Upload and download file encryption

When files are uploaded and downloaded, the files are encrypted.

1. Define Key

// encrypt the required key object Private Static Key key;

2, initialize the key (encryption and decryption method Getkey ("XX") in the same xx)

/*** Generate key based on parameters*/ Public Static voidGetKey (String strkey) {Try{keygenerator Generator= Keygenerator.getinstance ("DES"); Generator.init (NewSecureRandom (Strkey.getbytes ())); Key=Generator.generatekey (); } Catch(Exception e) {Throw NewRuntimeException ("Error Initializing Sqlmap class. Cause: "+e); }}

3. Encryption

/*** Encryption of files *@paramSrcfile *@throwsException*/ Public Static voidEncfile (File srcfile)throwsException {if(!srcfile.exists ()) {        Throw NewWarnexception ("file does not exist!) "); } String fileName=Srcfile.getabsolutepath (); inti = Filename.lastindexof (".")); if(i>0) {FileName= filename.substring (0, i); } File encfile=NewFile (fileName); GetKey ( "AAAA"); Cipher Cipher= Cipher.getinstance ("DES");    Cipher.init (Cipher.encrypt_mode,key); InputStream is=NewFileInputStream (srcfile); CipherOutputStream out=NewCipherOutputStream (NewFileOutputStream (encfile), cipher);    Ioutils.copylarge (is, out);    Is.close ();    Out.flush ();　　　    Out.close (); Srcfile.delete ();}

4. Decryption

/*** Decryption *@paramSrcfile *@paramsuffix *@return * @throwsException*/ Public StaticFileInputStream decfile (File srcfile,string suffix)throwsException {fileinputstream fis=NULL; if(!srcfile.exists ()) {        Throw NewWarnexception ("file does not exist!) "); } String fileName= Srcfile.getabsolutepath () + "." +suffix; File Decfile=NewFile (fileName); GetKey ( "AAAA"); Cipher Cipher= Cipher.getinstance ("DES");    Cipher.init (Cipher.decrypt_mode, key); InputStream is=NewFileInputStream (srcfile); OutputStream out=NewFileOutputStream (Decfile); CipherOutputStream Cos=NewCipherOutputStream (out, cipher); byte[] buffer =New byte[1024]; intlength;  while(length = is.read (buffer)) >= 0) {cos.write (buffer,0, length); } FIS=NewFileInputStream (Decfile);    Cos.close ();    Out.close ();    Is.close (); returnfis;}

Upload and download file encryption