delphi如何给access加密解密 ( 积分: 0 )

我做一个小小的access数据库软件,我要给它加密,加密后用access是打不开的,但我要用delphi去连接的,也就是当连接时,是解密的,但此时用access也是打不开的?

不太明白楼主的意思？
数据加密还是数据库加密码保护？

同意楼上，加密码保护直接在Access中加，如果用ADO连接，在建立连接时输入密码就是了。就是客户自己改密码麻烦点儿，不过也可以实现。

解密的代码：
unit GetPass;
interface
uses
Windows, SysUtils, Classes, StdCtrls;
type
PassType = record
PassCode: string;
FileType: string;
end;

var
DateStr: DWord;
PassCode: WideString;
EncodeArray: array[0..19] of Word;
ReaderArray: array[0..19] of Word;
function ExecFile(FName: string): PassType;
procedure GetAccPass(Path: string;
DataType, DataPass: TEdit);
var
InhereCode: array[0..9] of Word =
($37EC, $FA9C, $E628, $608A, $367B, $B1DF, $4313, $33B1, $5B79, $2A7C);
UserCode8: array[0..9] of Word =
($8B86, $345D, $2EC6, $C613, $E454, $02F5, $8477, $DFCF, $1134, $C592);
UserCode: array[0..9] of Word =
($7B86, $C45D, $DEC6, $3613, $1454, $F2F5, $7477, $2FCF, $E134, $3592);
InCode97: array[0..19] of byte =
($86, $FB, $EC, $37, $5D, $44, $9C, $FA, $C6, $5E,
$28, $E6, $13, $00, $00, $00, $00, $00, $00, $00);
implementation
function ExecFile(FName: string): PassType;
function CovTime(FD: _FileTime): TDateTime;
var
TCT: _SystemTime;
Tmp: _FileTime;
begin
FileTimeToLocalFileTime(FD, Tmp);
FileTimeToSystemTime(Tmp, TCT);
Result := SystemTimeToDateTime(TCT);
end;

var
Stream: TFileStream;
i, n: integer;
TP: TSearchRec;
WTime: TDateTime;
WSec: DWord;
M, S: string;
Buf: array[0..200] of byte;
Date0: TDateTime;
Date1: TDateTime;
Date2: TDateTime;
const
XorStr = $823E6C94;
begin
FindFirst(FName, faAnyFile, TP);
Stream := TFileStream.Create(FName, fmOpenReadWrite);
Stream.Seek($00, 00);
Stream.Read(Buf[0], 200);
if Buf[$14] = 0 then
begin
PassCode := '';
Stream.Seek($42, 00);
Stream.Read(Buf[0], 20);
for i := 0 to 19 do
PassCode := PassCode + chr(Buf xor InCode97);
Result.PassCode := PassCode;
Result.FileType := 'ACCESS-97';
Exit;
end;

Date0 := EncodeDate(1978, 7, 01);
Date1 := EncodeDate(1989, 9, 17);
Date2 := EncodeDate(2079, 6, 05);
Stream.Seek($42, 00);
Stream.Read(ReaderArray[0], 40);
Stream.Seek($75, 00);
Stream.Read(DateStr, 4);
Stream.Free;
for i := $42 to $42 + 55 do
begin
if i = $72 then
M := '-' else
M := '';
S := S + #32 + M + IntToHex(Buf, 2);
end;
Delete(S, 1, 1);
if (DateStr >= $90000000) and (DateStr < $B0000000) then
begin
WSec := DateStr xor $903E6C94;
WTime := Date2 + WSec / 8192 * 2;
end else
begin
WSec := DateStr xor $803E6C94;
WTime := Date1 + WSec / 8192;
if WSec and $30000000 <> 0 then
begin
WSec := $40000000 - WSec;
WTime := Date1 - WSec / 8192 / 2;
end;
end;
if WTime < Date1 then
begin
for i := 0 to 9 do
begin
EncodeArray[i * 2] := (Trunc(WTime) - Trunc(Date0)) xor UserCode xor $F000;

EncodeArray[i * 2 + 1] := InhereCode;
end;
end;
if (WTime >= Date1) and (WTime < Date2) then
begin
for i := 0 to 9 do
begin
EncodeArray[i * 2] := (Trunc(WTime) - Trunc(Date1)) xor UserCode;
EncodeArray[i * 2 + 1] := InhereCode;
end;
end;
if WTime >= Date2 then
begin
for i := 0 to 9 do
begin
EncodeArray[i * 2] := (Trunc(WTime) - Trunc(Date1)) xor UserCode;
EncodeArray[i * 2 + 1] := InhereCode xor 1;

end;
end;
PassCode := '';
for i := 0 to 19 do
begin
N := EncodeArray xor ReaderArray;
if N <> 0 then
PassCode := PassCode + WideChar(N);
end;
Result.FileType := 'ACCESS-2000';
Result.PassCode := PassCode;
end;

procedure GetAccPass(Path: string;
DataType, DataPass: TEdit);
var
P: PassType;
begin
P := ExecFile(Path);
DataType.Text := P.FileType;
DataPass.Text := P.PassCode;
end;