JW

實作靜態類別 StringEncrypt 來提供字串加解密功能。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
using System.IO;

namespace StringEncrypt
{
    public static class StringEncrypt
    {
        /// <summary>
        /// 字串加密(非對稱式)
        /// </summary>
        /// <param name="Source">加密前字串</param>
        /// <param name="CryptoKey">加密金鑰</param>
        /// <returns>加密後字串</returns>
        public static string aesEncryptBase64(string SourceStr, string CryptoKey)
        {
            string encrypt = "";
            try
            {
                AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
                MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
                SHA256CryptoServiceProvider sha256 = new SHA256CryptoServiceProvider();
                byte[] key = sha256.ComputeHash(Encoding.UTF8.GetBytes(CryptoKey));
                byte[] iv = md5.ComputeHash(Encoding.UTF8.GetBytes(CryptoKey));
                aes.Key = key;
                aes.IV = iv;

                byte[] dataByteArray = Encoding.UTF8.GetBytes(SourceStr);
                using (MemoryStream ms = new MemoryStream())
                using (CryptoStream cs = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(dataByteArray, 0, dataByteArray.Length);
                    cs.FlushFinalBlock();
                    encrypt = Convert.ToBase64String(ms.ToArray());
                }
            }
            catch (Exception e)
            {
                System.Windows.Forms.MessageBox.Show(e.Message);
            }
            return encrypt;
        }

        /// <summary>
        /// 字串解密(非對稱式)
        /// </summary>
        /// <param name="Source">解密前字串</param>
        /// <param name="CryptoKey">解密金鑰</param>
        /// <returns>解密後字串</returns>
        public static string aesDecryptBase64(string SourceStr, string CryptoKey)
        {
            string decrypt = "";
            try
            {
                AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
                MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
                SHA256CryptoServiceProvider sha256 = new SHA256CryptoServiceProvider();
                byte[] key = sha256.ComputeHash(Encoding.UTF8.GetBytes(CryptoKey));
                byte[] iv = md5.ComputeHash(Encoding.UTF8.GetBytes(CryptoKey));
                aes.Key = key;
                aes.IV = iv;

                byte[] dataByteArray = Convert.FromBase64String(SourceStr);
                using (MemoryStream ms = new MemoryStream())
                {
                    using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(dataByteArray, 0, dataByteArray.Length);
                        cs.FlushFinalBlock();
                        decrypt = Encoding.UTF8.GetString(ms.ToArray());
                    }
                }
            }
            catch (Exception e)
            { 
                System.Windows.Forms.MessageBox.Show(e.Message);
            }
            return decrypt;
        }

    }
}

應用範例：

【加密按鈕】的 Click 事件程式碼如下：

private void btn_Encrypt_Click(object sender, EventArgs e)
{
	try
	{
		tb_Encrypt_After.Text = StringEncrypt.aesEncryptBase64(tb_Encrypt_Before.Text, tb_Encrypt_Key.Text);
		tb_Decrypt_Before.Text = tb_Encrypt_After.Text;
		tb_Decrypt_Key.Text = tb_Encrypt_Key.Text;
		tb_Decrypt_After.Text = "";
	}
	catch (Exception ex)
	{
		MessageBox.Show(ex.Message);
	}
}

按下【加密按鈕】後，產生加密後的字串，畫面如下：

【解密按鈕】的 Click 事件程式碼如下：

private void btn_Decrypt_Click(object sender, EventArgs e)
{
	try
	{
		tb_Decrypt_After.Text = StringEncrypt.aesDecryptBase64(tb_Decrypt_Before.Text, tb_Decrypt_Key.Text);
	}
	catch (Exception ex)
	{
		MessageBox.Show(ex.Message);
	}
}

按下【解密按鈕】後，產生加密後的字串，畫面如下：

輕鬆簡單快速完成字串加解密功能。

 

參考資料：

1. 王者歸來 C# 完全開發範例集(第三版) - 實例 046 對字串進行加密與解密 ..... P.3-19
2. 余小章 @ 大內殿堂 - [C#.NET] 字串及檔案 利用 DES / AES 演算法加解密