Java DES encryption and decryption File

In Android development or Java Development, some files are often encrypted or decrypted. Below is a method I recently tested to encrypt and decrypt the files using DES. Record it to prevent forgetting it later!

The following code is directly pasted and detailed comments are written as follows:

Package COM. spring. des; import Java. io. bufferedreader; import Java. io. fileinputstream; import Java. io. filenotfoundexception; import Java. io. fileoutputstream; import Java. io. ioexception; import Java. io. inputstream; import Java. io. inputstreamreader; import Java. io. outputstream; import Java. security. invalidkeyexception; import Java. security. key; import Java. security. nosuchalgorithmexception; import javax. crypto. c Ipher; import javax. crypto. cipherinputstream; import javax. crypto. nosuchpaddingexception; import javax. crypto. spec. secretkeyspec;/**** des file encryption and decryption ** @ author spring sky <br> * Email: vipa1888@163.com <br> * QQ: 840950105 **/public class desfileencrypt {/*** list of file paths to be encrypted */public static string [] filepath = {"D:/sasdfp. SQL "};/*** list of encrypted file paths */public static string [] outfilepath = new string [filepath. leng Th]; Private Static final string key = "spring sky"; Public desfileencrypt () {super (); getkey (key); initcipher (); // initialize the encrypted file crateencryptfile ();} Private Key key;/***** decrypt the password */private cipher cipherdecrypt;/***** encrypt the password */private cipher cipherencrypt; /*** the encrypted file is flat and recorded in the encrypted file path **/private void crateencryptfile () {string outpath = NULL; For (INT I = 0; I <filepath. length; I ++) {try {outpath = filepath [I]. substri Ng (0, filepath [I]. lastindexof (". ") + ". bin "; encrypt (filepath [I], outpath); outfilepath [I] = outpath; system. out. println (filepath [I] + "encrypted, the encrypted file is:" + outfilepath [I]);} catch (exception e) {e. printstacktrace () ;}} system. out. println ("=========================================================== ============== ");} /*** the core of the encrypted file ** @ Param file * the file to be encrypted * @ Param destfile * the encrypted file name */Public void encrypt (string file, string destfile) Throws exception {inputstream is = new fileinputstream (File); outputstream out = new fileoutputstream (destfile); cipherinputstream CIS = new cipherinputstream (is, cipherencrypt ); byte [] buffer = new byte [1024]; int R; while (r = CIs. read (buffer)> 0) {out. write (buffer, 0, R);} CIs. close (); is. close (); out. close ();}/***** decrypt the file * @ Param destfile */Public void decrypt (string destfile) {try {inputstream I S = new fileinputstream (destfile); cipherinputstream CIS = new cipherinputstream (is, cipherdecrypt); bufferedreader reader = new bufferedreader (New inputstreamreader (CIS); string line = NULL; while (line = reader. readline ())! = NULL) {system. out. println (line);} reader. close (); CIS. close (); is. close ();} catch (filenotfoundexception e) {e. printstacktrace ();} catch (ioexception e) {e. printstacktrace () ;}} private void initcipher () {try {// encrypted cipherencrypt = cipher. getinstance ("des"); cipherencrypt. init (cipher. encrypt_mode, this. key); // the decrypted ciphercipherdecrypt = cipher. getinstance ("des"); cipherdecrypt. init (cipher. decrypt_mode, this. key);} catch (invalidkeyexception e) {e. printstacktrace ();} catch (nosuchalgorithmexception e) {e. printstacktrace ();} catch (nosuchpaddingexception e) {e. printstacktrace () ;}}/*** customize a key ** @ Param string */Public Key getkey (string keyrule) {// key = NULL; byte [] keybyte = keyrule. getbytes (); // create an empty octal group. The default value is 0 byte [] bytetemp = new byte [8]. // convert the specified rule into an eight-digit group for (INT I = 0; I <bytetemp. length & I <keybyte. length; I ++) {bytetemp [I] = keybyte [I];} key = new secretkeyspec (bytetemp, "des"); Return key ;} /*** decrypt the password ** @ return */public cipher getcipheredcrypt () {return cipherdecrypt;}/*** encrypt the password ** @ return */public cipher getcipherencrypt () {return cipherencrypt;}/***** test encryption and decryption * @ Param ARGs */public static void main (string [] ARGs) {desfileencrypt = new desfileencrypt (); desfileencrypt. decrypt (outfilepath [0]); // decrypt the first file and test the decrypted result }}