Simplest DES encryption algorithm implementation, des encryption algorithm

Simplest DES encryption algorithm implementation, des encryption algorithm

Base64.java

Package com. mstf. des; import java. io. unsupportedEncodingException;/*** base64 encoding/decoding * @ author ceet **/public class Base64 {public static String encode (String data) {return new String (encode (data. getBytes ();} public static String decode (String data) {try {return new String (decode (data. toCharArray (), "UTF-8");} catch (UnsupportedEncodingException e) {e. printStackTrace (); return null ;}} private st Atic char [] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 +/= ". toCharArray (); private static byte [] codes = new byte [256]; static {for (int I = 0; I <256; I ++) {codes [I] =-1 ;}for (int I = 'a'; I <= 'Z'; I ++) {codes [I] = (byte) (I-'A') ;}for (int I = 'a'; I <= 'Z'; I ++) {codes [I] = (byte) (26 + I-'A') ;}for (int I = '0'; I <= '9'; I ++) {codes [I] = (byte) (52 + I -' 0 ');} codes [' + '] = 62; codes ['/'] = 63;} public static char [] encode (byte [] data) {char [] out = new char [(data. length + 2)/3) * 4]; for (int I = 0, index = 0; I <data. length; I + = 3, index + = 4) {boolean quad = false; boolean trip = false; int val = (0xFF & (int) data [I]); val <= 8; if (I + 1) <data. length) {val | = (0xFF & (int) data [I + 1]); trip = true;} val <= 8; if (I + 2) <data. length) {val | = (0xFF & (int) data [I + 2]); quad = true;} out [index + 3] = alphabet [(quad? (Val & 0x3F): 64)]; val >>=6; out [index + 2] = alphabet [(trip? (Val & 0x3F): 64)]; val >>=6; out [index + 1] = alphabet [val & 0x3F]; val >>= 6; out [index + 0] = alphabet [val & 0x3F];} return out;} public static byte [] decode (char [] data) {int tempLen = data. length; for (int ix = 0; ix <data. length; ix ++) {if (data [ix]> 255) | codes [data [ix] <0) {-- tempLen ;}} int len = (tempLen/4) * 3; if (tempLen % 4) = 3) {len + = 2;} if (tempLen % 4) = 2) {len + = 1;} byt E [] out = new byte [len]; int shift = 0; int accum = 0; int index = 0; for (int ix = 0; ix <data. length; ix ++) {int value = (data [ix]> 255 )? -1: codes [data [ix]; if (value> = 0) {accum <= 6; shift + = 6; accum | = value; if (shift> = 8) {shift-= 8; out [index ++] = (byte) (accum> shift) & 0xff );}}} if (index! = Out. length) {throw new Error ("Miscalculated data length (wrote" + index + "instead of" + out. length + ")");} return out ;}}

DESUtil. java

Package com. mstf. des; import java. security. key; import java. security. secureRandom; import javax. crypto. cipher; import javax. crypto. keyGenerator;/*** DES symmetric algorithm (encryption/Decryption) ** @ author ceet **/public class DESUtil {private Key key; public DESUtil (String strKey) {setKey (strKey);} public void setKey (String strKey) {try {KeyGenerator generator = KeyGenerator. getInstance ("DES"); generator. init (new SecureRandom (strKey. getBytes (); // generate keythis Based on the parameter. key = generator. generateKey ();} catch (Exception e) {e. printStackTrace () ;}} public String encrypt (String source) {return encrypt (source, "UTF-8");} public String decrypt (String encryptedData) {return decrypt (encryptedData, "UTF-8");} public String encrypt (String source, String charSet) {String encrypt = null; try {byte [] ret = encrypt (source. getBytes (charSet); encrypt = new String (Base64.encode (ret);} catch (Exception e) {e. printStackTrace (); encrypt = null;} return encrypt;} public String decrypt (String encryptedData, String charSet) {String descryptedData = null; try {byte [] ret = descrypt (Base64.decode (encryptedData. toCharArray (); descryptedData = new String (ret, charSet);} catch (Exception e) {e. printStackTrace (); descryptedData = null;} return descryptedData;} private byte [] encrypt (byte [] primaryData) {try {Cipher cipher = Cipher. getInstance ("DES"); // The Cipher object actually completes the encryption operation cipher. init (Cipher. ENCRYPT_MODE, this. key); // use the key to initialize the Cipher object (encrypted) return cipher. doFinal (primaryData);} catch (Exception e) {e. printStackTrace (); return null ;}} private byte [] descrypt (byte [] encryptedData) {try {Cipher cipher = Cipher. getInstance ("DES"); // The Cipher object actually completes the decryption operation cipher. init (Cipher. DECRYPT_MODE, this. key); // use the key to initialize the Cipher object (decryption) return cipher. doFinal (encryptedData);} catch (Exception e) {e. printStackTrace (); return null ;}} public static void main (String [] args) {String code = "ceet"; DESUtil desUtil = new DESUtil ("key "); string encrypt = desUtil. encrypt (code); String decrypt = desUtil. decrypt (encrypt); System. out. println ("original content:" + code); System. out. println ("encryption:" + encrypt); System. out. println ("decryption:" + decrypt );}}