e464. encrypting with des using a pass phrase.txt

来自「这里面包含了一百多个JAVA源文件」· 文本 代码 · 共 88 行

This example demonstrates how to use a pass phrase (a string password of multiple words) for encryption. 
    public class DesEncrypter {
        Cipher ecipher;
        Cipher dcipher;
    
        // 8-byte Salt
        byte[] salt = {
            (byte)0xA9, (byte)0x9B, (byte)0xC8, (byte)0x32,
            (byte)0x56, (byte)0x35, (byte)0xE3, (byte)0x03
        };
    
        // Iteration count
        int iterationCount = 19;
    
        DesEncrypter(String passPhrase) {
            try {
                // Create the key
                KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
                SecretKey key = SecretKeyFactory.getInstance(
                    "PBEWithMD5AndDES").generateSecret(keySpec);
                ecipher = Cipher.getInstance(key.getAlgorithm());
                dcipher = Cipher.getInstance(key.getAlgorithm());
    
                // Prepare the parameter to the ciphers
                AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
    
                // Create the ciphers
                ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
                dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
            } catch (java.security.InvalidAlgorithmParameterException e) {
            } catch (java.security.spec.InvalidKeySpecException e) {
            } 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 is an example that uses the class
    try {
        // Create encrypter/decrypter class
        DesEncrypter encrypter = new DesEncrypter("My Pass Phrase!");
    
        // Encrypt
        String encrypted = encrypter.encrypt("Don't tell anybody!");
    
        // Decrypt
        String decrypted = encrypter.decrypt(encrypted);
    } catch (Exception e) {
    }