Android RSA公钥加密和私钥解密方法

一、公钥加密过程

/**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.decodeBase64(publicKey.getBytes());
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
//        String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
        return new String(Base64.encodeBase64(cipher.doFinal(str.getBytes("UTF-8"))));
//        return outStr;
    }

二、私钥解密过程

 /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @param privateKey 私钥
     * @return 铭文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str, String privateKey) throws Exception {
        //64位解码加密后的字符串
        byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
        //base64编码的私钥
        byte[] decoded = Base64.decodeBase64(privateKey.getBytes());
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        //RSA解密
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        String outStr = new String(cipher.doFinal(inputByte));
        return outStr;
    }