
  $F1290DC7, $CC00FFA3, $B5390F92, $690FED0B,

  $667B9FFB, $CEDB7D9C, $A091CF0B, $D9155EA3,
  $BB132F88, $515BAD24, $7B9479BF, $763BD6EB,
  $37392EB3, $CC115979, $8026E297, $F42E312D,
  $6842ADA7, $C66A2B3B, $12754CCC, $782EF11C,

  $6A124237, $B79251E7, $06A1BBE6, $4BFB6350,
  $1A6B1018, $11CAEDFA, $3D25BDD8, $E2E1C3C9,
  $44421659, $0A121386, $D90CEC6E, $D5ABEA2A,
  $64AF674E, $DA86A85F, $BEBFE988, $64E4C3FE,

  $9DBC8057, $F0F7C086, $60787BF8, $6003604D,
  $D1FD8346, $F6381FB0, $7745AE04, $D736FCCC,
  $83426B33, $F01EAB71, $B0804187, $3C005E5F,
  $77A057BE, $BDE8AE24, $55464299, $BF582E61,

  $4E58F48F, $F2DDFDA2, $F474EF38, $8789BDC2,
  $5366F9C3, $C8B38E74, $B475F255, $46FCD9B9,
  $7AEB2661, $8B1DDF84, $846A0E79, $915F95E2,
  $466E598E, $20B45770, $8CD55591, $C902DE4C,

  $B90BACE1, $BB8205D0, $11A86248, $7574A99E,
  $B77F19B6, $E0A9DC09, $662D09A1, $C4324633,
  $E85A1F02, $09F0BE8C, $4A99A025, $1D6EFE10,
  $1AB93D1D, $0BA5A4DF, $A186F20F, $2868F169,

  $DCB7DA83, $573906FE, $A1E2CE9B, $4FCD7F52,
  $50115E01, $A70683FA, $A002B5C4, $0DE6D027,
  $9AF88C27, $773F8641, $C3604C06, $61A806B5,
  $F0177A28, $C0F586E0, $006058AA, $30DC7D62,

  $11E69ED7, $2338EA63, $53C2DD94, $C2C21634,
  $BBCBEE56, $90BCB6DE, $EBFC7DA1, $CE591D76,
  $6F05E409, $4B7C0188, $39720A3D, $7C927C24,
  $86E3725F, $724D9DB9, $1AC15BB4, $D39EB8FC,

  $ED545578, $08FCA5B5, $D83D7CD3, $4DAD0FC4,
  $1E50EF5E, $B161E6F8, $A28514D9, $6C51133C,
  $6FD5C7E7, $56E14EC4, $362ABFCE, $DDC6C837,
  $D79A3234, $92638212, $670EFA8E, $406000E0),
  {FOURTH 256}
 ($3A39CE37, $D3FAF5CF, $ABC27737, $5AC52D1B,
  $5CB0679E, $4FA33742, $D3822740, $99BC9BBE,
  $D5118E9D, $BF0F7315, $D62D1C7E, $C700C47B,
  $B78C1B6B, $21A19045, $B26EB1BE, $6A366EB4,

  $5748AB2F, $BC946E79, $C6A376D2, $6549C2C8,
  $530FF8EE, $468DDE7D, $D5730A1D, $4CD04DC6,
  $2939BBDB, $A9BA4650, $AC9526E8, $BE5EE304,
  $A1FAD5F0, $6A2D519A, $63EF8CE2, $9A86EE22,

  $C089C2B8, $43242EF6, $A51E03AA, $9CF2D0A4,
  $83C061BA, $9BE96A4D, $8FE51550, $BA645BD6,
  $2826A2F9, $A73A3AE1, $4BA99586, $EF5562E9,
  $C72FEFD3, $F752F7DA, $3F046F69, $77FA0A59,

  $80E4A915, $87B08601, $9B09E6AD, $3B3EE593,
  $E990FD5A, $9E34D797, $2CF0B7D9, $022B8B51,
  $96D5AC3A, $017DA67D, $D1CF3ED6, $7C7D2D28,
  $1F9F25CF, $ADF2B89B, $5AD6B472, $5A88F54C,

  $E029AC71, $E019A5E6, $47B0ACFD, $ED93FA9B,
  $E8D3C48D, $283B57CC, $F8D56629, $79132E28,
  $785F0191, $ED756055, $F7960E44, $E3D35E8C,
  $15056DD4, $88F46DBA, $03A16125, $0564F0BD,

  $C3EB9E15, $3C9057A2, $97271AEC, $A93A072A,
  $1B3F6D9B, $1E6321F5, $F59C66FB, $26DCF319,
  $7533D928, $B155FDF5, $03563482, $8ABA3CBB,
  $28517711, $C20AD9F8, $ABCC5167, $CCAD925F,

  $4DE81751, $3830DC8E, $379D5862, $9320F991,
  $EA7A90C2, $FB3E7BCE, $5121CE64, $774FBE32,
  $A8B6E37E, $C3293D46, $48DE5369, $6413E680,
  $A2AE0810, $DD6DB224, $69852DFD, $09072166,

  $B39A460A, $6445C0DD, $586CDECF, $1C20C8AE,
  $5BBEF7DD, $1B588D40, $CCD2017F, $6BB4E3BB,
  $DDA26A7E, $3A59FF45, $3E350A44, $BCB4CDD5,
  $72EACEA8, $FA6484BB, $8D6612AE, $BF3C6F47,

  $D29BE463, $542F5D9E, $AEC2771B, $F64E6370,
  $740E0D8D, $E75B1357, $F8721671, $AF537D5D,
  $4040CB08, $4EB4E2CC, $34D2466A, $0115AF84,
  $E1B00428, $95983A1D, $06B89FB4, $CE6EA048,

  $6F3F3B82, $3520AB82, $011A1D4B, $277227F8,
  $611560B1, $E7933FDC, $BB3A792B, $344525BD,
  $A08839E1, $51CE794B, $2F32C9B7, $A01FBAC9,
  $E01CC87E, $BCC7D1F6, $CF0111C3, $A1E8AAC7,

  $1A908749, $D44FBD9A, $D0DADECB, $D50ADA38,
  $0339C32A, $C6913667, $8DF9317C, $E0B12B4F,
  $F79E59B7, $43F5BB3A, $F2D519FF, $27D9459C,
  $BF97222C, $15E6FC2A, $0F91FC71, $9B941525,

  $FAE59361, $CEB69CEB, $C2A86459, $12BAA8D1,
  $B6C1075E, $E3056A0C, $10D25065, $CB03A442,
  $E0EC6E0E, $1698DB3B, $4C98A0BE, $3278E964,
  $9F1F9532, $E0D392DF, $D3A0342B, $8971F21E,

  $1B0A7441, $4BA3348C, $C5BE7120, $C37632D8,
  $DF359F8D, $9B992F2E, $E60B6F47, $0FE3F11D,
  $E54CDA54, $1EDAD891, $CE6279CF, $CD3E7E6F,
  $1618B166, $FD2C1D05, $848FD2C5, $F6FB2299,

  $F523F357, $A6327623, $93A83531, $56CCCD02,
  $ACF08162, $5A75EBB5, $6E163697, $88D273CC,
  $DE966292, $81B949D0, $4C50901B, $71C65614,
  $E6C6C7BD, $327A140A, $45E1D006, $C3F27B9A,

  $C9AA53FD, $62A80F00, $BB25BFE2, $35BDD2F6,
  $71126905, $B2040222, $B6CBCF7C, $CD769C2B,
  $53113EC0, $1640E3D3, $38ABBD60, $2547ADF0,
  $BA38209C, $F746CE76, $77AFA1C5, $20756060,

  $85CBFE4E, $8AE88DD8, $7AAAF9B0, $4CF9AA7E,
  $1948C25C, $02FB8A8C, $01C36AE4, $D6EBE1F9,
  $90D4F869, $A65CDEA0, $3F09252D, $C208E69F,
  $B74E6132, $CE77E25B, $578FDFE3, $3AC372E6)
);


Constructor TBlowFish.Create(Key : TBlowFishKey; KeySize : Integer);

var
  I     : Integer;
  J     : Integer;
  K     : Integer;
  Data  : Cardinal;
  Block : TBFBlock;

begin
  Move(bf_P, PBox, SizeOf(PBox));
  Move(bf_S, SBox, SizeOf(SBox));

  { update PArray with the key bits }
  J := 0;
  for I := 0 to (BFRounds+1) do begin
    Data := 0;
    for K := 0 to 3 do begin
      Data := (Data shl 8) or Key[J];
      Inc(J);
      if J >= KeySize then
        J := 0;
    end;
    PBox[I] := PBox[I] xor Data;
  end;

  { Encrypt all-zero block}
  Block[0] := 0;
  Block[1] := 0;
  I := 0;
  repeat
    Encrypt(Block);
    PBox[I] := Block[0];
    PBox[I+1] := Block[1];
    Inc(I, 2);
  until I > BFRounds+1;

  { Now continue with rest }
  for J := 0 to 3 do begin
    I := 0;
    repeat
      Encrypt(Block);
      SBox[J, I] := Block[0];
      SBox[J, I+1] := Block[1];
      Inc(I, 2);
    until I > 255;
  end;
end;

Function TBlowFish.F(x : Cardinal)  : Cardinal;{$ifdef fpc}inline;{$endif}

var
  a, b, c, d : Byte;
  y : cardinal;

begin
  d:=x and $FF;
  x:=x shr 8;
  c:=x and $FF;
  x:=x shr 8;
  b:=x and $FF;
  x:=x shr 8;
  a:= x and $FF;
  Result:=Sbox[0][a]+Sbox[1][b];
  Result:=Result xor Sbox[2][c];
  Result:=Result + Sbox[3][d];
end;

procedure TBlowFish.Encrypt(var Block : TBFBlock);
var
  I : Integer;
  xl,xr,temp : Cardinal;
begin
  Xl:= block[0];
  Xr:= block[1];
  for i:=0 to 15 do
    begin
    Xl:=Xl xor Pbox[i];
    Xr:= F(Xl) xor Xr;
    temp:= Xl;
    Xl:= Xr;
    Xr := temp;
    end;
  temp := Xl;
  Xl := Xr;
  Xr := temp;
  Xr := Xr xor Pbox[16];
  Xl := Xl xor Pbox[17];
  Block[0]:=Xl;
  Block[1]:=Xr;
end;

procedure TBlowFish.Decrypt(var Block : TBFBlock);
var
  I : Integer;
  xl,xr,temp : Cardinal;
begin
    Xl:= block[0];
    Xr:= block[1];
    for i:=17 downto 2 do
      begin
      Xl := Xl xor PBox[i];
      Xr := F(Xl) xor Xr;
      temp := Xl;
      Xl := Xr;
      Xr := temp;
      end;

    temp := Xl;
    Xl := Xr;
    Xr := temp;
    Xr := Xr xor Pbox[1];
    Xl := Xl xor Pbox[0];
    Block[0]:=Xl;
    Block[1]:=Xr;
end;

{ ---------------------------------------------------------------------
    TBlowFishStream
  ---------------------------------------------------------------------}

function TBlowFishStream.GetPosition: Int64;
begin
  Result:=FPos;
end;

procedure TBlowFishStream.InvalidSeek;
begin
  raise EBlowFishError.Create(SNoSeekAllowed);
end;

Constructor TBlowFishStream.Create(AKey : TBlowFishkey; AKeySize : Byte; Dest: TStream);

begin
  inherited Create(Dest);
  FBF:=TBlowFish.Create(AKey,AKeySize);
  FBufPos:=0;
  FPos:=0;
end;

constructor TBlowFishStream.Create(const KeyPhrase: String; Dest: TStream);

Var
  KLen : Integer;
  K : TBlowFishKey;

begin
  If (KeyPhrase='') then
    Raise EBlowFishError.Create(SErrEmptyPassPhraseNotAllowed);
  KLen:=Length(KeyPhrase);
  If KLen>56 then
    KLen:=56;
  Move(KeyPhrase[1],K,Klen);
  Create(K,KLen,Dest);
end;

Destructor TBlowFishStream.Destroy;

begin
  FreeAndNil(FBF);
  Inherited;
end;

{ ---------------------------------------------------------------------
    TBlowFishEncryptStream
  ---------------------------------------------------------------------}

Destructor TBlowFishEncryptStream.Destroy;


begin
  Flush;
  Inherited Destroy;
end;

Procedure TBlowFishEncryptStream.Flush;

begin
  If FBufPos>0 then
    begin
    // Fill with nulls
    FillChar(PChar(@FData)[FBufPos],SizeOf(FData)-FBufPos,#0);
    FBF.EnCrypt(FData);
    Source.Write(FData,SizeOf(FData));
    FBufPos := 0;
    end;
end;

function TBlowFishEncryptStream.Write(const Buffer; Count: Longint): Longint;

Var
  mvsize : Longint;

begin
  Result:=0;
  While Count>0 do
    begin
    MVsize:=Count;
    If Mvsize>SizeOf(Fdata)-FBufPos then
      mvsize:=SizeOf(FData)-FBufPos;
    Move(PChar(@Buffer)[Result],PChar(@FData)[FBufPos],MVSize);
    If FBufPos+mvSize=Sizeof(FData) then
      begin
      // Empty buffer.
      FBF.Encrypt(FData);
      // this will raise an exception if needed.
      Source.Writebuffer(FData,SizeOf(FData));
      FBufPos:=0;
      end
    else
      inc(FBufPos,mvsize);
    Dec(Count,MvSize);
    Inc(Result,mvSize);
    end;
  Inc(FPos,Result);
end;


function TBlowFishEncryptStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;

begin
  if (Offset = 0) and (Origin = soCurrent) then
    Result := FPos
  else
    InvalidSeek;
end;


{ ---------------------------------------------------------------------
    TBlowFishDecryptStream
  ---------------------------------------------------------------------}

constructor TBlowFishDeCryptStream.Create(AKey: TBlowFishKey; AKeySize: Byte;
  Dest: TStream);
begin
  inherited Create(AKey, AKeySize, Dest);

  FSourcePos0 := Source.Position;
end;

function TBlowFishDeCryptStream.Read(var Buffer; Count: Longint): Longint;

Var
  mvsize : Longint;

begin
  Result:=0;
  While Count>0 do
    begin
    // Empty existing buffer.
    If (FBufPos>0) then
      begin
      mvSize:=FBufPos;
      If MvSize>count then
        mvsize:=Count;
      Move(PChar(@FData)[0],PChar(@Buffer)[Result],MVSize);
      If ((Sizeof(FData)-MvSize)>0) then
        Move(PChar(@FData)[mvSize],PChar(@FData)[0],Sizeof(FData)-MvSize);
      Dec(Count,mvsize);
      Inc(Result,mvsize);
      FBufPos:=FBufPos-MvSize;
      end;
    // Fill buffer again if needed.
    If  (Count>0) then
      Begin
      mvsize:=Source.Read(FData,SizeOf(FData));
      If mvsize>0 then
        begin
        If MvSize<SizeOf(FData) Then
          // Fill with nulls
          FillChar(PChar(@FData)[mvsize],SizeOf(FData)-mvsize,#0);
        FBF.Decrypt(FData);
        FBufPos:=SizeOf(FData);
        end
      else
        Count:=0; // No more data available from stream; st
      end;
    end;
  Inc(FPos,Result);
end;

function TBlowFishDeCryptStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;

begin
  if (Offset=0) and (Origin=soBeginning) then
  begin // support seek to beginning
    FBufPos:=0;
    FPos:=0;
    Source.Position := FSourcePos0;
  end else
    FakeSeekForward(Offset,TSeekOrigin(Origin),FPos);
  Result:=FPos;
end;

end.