{$WRITEABLECONST ON}

unit LbRandom;

Windows, { only needed for get tick count }

Types,

Libc,

Sysutils,

Math,

LbCipher;

tmp = 1;

TLbRandomGenerator = class

private

RandCount : Integer;

Seed : TMD5Digest;

procedure ChurnSeed;

public

constructor Create;

destructor Destroy; override;

procedure RandomBytes( var buff; len : DWORD );

end;

TLbRanLFS = class

private

ShiftRegister : DWORD;

procedure SetSeed;

function LFS : byte;

public

constructor Create;

destructor Destroy; override;

procedure FillBuf( var buff; len : DWORD );

end;

constructor TLbRandomGenerator.create;

inherited;

ChurnSeed;

end;

destructor TLbRandomGenerator.Destroy;

RandCount := 0;

FillChar( Seed, SizeOf( Seed ), $00 );

inherited;

end;

procedure TLbRandomGenerator.ChurnSeed;

RandomSeed : array[ 0..15 ] of byte;

Context : TMD5Context;

lcg : TLbRanLFS;

i : integer;

lcg := TLbRanLFS.Create;

try

lcg.FillBuf( RandomSeed, SizeOf( RandomSeed ));

for i := 0 to 4 do begin

InitMD5( Context );

UpdateMD5( Context, Seed, SizeOf( Seed ));

UpdateMD5( Context, RandomSeed, SizeOf( RandomSeed ));

FinalizeMD5( Context, Seed );

end;

finally

lcg.Free;

end;

end;

procedure TLbRandomGenerator.RandomBytes( var buff; len : DWORD );

Context : TMD5Context;

TmpDig : TMD5Digest;

Index : DWORD;

m : integer;

SizeOfTmpDig : integer;

SizeOfTmpDig := SizeOf( TmpDig );

Index := 0;

if(( len - Index ) < 16 )then

m := len - Index

else

m := SizeOfTmpDig;

While Index < len do begin

InitMD5( Context );

UpdateMD5( Context, Seed, sizeof( Seed ));

UpdateMD5( Context, RandCount, sizeof( RandCount ));

FinalizeMD5( Context, TmpDig );

inc( RandCount );

move( tmpDig, TByteArray( buff )[ Index ], m );

inc( Index, m );

if(( len - Index ) < 16 )then

m := len - Index

else

m := SizeOfTmpDig;

end;

end;

constructor TLbRanLFS.Create;

inherited;

SetSeed;

end;

destructor TLbRanLFS.Destroy;

inherited;

end;

procedure TLbRanLFS.FillBuf( var buff; len : DWORD );

l : DWORD;

b : byte;

tmp_byt : byte;

for l := 0 to pred( len )do begin

tmp_byt := 0;

for b := 0 to 7 do begin

tmp_byt := ( tmp_byt shl 1 ) or LFS;

end;

TByteArray( buff )[ l ] := tmp_byt;

end;

end;

procedure TLbRanLFS.SetSeed;

hold : integer = 1;

_time : TSYSTEMTIME;

fd : pIOFile;

while true do begin

ShiftRegister := hold;

GetLocalTime( _time );

ShiftRegister := ( ShiftRegister shl ( hold and $0000000F )) xor

(( DWORD( _time.wHour or _time.wSecond ) shl 16 ) or

( DWORD( _time.wMinute or _time.wMilliseconds )));

hold := ShiftRegister;

inc( hold );

fd := fopen( '/dev/random', 'r' );

fread( @ShiftRegister, SizeOf( byte ), SizeOf( ShiftRegister ), fd );

fclose( fd );

if( ShiftRegister <> 0 )then

break;

end;

end;

function TLbRanLFS.LFS : byte;

ShiftRegister := (((( ShiftRegister shr 31 ) xor

( ShiftRegister shr 6 ) xor

( ShiftRegister shr 4 ) xor

( ShiftRegister shr 2 ) xor

( ShiftRegister shr 1 ) xor

( ShiftRegister )) and $00000001 ) shl 31 ) or

( ShiftRegister shr 1 );

result := ShiftRegister and $00000001;

end;

end.