delphi - Encrypt/Decrypt a MS Access 2000 (*.mdb) Database File (Extra Security) -

for security, encrypt/decrypt ms access 2000 (*.mdb) database file.

i using delphi 7 , looking free or opensource solution (possible 2 functions allow pass file name , key).

i perform decrypt before app starts, , encrypt when app shuts down. best places this. oncreate, ondestroy events?

i assume first have create small utility uses encrypt portion of solution encrypt database file first?

thanks

i understand reasons have encrypt old access database , because security of access 2000 , 2003 weak. primary recommendation try upgrade access 2007 or higher uses microsoft cryptographic api, , incorporates significant improvements in security.

if can't upgrade, here leave option encrypt mdb file.

1) encrypt data can use jwawincrypt unit part of jedi jwscl library, can download library here.

check sample function uses 3des algorithm encrypt file.

uses   classes,   jwawintype,   jwawincrypt,   sysutils;   procedure cryptfile(const infilename, outfilename, password: ansistring; encrypt: boolean); const   buffersize=1024*64; var   streamsource  : tfilestream;   streamdest    : tfilestream;   cryptprov     : hcryptprov;   crypthash     : hcrypthash;   cryptkey      : hcryptkey;   buffer        : lpbyte;   bytesin       : dword;   final         : boolean; begin   cryptacquirecontext(cryptprov, nil, nil, prov_rsa_full, crypt_verifycontext);   try       cryptcreatehash(cryptprov, calg_3des_112, 0, 0, crypthash);       try         crypthashdata(crypthash, @password[1], length(password), 0);         cryptderivekey(cryptprov, calg_3des, crypthash, 0, cryptkey);               cryptdestroyhash(crypthash);       end;        streamsource := tfilestream.create(infilename, fmopenread or fmsharedenywrite);       streamdest   := tfilestream.create(outfilename, fmcreate);       try         getmem(buffer, buffersize);         try             repeat               bytesin   := streamsource.read(buffer^, buffersize);               final     := (streamsource.position >= streamsource.size);               if encrypt                 cryptencrypt(cryptkey, 0, final, 0, buffer, bytesin, bytesin)               else               cryptdecrypt(cryptkey, 0, final, 0, buffer, bytesin);               streamdest.write(buffer^, bytesin);             until final;                  freemem(buffer, buffersize);         end;                streamsource.free;         streamdest.free;       end;       cryptreleasecontext(cryptprov, 0);   end; end; 

and use in way

to encrypt file

 cryptfile('c:\temp\in.zip', 'c:\temp\out.zip','fdkjldf3832kka83' ,true); 

to decrypt file

 cryptfile('c:\temp\out.zip', 'c:\temp\in.zip','fdkjldf3832kka83' ,true); 

2) location of code encryot , decrypt data, depends of design of application.

3) keep in mind if application crashes data unprotected.

4) maybe best option build small application decrypt data , launch main application , stay monitoring status until main application ends. , encypt data again.