关于JAVA加密的例子

虽然DES是比较落后的算法，但是JAVA里的加密解密都差不多。
例子来自http://javaalmanac.com/egs/javax.crypto/DesString.html
public class DesEncrypter {
Cipher ecipher;
Cipher dcipher;

DesEncrypter(SecretKey key) {
try {
ecipher = Cipher.getInstance("DES");
dcipher = Cipher.getInstance("DES");
ecipher.init(Cipher.ENCRYPT_MODE, key);
dcipher.init(Cipher.DECRYPT_MODE, key);

} catch (javax.crypto.NoSuchPaddingException e) {
} catch (java.security.NoSuchAlgorithmException e) {
} catch (java.security.InvalidKeyException e) {
}
}

public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");

// Encrypt
byte[] enc = ecipher.doFinal(utf8);

// Encode bytes to base64 to get a string
return new sun.misc.BASE64Encoder().encode(enc);
} catch (javax.crypto.BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
} catch (java.io.IOException e) {
}
return null;
}

public String decrypt(String str) {
try {
// Decode base64 to get bytes
byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

// Decrypt
byte[] utf8 = dcipher.doFinal(dec);

// Decode using utf-8
return new String(utf8, "UTF8");
} catch (javax.crypto.BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
} catch (java.io.IOException e) {
}
return null;
}
}
Here's an example that uses the class:

try {
// Generate a temporary key. In practice, you would save this key.
SecretKey key = KeyGenerator.getInstance("DES").generateKey();

// Create encrypter/decrypter class
DesEncrypter encrypter = new DesEncrypter(key);

// Encrypt
String encrypted = encrypter.encrypt("Don't tell anybody!");

// Decrypt
String decrypted = encrypter.decrypt(encrypted);
} catch (Exception e) {
}