常用加解密工具类（MD5、SHA、DES、AES、RSA）

MD5 单向加密

/**
 * 返回MD5单向加密后的十六进制字符串
 * @param data
 * @return
 * @throws Exception
 */
public String getEncryptForHex(byte[] data) throws Exception {
    byte[] digestData = encrypt(data);
    StringBuffer hex = new StringBuffer();
    for(int i = 0; i < digestData.length; i++)
    {
        int h = ((int)digestData[i]) & 0XFF;
        if(h < 16)
        {
            hex.append("0");
        }
        hex.append(Integer.toHexString(h));
    }
     
    return hex.toString();
}

DES 对称加密

public byte[] encrypt(byte[] data) throws Exception {
    if(secretKey == null || "".equals(secretKey)) {
        throw new Exception("scretKey need to exists");
    }
    SecretKey md5Key = getKey(secretKey);
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.ENCRYPT_MODE, md5Key);
    return cipher.doFinal(data);
}

public byte[] decrypt(byte[] data) throws Exception {
    if(secretKey == null || "".equals(secretKey)) {
        throw new Exception("scretKey need to exists");
    }
    SecretKey md5Key = getKey(secretKey);
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.DECRYPT_MODE, md5Key);
    return cipher.doFinal(data);
}

RSA 非对称加密——私钥加密 & 私钥解密 & 私钥签名

public byte[] encrypt(byte[] data) throws Exception {
    PrivateKey rsaPrivateKey = getRSAPrivateKey();
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.ENCRYPT_MODE, rsaPrivateKey);
    return cipher.doFinal(data);
}

public byte[] decrypt(byte[] data) throws Exception {
    PrivateKey rsaPrivateKey = getRSAPrivateKey();
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.DECRYPT_MODE, rsaPrivateKey);
    return cipher.update(data);
}

/**
 * 使用私钥 对数据进行签名
 * @param data
 * @return
 * @throws Exception
 */
public String sign(byte[] data) throws Exception {
    PrivateKey rsaPrivateKey = getRSAPrivateKey();
    Signature signature = Signature.getInstance(SIGN_ALGORITHM);
    signature.initSign(rsaPrivateKey);
    signature.update(data);
    return encoder(signature.sign());
}

RSA 非对称加密——公钥加密 & 公钥解密 & 公钥校验签名

public byte[] encrypt(byte[] data) throws Exception {
    if(publicKey == null || "".equals(publicKey)) {
        throw new Exception("publicKey is need exists");
    }
    PublicKey rsaPublicKey = getRSAPublicKey(publicKey);
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.ENCRYPT_MODE, rsaPublicKey);
    return cipher.doFinal(data);
}

public byte[] decrypt(byte[] data) throws Exception {
    if(publicKey == null || "".equals(publicKey)) {
        throw new Exception("publicKey is need exists");
    } 
    PublicKey rsaPublicKey = getRSAPublicKey(publicKey);
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.DECRYPT_MODE, rsaPublicKey);
    return cipher.doFinal(data);
}

/**
 * 使用公钥校验签名
 * @param data
 * @param sign
 * @return
 * @throws Exception
 */
public boolean verifySign(byte[] data, String sign) throws Exception {
    if(publicKey == null || "".equals(publicKey)) {
        throw new Exception("publicKey is need exists");
    }
    PublicKey rsaPublicKey = getRSAPublicKey(publicKey);
    Signature signature = Signature.getInstance(SIGN_ALGORITHM);
    signature.initVerify(rsaPublicKey);
    signature.update(data);
    return signature.verify(decoder(sign));
}