HPAVC/HPAVC CD-ROM.iso/pc/ZIPCRK10.ZIP/ZIPCRACK.PAS

Pascal/Delphi Source File | 1993-03-17 | 20.1 KB | 684 lines

program zipcrack;

{$M 16384, 0, 65536}

{-----------------------------------------------------------------------}
{                                                                        }
{ Program ZIPCRACK Copyright 1993 by Michael A. Quinlan                    }
{                                                                        }
{ Brute force attack on PKZIP V2 encryption.                            }
{ Based on the APPNOTE.TXT distributed with the registered version        }
{ of PKZIP 2.04g.                                                        }
{                                                                        }
{ Method: Generate all possible passwords; invoke PKUNZIP -t (test)        }
{ option to test each password.                                            }
{                                                                        }
{ Input: Minimum and maximum password lengths, password character set,    }
{ Zipfile name, name of file to extract.                                }
{                                                                        }
{ Options: Interval to save last password attempted; this allows the    }
{ program to be restarted.                                                }
{                                                                        }
{ Performance improvements: placing PKUNZIP and the Zipfile on a RAM    }
{ disk will improve speed. Increasing the 'save' interval will also        }
{ increase speed. Making the current directory a RAM disk is _NOT_        }
{ recommended, since a crash (power hit, etc.) will lose the saved        }
{ 'last password' and you will have to restart from scratch.            }
{                                                                        }
{-----------------------------------------------------------------------}

uses
    DOS,
    CRT;

const
    SaveFN        = 'ZIPCRACK.$$$';        { Save file name                }
    WorkDir        = '\ZIPCRACK';            { Work Subdirectory                }
    MAXPW        = 256;                    { Max Password Length            }
    MAXBUF        = 32768;                { Max buffer length                }
    K0             = 305419896;            { Zipfile Encryption Initializer}
    K1             = 591751049;            { Zipfile Encryption Initializer}
    K2             = 878082192;            { Zipfile Encryption Initializer}
    ZIPHDRSIG    = $04034B50;            { Zip Local Header Signature    }
    ZDHDRSIG    = $02014B50;            { Zip Directory Header Signature}
    ZDENDSIG    = $06054B50;            { Zip Directory End Signature    }

const
    CrcTab : array [0..255] of LongInt =
        (
            $00000000, $77073096, $EE0E612C, $990951BA,
            $076DC419, $706AF48F, $E963A535, $9E6495A3,
            $0EDB8832, $79DCB8A4, $E0D5E91E, $97D2D988,
            $09B64C2B, $7EB17CBD, $E7B82D07, $90BF1D91,
            $1DB71064, $6AB020F2, $F3B97148, $84BE41DE,
            $1ADAD47D, $6DDDE4EB, $F4D4B551, $83D385C7,
            $136C9856, $646BA8C0, $FD62F97A, $8A65C9EC,
            $14015C4F, $63066CD9, $FA0F3D63, $8D080DF5,
            $3B6E20C8, $4C69105E, $D56041E4, $A2677172,
            $3C03E4D1, $4B04D447, $D20D85FD, $A50AB56B,
            $35B5A8FA, $42B2986C, $DBBBC9D6, $ACBCF940,
            $32D86CE3, $45DF5C75, $DCD60DCF, $ABD13D59,
            $26D930AC, $51DE003A, $C8D75180, $BFD06116,
            $21B4F4B5, $56B3C423, $CFBA9599, $B8BDA50F,
            $2802B89E, $5F058808, $C60CD9B2, $B10BE924,
            $2F6F7C87, $58684C11, $C1611DAB, $B6662D3D,
            $76DC4190, $01DB7106, $98D220BC, $EFD5102A,
            $71B18589, $06B6B51F, $9FBFE4A5, $E8B8D433,
            $7807C9A2, $0F00F934, $9609A88E, $E10E9818,
            $7F6A0DBB, $086D3D2D, $91646C97, $E6635C01,
            $6B6B51F4, $1C6C6162, $856530D8, $F262004E,
            $6C0695ED, $1B01A57B, $8208F4C1, $F50FC457,
            $65B0D9C6, $12B7E950, $8BBEB8EA, $FCB9887C,
            $62DD1DDF, $15DA2D49, $8CD37CF3, $FBD44C65,
            $4DB26158, $3AB551CE, $A3BC0074, $D4BB30E2,
            $4ADFA541, $3DD895D7, $A4D1C46D, $D3D6F4FB,
            $4369E96A, $346ED9FC, $AD678846, $DA60B8D0,
            $44042D73, $33031DE5, $AA0A4C5F, $DD0D7CC9,
            $5005713C, $270241AA, $BE0B1010, $C90C2086,
            $5768B525, $206F85B3, $B966D409, $CE61E49F,
            $5EDEF90E, $29D9C998, $B0D09822, $C7D7A8B4,
            $59B33D17, $2EB40D81, $B7BD5C3B, $C0BA6CAD,
            $EDB88320, $9ABFB3B6, $03B6E20C, $74B1D29A,
            $EAD54739, $9DD277AF, $04DB2615, $73DC1683,
            $E3630B12, $94643B84, $0D6D6A3E, $7A6A5AA8,
            $E40ECF0B, $9309FF9D, $0A00AE27, $7D079EB1,
            $F00F9344, $8708A3D2, $1E01F268, $6906C2FE,
            $F762575D, $806567CB, $196C3671, $6E6B06E7,
            $FED41B76, $89D32BE0, $10DA7A5A, $67DD4ACC,
            $F9B9DF6F, $8EBEEFF9, $17B7BE43, $60B08ED5,
            $D6D6A3E8, $A1D1937E, $38D8C2C4, $4FDFF252,
            $D1BB67F1, $A6BC5767, $3FB506DD, $48B2364B,
            $D80D2BDA, $AF0A1B4C, $36034AF6, $41047A60,
            $DF60EFC3, $A867DF55, $316E8EEF, $4669BE79,
            $CB61B38C, $BC66831A, $256FD2A0, $5268E236,
            $CC0C7795, $BB0B4703, $220216B9, $5505262F,
            $C5BA3BBE, $B2BD0B28, $2BB45A92, $5CB36A04,
            $C2D7FFA7, $B5D0CF31, $2CD99E8B, $5BDEAE1D,
            $9B64C2B0, $EC63F226, $756AA39C, $026D930A,
            $9C0906A9, $EB0E363F, $72076785, $05005713,
            $95BF4A82, $E2B87A14, $7BB12BAE, $0CB61B38,
            $92D28E9B, $E5D5BE0D, $7CDCEFB7, $0BDBDF21,
            $86D3D2D4, $F1D4E242, $68DDB3F8, $1FDA836E,
            $81BE16CD, $F6B9265B, $6FB077E1, $18B74777,
            $88085AE6, $FF0F6A70, $66063BCA, $11010B5C,
            $8F659EFF, $F862AE69, $616BFFD3, $166CCF45,
            $A00AE278, $D70DD2EE, $4E048354, $3903B3C2,
            $A7672661, $D06016F7, $4969474D, $3E6E77DB,
            $AED16A4A, $D9D65ADC, $40DF0B66, $37D83BF0,
            $A9BCAE53, $DEBB9EC5, $47B2CF7F, $30B5FFE9,
            $BDBDF21C, $CABAC28A, $53B39330, $24B4A3A6,
            $BAD03605, $CDD70693, $54DE5729, $23D967BF,
            $B3667A2E, $C4614AB8, $5D681B02, $2A6F2B94,
            $B40BBE37, $C30C8EA1, $5A05DF1B, $2D02EF8D
        );

type
    CopyBufT    = array [1..MAXBUF] of char;{ Copy Buffer                }
    CopyBufTP    = ^COpyBufT;                { Ptr to Copy Buffer        }
    Buf12T      = array [0..11] of Char;    { 12-byte buffer            }
    SetOfCharT    = Set of Char;                { Set of characters            }
    CharArrayT    = Array [0..255] of Char;    { List of characters        }
    CharSetT    = record                    { Character Set for Zip PW    }
                    n : 0..256;                { ..# of chars in the set    }
                    c : CharArrayT;            { ..List of PW chars        }
                    s : SetOfCharT;            { ..PW chars in set format    }
                  end;
    ZipHdrT     = record                    { Zip File Header            }
                    Sig        : LongInt;        { ..Signature                }
                    VerReqd    : Word;            { ..Version reqd to unzip    }
                    BitFlag    : Word;            { ..Bit Flag                }
                    Method    : Word;            { ..Compress Method            }
                    LModTime: Word;            { ..Last Mod Time            }
                    LModDate: Word;            { ..Last Mod Date            }
                    CRC32    : LongInt;        { ..File CRC                }
                    CmpSize : LongInt;        { ..Compressed Size            }
                    UncmpSz    : LongInt;        { ..Uncompressed Size        }
                    FNLen    : Word;            { ..File Name Length        }
                    EFLen    : Word;            { ..Extra Field Length        }
                  end;
    ZDHdrT        = Record                    { Directory File Header        }
                    Sig        : LongInt;        { ..Signature                }
                    Version    : Word;            { ..Version made by            }
                    VerReqd    : Word;            { ..Version reqd to extract    }
                    BitFlag    : Word;            { ..Bit Flag                }
                    Method    : Word;            { ..Compression Method        }
                    LModTime: Word;            { ..Last Mod time            }
                    LModDate: Word;            { ..Last Mod Date            }
                    CRC32    : LongInt;        { ..CRC or 0                }
                    CmpSize    : LongInt;        { ..Compressed Size            }
                    UncmpSz    : LongInt;        { ..Uncompressed Size        }
                    FNLen    : Word;            { ..File Name Length        }
                    EFLen    : Word;            { ..Extra Field Length        }
                    FCLen    : Word;            { ..File Comment Length        }
                    DiskNo    : Word;            { ..Starting Disk Number    }
                    IFAttr    : Word;            { ..Internal File Attributes}
                    EFAttr    : LongInt;        { ..External File Attributes}
                    LHOff    : LongInt;        { ..Offset of local header    }
                  end;
    ZDEndT         = Record                    { Directory End Record        }
                    Sig        : LongInt;        { ..Signature                }
                    DiskNo    : Word;            { ..Number of this disk        }
                    ZDDisk    : Word;            { ..Disk w/ start of dir    }
                    ZDETD    : Word;            { ..Dir ents this disk        }
                    ZDEnts    : Word;            { ..Total dir ents            }
                    ZDSize    : LongInt;        { ..Dir size                }
                    ZDStart    : LongInt;        { ..Offset to start of Dir    }
                    CmtLen    : Word;            { ..Zip Comment Length        }
                  end;

var    PkunzipPath : String;                { Path & File name for PKUNZIP    }
    ZipfilePath    : String;                { Path & File name for Zipfile    }
    ZipfileName    : String;                { File name for Zipfile            }
    RamPath        : String;                { Path on RAM Drive                }
    MemberName    : String;                { Zipfile Member Name            }
    MinPWLen    : Integer;                { Minimum password length        }
    MaxPWLen    : Integer;                { Maximum password length        }
    PWCharSet    : CharSetT;                { Password character set        }
    PWSaveInt    : LongInt;                { Password Save Interval        }
    UseRamDisk    : Boolean;                { Use RAM Disk?                    }
    RamDrive    : Char;                    { Ram Disk Drive Letter            }
    NextPW        : array [1..MAXPW] of Byte;{ Next password to try        }
    rc             : Integer;
    PWLen        : Integer;
    PW            : String;
    Key0        : LongInt;                { Zip Encryption Key 0            }
    Key1        : LongInt;                { Zip Encryption Key 1            }
    Key2        : LongInt;                { Zip Encryption Key 2            }
    ZipBuf        : Buf12T;                { Zip Encryption Buffer            }
    ZipFile        : File;
    ZDEnd        : ZDEndT;                { Zip Directory End Record        }
    ZDHdr        : ZDHdrT;                { Zip Directory Header Record    }
    ZipHdr        : ZipHdrT;                { Zip Local Header Record        }
    Ok            : Boolean;


function crc32(crc : LongInt; c : Char) : LongInt;
begin
    crc32 := ((crc shr 8) and $00FFFFFF) xor CrcTab[(Ord(c) xor (crc and $00FF))  and $00FF];
end;

procedure ZipPWUpdateKeys(C : Char);
begin
    Key0 := crc32(Key0, C);
    Key1 := Key1 + (Key0 and $000000FF);
    Key1 := Key1 * 134775813 + 1;
    Key2 := crc32(Key2, Chr((Key1 shr 24) and $000000FF));
end;

function ZipPWDecryptByte : Char;
var Temp : Word;
begin
    Temp := (Key2 or 2) and $0000FFFF;
    ZipPWDecryptByte := Chr(((Temp * (Temp xor 1)) shr 8) and $00FF);
end;

procedure ZipPWInitKeys(PW : String);
var n : Integer;
begin
    Key0 := K0;
    Key1 := K1;
    Key2 := K2;
    for n := 1 to Length(PW) do ZipPWUpdateKeys(PW[n]);
end;

procedure ZipPWUpdateBuf(var Buf : Buf12T);
var i : Integer;
    c : Char;
begin
    for i := 0 to 11 do begin
        c := Chr(Ord(Buf[i]) xor Ord(ZipPWDecryptByte));
        ZipPWUpdateKeys(c);
        Buf[i] := c;
    end;
end;

function ZipPWCheck(PW : String; Buf : Buf12T; crc : LongInt) : Boolean;
begin
    ZipPWInitKeys(PW);
    ZipPWUpdateBuf(Buf);
    ZipPWCheck := Ord(Buf[11]) = ((crc shr 24) and $000000FF);
end;

function ZipOpen(var F : File; Name : String; var ZDEnd : ZDEndT) : Boolean;
var FMSave     : Word;
    SeekPos    : LongInt;
begin
    if Pos('.', Name) = 0 then Name := Name + '.ZIP';
    Assign(F, Name);
    FMSave := FileMode;
    FileMode := 0;
    {$I-} Reset(F, 1); {$I+}
    FileMode := FMSave;
    if IOResult <> 0 then begin
         WriteLn(Name, ': Cannot open file');
        ZipOpen := FALSE;
        Exit;
    end;
    SeekPos := FileSize(F) - sizeof(ZDEnd) + 1;
    while TRUE do begin
        if SeekPos <= 0 then begin
            WriteLn(Name, ': Cannot find ZIP Directory');
            Close(F);
            ZipOpen := FALSE;
            Exit;
        end;
        Dec(SeekPos);
        Seek(F, SeekPos);
        BlockRead(F, ZDEnd, sizeof(ZDEnd));
        if ZDEnd.Sig = ZDENDSIG then begin
            ZipOpen := TRUE;
            Exit;
        end;
    end;
end;

function ZipFindZDHdr(var F : File; Name : String; var ZDEnd : ZDEndT; var ZDHdr : ZDHdrT) : Boolean;
var n        : Word;
    SeekPos    : LongInt;
    Buf        : String;
    FNLen    : Integer;
    i        : Integer;
begin
    FNLen := Length(Name);
    Buf[0] := Chr(FNLen);
    for i := 1 to FNLen do Name[i] := UpCase(Name[i]);
    SeekPos := ZDEnd.ZDStart;
    for n := 1 to ZDEnd.ZDEnts do begin
        Seek(F, SeekPos);
        BlockRead(F, ZDHdr, sizeof(ZDHdr));
        if ZDHdr.FNLen = FNLen then begin
            BlockRead(F, Buf[1], FNLen);
            for i := 1 to FNLen do Buf[i] := UpCase(Buf[i]);
            if Name = Buf then begin
                ZipFindZDHdr := TRUE;
                Exit;
            end;
        end;
        SeekPos := SeekPos + sizeof(ZDHdr) + ZDHdr.FNLen + ZDHdr.EFLen + ZDHdr.FCLen;
    end;
    ZipFindZDHdr := FALSE;
end;

function ZipFindFile(var F : File; Name : String; var ZDEnd : ZDEndT; var ZDHdr : ZDHdrT; var ZipHdr : ZipHdrT) : Boolean;
var Ok : Boolean;
begin
    Ok := ZipFindZDHdr(F, Name, ZDEnd, ZDHdr);
    if not Ok then begin
        ZipFindFile := FALSE;
        Exit;
    end;
    Seek(F, ZDHdr.LHOff);
    BlockRead(F, ZipHdr, sizeof(ZipHdr));
    Seek(F, ZDHdr.LHOff + sizeof(ZipHdr) + ZipHdr.FNLen + ZipHdr.EFLen);
    ZipFindFile := TRUE;
end;

procedure AddCharToCharSet(var SC : CharSetT; c : Char);
begin
    if SC.n = 0 then SC.s := [];
    if not (c in SC.s) then begin
        SC.c[SC.n] := c;
        SC.s := SC.s + [c];
        inc(SC.n);
    end;
end;

procedure AddStringToCharSet(var SC : CharSetT; S : String);
var n : Integer;
begin
    for n := 1 to length(S) do AddCharToCharSet(SC, S[n]);
end;

procedure AddSetToCharSet(var SC : CharSetT; S : SetOfCharT);
var n : Integer;
begin
    for n := 0 to 255 do begin
        if Chr(n) in S then AddCharToCharSet(SC, Chr(n));
    end;
end;

function PromptChar(p : String; r : String) : Char;
var K     : Char;
    S     : String;
    Done : Boolean;
begin
    Done := FALSE;
    while not Done do begin
        Write(p, '? ');
        ReadLn(S);
        if length(s) = 0 then K := #$00
        else K := S[1];
        if Pos(K, r) <> 0 then Done := TRUE
        else WriteLn('Enter one of: ', r);
    end;
    PromptChar := K;
end;

function PromptString(p : String) : String;
var S : String;
begin
    Write(p, '? ');
    ReadLn(S);
    PromptString := S;
end;

function PromptNumber(p : String; Min, Max : LongInt) : LongInt;
var S     : String;
    Code : Integer;
    R     : LongInt;
    Done : Boolean;
begin
    Done := FALSE;
    while not Done do begin
        S := PromptString(p);
        val(S, R, Code);
        if (Code <> 0) or (R < Min) or (R > Max) then
            WriteLn('Enter an integer from ', Min, ' to ', Max)
        else Done := TRUE;
    end;
    PromptNumber := R;
end;

procedure PromptCharSet(p : String; var SC : CharSetT);
var K     : Char;
begin
    SC.n := 0;
    WriteLn(p, ':');
    K := PromptChar('  Lower case letters [a..z]', 'YyNn');
    if UpCase(K) = 'Y' then AddSetToCharSet(SC, ['a'..'z']);
    K := PromptChar('  Upper case letters [A..Z]', 'YyNn');
    if UpCase(K) = 'Y' then AddSetToCharSet(SC, ['A'..'Z']);
    K := PromptChar('  Digits [0..9]', 'YyNn');
    if UpCase(K) = 'Y' then AddSetToCharSet(SC, ['0'..'9']);
    K := PromptChar('  Blank', 'YyNn');
    if UpCase(K) = 'Y' then AddStringToCharSet(SC, ' ');
    K := PromptChar('  Punctuation and special characters', 'YyNn');
    if UpCase(K) = 'Y' then AddStringToCharSet(SC, '`~!@#$%^&*()_-+=[{]}\|;:",<.>/?''');
end;

function PromptFilename(p : String; ext : String; path : String) : String;
var fn     : String;
    fn2     : String;
    Done : Boolean;
    i     : Integer;
begin
    Done := FALSE;
    while not DONE do begin
        fn := PromptString(p);
        if pos('.', fn) = 0 then fn := fn + '.' + ext;
        for i:=1 to length(fn) do fn[i] := UpCase(fn[i]);
        fn2 := FSearch(fn, path);
        if fn2 = '' then WriteLn('Unable to locate ', fn)
        else Done := TRUE;
    end;
    fn := FExpand(fn2);
    for i:=1 to length(fn) do fn[i] := UpCase(fn[i]);
    PromptFilename := fn;
end;

function GetRestartData : Boolean;
var Key      : Char;
    SaveF : File;
begin
    FillChar(NextPW, MAXPW, 0);
    MinPWLen := 0;
    MaxPWLen := 0;
    PWCharSet.n := 0;
    PWLen := 0;
    GetRestartData := FALSE;
    if (FSearch(SaveFN, '') <> '') then begin
        Key := PromptChar('Restart from last password', 'YyNn');
        if upcase(Key) = 'Y' then begin
            Assign(SaveF, SaveFN);
            FileMode := 0;
            Reset(SaveF, 1);
            FileMode := 2;
            BlockRead(SaveF, MinPWLen,  sizeof(MinPWLen));
            BlockRead(SaveF, MaxPWLen,  sizeof(MaxPWLen));
            BlockRead(SaveF, PWCharSet, sizeof(PWCharSet));
            BlockRead(SaveF, PWLen,     sizeof(PWLen));
            BlockRead(SaveF, NextPW,    sizeof(NextPW));
            Close(SaveF);
            GetRestartData := TRUE;
        end;
    end;
end;

function ExecPkunzip(cmdline : String) : Integer;
begin
    SwapVectors;
    Exec(PkunzipPath, cmdline);
    SwapVectors;
    if DosError <> 0 then begin
        WriteLn('DOS Error ', DosError, ' executing ', PkunzipPath);
        Halt(3);
    end;
    ExecPkunzip := DosExitCode;
end;

procedure GetInput;
var Key     : Char;
    D     : DirStr;
    N     : NameStr;
    E     : ExtStr;
    Done : Boolean;
    rc     : Integer;
begin
    if not GetRestartData then begin
        MinPWLen := PromptNumber('Minimum password length', 1, MAXPW);
        if MinPWLen = MAXPW then MaxPWLen := MAXPW
        else MaxPWLen := PromptNumber('Maximum password length', MinPWLen, MAXPW);
        PromptCharSet('Password character set', PWCharSet);
        if PWCharSet.n = 0 then begin
            WriteLn('No characters in password character set!');
            Halt(3);
        end;
    end;
    PWSaveInt := PromptNumber('Password save interval', 0, 1000000);
    Key := PromptChar('Use RAM Disk', 'YyNn');
    if UpCase(Key) <> 'Y' then UseRamDisk := FALSE
    else begin
        UseRamDisk := TRUE;
        Key := PromptChar('RAM Disk drive letter', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ');
        RamDrive := UpCase(Key);
        RamPath := RamDrive + ':' + WorkDir;
    end;

    PkunzipPath := FSearch('PKUNZIP.EXE', GetEnv('PATH'));
    if PkunzipPath <> '' then PkunzipPath := FExpand(PkunzipPath)
    else PkunzipPath := PromptFilename('PKUNZIP file name', 'EXE', GetEnv('PATH'));

    ZipfilePath := PromptFilename('Zip file name', 'ZIP', '');
    FSplit(ZipfilePath, D, N, E);
    ZipfileName := N + E;
    Done := FALSE;
    while not Done do begin
        MemberName := PromptString('File to crack');
        rc := ExecPkunzip('-# -v ' + ZipfilePath + ' ' + MemberName);
        if rc <> 0 then WriteLn('Unable to locate ', MemberName, ' in ', ZipfilePath)
        else Done := TRUE;
    end;
end;

function CopyFile(FromFile, ToFile : String) : Boolean;
var pBuf     : CopyBufTP;
    FromF    : File;
    ToF         : File;
    Count     : Word;
    Written     : Word;
begin
    {$I-}
    Assign(FromF, FromFile);
    FileMode := 0;
    Reset(FromF, 1);
    FileMode := 2;
    if IOResult <> 0 then begin
        CopyFile := FALSE;
        Exit;
    end;
    Assign(ToF, ToFile);
    Rewrite(ToF, 1);
    if IOResult <> 0 then begin
        Close(FromF);
        CopyFile := FALSE;
        Exit;
    end;
    {$I+}
    New(pBuf);
    repeat
        BlockRead(FromF, pBuf^, MAXBUF, Count);
        BlockWrite(ToF, pBuf^, Count, Written);
        if Written <> Count then begin
            Close(FromF);
            Close(ToF);
            CopyFile := FALSE;
            Dispose(pBuf);
            Exit;
        end;
    until Count = 0;
    Dispose(pBuf);
    Close(FromF);
    Close(ToF);
    CopyFile := TRUE;
end;

procedure SavePW;
var SaveF : File;
begin
    Assign(SaveF, SaveFN);
    Rewrite(SaveF, 1);
    BlockWrite(SaveF, MinPWLen,  sizeof(MinPWLen));
    BlockWrite(SaveF, MaxPWLen,  sizeof(MaxPWLen));
    BlockWrite(SaveF, PWCharSet, sizeof(PWCharSet));
    BlockWrite(SaveF, PWLen,     sizeof(PWLen));
    BlockWrite(SaveF, NextPW,    sizeof(NextPW));
    Close(SaveF);
end;

function IncPW : Boolean;
var n : Integer;
begin
    n := PWLen;
    while TRUE do begin
        if n = 0 then begin
            IncPW := FALSE;
            Exit;
        end;
        inc(NextPW[n]);
        if NextPW[n] < PWCharSet.n then break
        else NextPW[n] := 0;
        dec(n);
    end;
    IncPW := TRUE;
end;

procedure BuildPW(Escape : Boolean);
var n : Integer;
    m : Integer;
    c : Char;
begin
    PW[0] := Chr(PWLen);
    m := 1;
    for n := 1 to PWLen do begin
        c := PWCharSet.c[NextPW[n]];
        if Escape and ((c = '"') or (c = '\')) then begin
            PW[m] := '\';
            inc(m);
            inc(PW[0]);
        end;
        PW[m] := c;
        inc(m);
    end;
end;

function CheckAllPWs : Boolean;
var NextSave : LongInt;
    Ok         : Boolean;
begin

    NextSave := 1;

    while TRUE do begin

        if NextSave <> 0 then begin
            if NextSave <> 1 then dec(NextSave)
            else begin
                SavePW;
                NextSave := PWSaveInt;
            end;
        end;

        BuildPW(FALSE);
        Ok := ZipPWCheck(PW, ZipBuf, ZDHdr.Crc32);

        if Ok then begin
            BuildPW(TRUE);
            rc := ExecPkunzip('-# -t -s"' + PW + '" ' + ZipfilePath + ' ' + MemberName);
            if rc = 0 then begin
                CheckAllPWs := TRUE;
                Exit;
            end;
        end;

        Ok := IncPW;
        if not Ok then begin
            CheckAllPWs := FALSE;
            Exit;
        end;
    end;
end;

begin

    WriteLn('ZipCrack v1.0 Copyright 1993 by Michael A. Quinlan');

    GetInput;

    if UseRamDisk then begin
        {$I-} MkDir(RamPath); {$I+}
        if IOResult <> 0 then
            ;
        if not CopyFile(PkunzipPath, RamPath + '\PKUNZIP.EXE') then begin
            WriteLn('Unable to copy ', PkunzipPath, ' to ', RamPath + '\PKUNZIP.EXE');
            Exit;
        end
        else PkunzipPath := RamPath + '\PKUNZIP.EXE';
        if not CopyFile(ZipfilePath, RamPath + '\' + ZipFilename) then begin
            WriteLn('Unable to copy ', ZipfilePath, ' to ', RamPath + '\' + ZipFilename);
            Exit;
        end
        else ZipfilePath := RamPath + '\' + ZipFilename;
    end;

{ Validate that PKUNZIP, the Zipfile, and the member of the Zipfile are }
{ still accessible.                                                        }

    rc := ExecPkunzip('-# -v ' + ZipfilePath + ' ' + MemberName);
    if rc <> 0 then begin
        WriteLn('Unable to locate ', MemberName, ' in ', ZipfilePath);
        Halt(3);
    end;

    Ok := ZipOpen(ZipFile, ZipfilePath, ZDEnd);
    if not Ok then Halt(3);

    Ok := ZipFindFile(ZipFile, MemberName, ZDEnd, ZDHdr, ZIpHdr);
    if not Ok then Halt(3);

    BlockRead(ZipFile, ZipBuf, sizeof(ZipBuf));

    if PWLen = 0 then PWLen := MinPWLen;
    Writeln('Testing passwords...');
    for PWLen := PWLen to MaxPWLen do begin
        if CheckAllPWs then begin
            Writeln('Password = "', PW, '"');
            IncPW;
            SavePW;
            Halt(0);
        end;
    end;

    WriteLn('Password not found!!!');
    Halt(1);
end.