对称算法小结

桃扇骨 2022-06-01 13:19 192阅读 0赞

最近项目紧，博客少有更新了。好不容易空闲下来再继续总结些东西。

之前对RSA算法进行了总结。今天将对称算法的部分补上，包括DES，3DES，AES三种。

基本上可说的部分不多，代码也好懂，便直接上CODE了。

import java.security.InvalidAlgorithmParameterException;
    import java.security.InvalidKeyException;
    import java.security.NoSuchAlgorithmException;
    import java.util.Arrays;
    
    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.NoSuchPaddingException;
    import javax.crypto.spec.IvParameterSpec;
    import javax.crypto.spec.SecretKeySpec;
    
    /**
     * Created by user on 2018/1/30.
     */
    
    public class CryptoUtil {
        public enum ALGO{
            DES,TripleDES,AES
        }
    
        public enum PADDING {
            PKCS5,NO
        }
    
        public enum MODE{
            CBC,ECB
        }
    
        public static byte[] process(ALGO algo,
                                     MODE mode,
                                     PADDING padding,
                                     byte[] key,
                                     byte[] data,
                                     boolean doEncrypt){
            try {
                SecretKeySpec keySpec=new SecretKeySpec(key, toAlgoStr(algo));
                Cipher cipher= Cipher.getInstance(toAlgoStr(algo)+"/"+toModeStr(mode)+"/"+toPaddingStr(padding));
                if(mode==MODE.CBC){
                    cipher.init(doEncrypt?Cipher.ENCRYPT_MODE:Cipher.DECRYPT_MODE, keySpec,getIv(algo));
                }else {
                    cipher.init(doEncrypt?Cipher.ENCRYPT_MODE:Cipher.DECRYPT_MODE, keySpec);
                }
    
                return cipher.doFinal(data);
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            } catch (NoSuchPaddingException e) {
                e.printStackTrace();
            } catch (InvalidKeyException e) {
                e.printStackTrace();
            } catch (BadPaddingException e) {
                e.printStackTrace();
            } catch (IllegalBlockSizeException e) {
                e.printStackTrace();
            } catch (InvalidAlgorithmParameterException e) {
                e.printStackTrace();
            }
            return null;
        }
    
        public static String toAlgoStr(ALGO algo){
            switch (algo){
                case AES:
                    return "AES";
                case DES:
                    return "DES";
                case TripleDES:
                    return "DESede";
            }
            return null;
        }
    
        public static String toPaddingStr(PADDING PADDING){
            switch (PADDING){
                case NO:
                    return "NoPadding";
                case PKCS5:
                    return "PKCS5Padding";
            }
            return null;
        }
    
        public static String toModeStr(MODE mode){
            switch (mode){
                case CBC:
                    return "CBC";
                case ECB:
                    return "ECB";
            }
            return null;
        }
    
        private static IvParameterSpec getIv(ALGO algo){
            int keyLen=0;
            switch (algo){
                case AES:
                    keyLen=16;
                    break;
                case DES:
                case TripleDES:
                    keyLen=8;
                    break;
            }
    
            byte[] IV_PARAMETER=new byte[keyLen];
            Arrays.fill(IV_PARAMETER,(byte)0x00);
            return new IvParameterSpec(IV_PARAMETER);
        }
    }