CipherUtils.java

package com.foundkey.example;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class CipherUtils {
    public  static byte[] rsaPublicKey;
    public static byte[] rsaPrivateKey;

    static {
        updateRASKey();
    }

    // 获取信息的MD5值
    public static byte[] getMD2(byte[] content) {
        byte[] hash = null;
        try {
            hash = MessageDigest.getInstance("MD2").digest(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return hash;
    }

    // 获取信息的MD5值
    public static byte[] getMD5(byte[] content) {
        byte[] hash = null;
        try {
            hash = MessageDigest.getInstance("MD5").digest(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return hash;
    }

    // 获取信息的SHA-1
    public static byte[] getSHA1(byte[] content) {
        byte[] hash = null;
        try {
            hash = MessageDigest.getInstance("SHA-1").digest(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return hash;
    }

    // 获取信息的SHA-256
    public  static byte[] getSHA256(byte[] content) {
        byte[] hash = null;
        try {
            hash = MessageDigest.getInstance("SHA-256").digest(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return hash;
    }

    // 更新RAS的密钥对
    public static void updateRASKey() {
        try {
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(1024);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            rsaPublicKey = keyPair.getPublic().getEncoded();
            rsaPrivateKey = keyPair.getPrivate().getEncoded();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }

    // RAS加密
    public static byte[] rsaEncrypt(byte[] content) {
        byte[] result = null;
        try {
            Cipher cipher = Cipher.getInstance("RSA");
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(rsaPublicKey);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(keySpec);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            result = cipher.doFinal(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        }

        return result;
    }

    // RSA解密
    public static byte[] rsaDecrypt(byte[] content) {
        byte[] result = null;

        try {
            Cipher cipher = Cipher.getInstance("RSA");
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(rsaPrivateKey);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            result = cipher.doFinal(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        }

        return  result;
    }

    // AES使用CBC模式需要提供初始化向量，由密码的MD5前16位生成
    private static byte[] getIV(byte[] password) {
        byte[] key = new byte[16];
        byte[] passwordMD5 = getMD5(password);

        System.arraycopy(passwordMD5, 0, key, 0, 16);
        return  key;
    }

    // 根据密码生成AES密钥
    private static SecretKey generateAESKey(byte[] password) {
        SecretKey secretKey = null;
        KeyGenerator keyGenerator = null;
        try {
            keyGenerator = KeyGenerator.getInstance("AES");
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG"); // SHA1 Pseudo random number generator
            random.setSeed(password);
            keyGenerator.init(128, random);
            secretKey = keyGenerator.generateKey();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return secretKey;
    }

    // AES加密
    public static byte[] aesEncrypt(byte[] content, byte[] password) {
        byte[] result = null;


        SecretKey key = new SecretKeySpec(generateAESKey(password).getEncoded(), "AES");
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            IvParameterSpec iv = new IvParameterSpec(getIV(password));  // 测试方便，这里初始化向量使用密码
            cipher.init(Cipher.ENCRYPT_MODE, key, iv);
            result = cipher.doFinal(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        }

        return result;
    }

    // AES解密
    public static byte[] aesDecrypt(byte[] content, byte[] password) {
        byte[] result = null;

        SecretKey key = new SecretKeySpec(generateAESKey(password).getEncoded(), "AES");
        try{
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            IvParameterSpec iv = new IvParameterSpec(getIV(password)); // 测试方便，这里初始化向量使用密码
            cipher.init(Cipher.DECRYPT_MODE, key, iv);
            result = cipher.doFinal(content);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        }

        return result;
    }

    public static String toHexString(byte[] hash) {
        if (hash == null) {
            return "";
        }

        StringBuilder sb = new StringBuilder(hash.length * 2);
        for (byte b : hash) {
            if ((b & 0xff) < 0x10) {
                sb.append("0");
            }
            sb.append(Integer.toHexString(b & 0xff));
        }
        return sb.toString();
    }

    public static String toBase64(byte[] content) {
        if (content == null) {
            return "";
        }

        return Base64.getEncoder().encodeToString(content);
    }
}