■ AesCryptoServiceProvider 클래스를 사용해 암호화/복호화하는 방법을 보여준다.
▶ SecurityHelper.cs
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using System; using System.IO; using System.Security.Cryptography; using System.Text; namespace TestProject { /// <summary> /// 보안 헬퍼 /// </summary> public static class SecurityHelper { //////////////////////////////////////////////////////////////////////////////////////////////////// Field ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Private #region Field /// <summary> /// RNG 암호 서비스 공급자 /// </summary> private static RNGCryptoServiceProvider _provider = new RNGCryptoServiceProvider(); #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Public #region 문자열로 암호화하기 - EncryptToString(source, password, salt) /// <summary> /// 문자열로 암호화하기 /// </summary> /// <param name="source">소스 문자열</param> /// <param name="password">패스워드</param> /// <param name="salt">솔트</param> /// <returns>암호화 문자열</returns> public static string EncryptToString(string source, string password, string salt) { return GetHexadecimalString(Encrypt(source, password, salt)); } #endregion #region 문자열에서 복호화하기 - DecryptFromString(source, password, salt) /// <summary> /// 문자열에서 복호화하기 /// </summary> /// <param name="source">소스 문자열</param> /// <param name="password">패스워드</param> /// <param name="salt">솔트</param> /// <returns>복호화 문자열</returns> public static string DecryptFromString(string source, string password, string salt) { return Decrypt(GetByteArrayFromHexadecimalString(source), password, salt); } #endregion #region 임의 정수 값 구하기 - GetRandomIntegerValue(minimumValue, maximumValue) /// <summary> /// 임의 정수 값 구하기 /// </summary> /// <param name="minimumValue">최소 값</param> /// <param name="maximumValue">최대 값</param> /// <returns>임의 정수 값</returns> public static int GetRandomIntegerValue(int minimumValue, int maximumValue) { uint scale = uint.MaxValue; while(scale == uint.MaxValue) { byte[] byteArray = new byte[4]; _provider.GetBytes(byteArray); scale = BitConverter.ToUInt32(byteArray, 0); } return (int)(minimumValue + (maximumValue - minimumValue) * (scale / (double)uint.MaxValue)); } #endregion #region 임의 솔트 구하기 - GetRandomSalt() /// <summary> /// 임의 솔트 구하기 /// </summary> /// <returns>임의 솔트</returns> public static string GetRandomSalt() { int byteArrayLength = GetRandomIntegerValue(10, 20); byte[] saltByteArray = new byte[byteArrayLength]; _provider.GetBytes(saltByteArray); return GetHexadecimalString(saltByteArray); } #endregion //////////////////////////////////////////////////////////////////////////////// Private #region 16진수 문자열에서 바이트 배열 구하기 - GetByteArrayFromHexadecimalString(source) /// <summary> /// 16진수 문자열에서 바이트 배열 구하기 /// </summary> /// <param name="source">소스 문자여</param> /// <returns>바이트 배열</returns> private static byte[] GetByteArrayFromHexadecimalString(string source) { source = source.Replace(" ", string.Empty); int byteCount = source.Length / 2; byte[] targetByteArray = new byte[byteCount]; for(int i = 0; i < byteCount; i++) { targetByteArray[i] = Convert.ToByte(source.Substring(2 * i, 2), 16); } return targetByteArray; } #endregion #region 16진수 문자열 구하기 - GetHexadecimalString(sourceByteArray) /// <summary> /// 16진수 문자열 구하기 /// </summary> /// <param name="sourceByteArray">소스 바이트 배열</param> /// <returns>16진수 문자열</returns> private static string GetHexadecimalString(byte[] sourceByteArray) { string target = string.Empty; foreach(byte sourceByte in sourceByteArray) { target += " " + sourceByte.ToString("X2"); } if(target.Length > 0) { target = target.Substring(1); } return target; } #endregion #region 키/초기 값 만들기 - MakeKeyAndInitialValue(password, saltByteArray, keySizeBitCount, blockSizeBitCount, keyByteArray, initialValueByteArray) /// <summary> /// 키/초기 값 만들기 /// </summary> /// <param name="password">패스워드</param> /// <param name="saltByteArray">솔트 바이트 배열</param> /// <param name="keySizeBitCount">키 크기 비트 카운트</param> /// <param name="blockSizeBitCount">블럭 크기 비트 카운트</param> /// <param name="keyByteArray">키 바이트 배열</param> /// <param name="initialValueByteArray">초기 값 바이트 배열</param> private static void MakeKeyAndInitialValue ( string password, byte[] saltByteArray, int keySizeBitCount, int blockSizeBitCount, ref byte[] keyByteArray, ref byte[] initialValueByteArray ) { Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(password, saltByteArray, 513); keyByteArray = rfc2898DeriveBytes.GetBytes(keySizeBitCount / 8); initialValueByteArray = rfc2898DeriveBytes.GetBytes(blockSizeBitCount / 8); } #endregion #region 암호화/복호화하기 - EncryptOrDecrypt(password, sourceByteArray, salt, encrypt) /// <summary> /// 암호화/복호화하기 /// </summary> /// <param name="password">패스워드</param> /// <param name="sourceByteArray">소스 바이트 배열</param> /// <param name="salt">솔트</param> /// <param name="encrypt">암호화 여부</param> /// <returns>암호화/복호화 바이트 배열</returns> private static byte[] EncryptOrDecrypt(string password, byte[] sourceByteArray, string salt, bool encrypt) { AesCryptoServiceProvider provider = new AesCryptoServiceProvider(); int keySizeBitCount = 0; for(int i = 1024; i >= 1; i--) { if(provider.ValidKeySize(i)) { keySizeBitCount = i; break; } } int blockSizeBitCount = provider.BlockSize; byte[] saltByteArray = GetByteArrayFromHexadecimalString(salt); byte[] keyByteArray = null; byte[] initialValueByteArray = null; MakeKeyAndInitialValue(password, saltByteArray, keySizeBitCount, blockSizeBitCount, ref keyByteArray, ref initialValueByteArray); ICryptoTransform cryptoTransform; if(encrypt) { cryptoTransform = provider.CreateEncryptor(keyByteArray, initialValueByteArray); } else { cryptoTransform = provider.CreateDecryptor(keyByteArray, initialValueByteArray); } MemoryStream targetStream = new MemoryStream(); CryptoStream cryptoStream = new CryptoStream(targetStream, cryptoTransform, CryptoStreamMode.Write); cryptoStream.Write(sourceByteArray, 0, sourceByteArray.Length); try { cryptoStream.FlushFinalBlock(); } catch(CryptographicException) { } catch { throw; } byte[] targetByteArray = targetStream.ToArray(); try { cryptoStream.Close(); } catch(CryptographicException) { } catch { throw; } targetStream.Close(); return targetByteArray; } #endregion #region 암호화하기 - Encrypt(source, password, salt) /// <summary> /// 암호화하기 /// </summary> /// <param name="source">소스 문자열</param> /// <param name="password">패스워드</param> /// <param name="salt">솔트</param> /// <returns>암호화 바이트 배열</returns> private static byte[] Encrypt(string source, string password, string salt) { UTF8Encoding encoding = new UTF8Encoding(); byte[] sourceByteArray = encoding.GetBytes(source); return EncryptOrDecrypt(password, sourceByteArray, salt, true); } #endregion #region 복호화하기 - Decrypt(sourceByteArray, password, salt) /// <summary> /// 복호화하기 /// </summary> /// <param name="sourceByteArray">소스 바이트 배열</param> /// <param name="password">패스워드</param> /// <param name="salt">솔트</param> /// <returns>복호화 문자열</returns> private static string Decrypt(byte[] sourceByteArray, string password, string salt) { byte[] targetByteArray = EncryptOrDecrypt(password, sourceByteArray, salt, false); UTF8Encoding encoding = new UTF8Encoding(); return new string(encoding.GetChars(targetByteArray)); } #endregion } } |
▶ Program.cs
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using System; namespace TestProject { /// <summary> /// 프로그램 /// </summary> class Program { //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Private #region 프로그램 시작하기 - Main() /// <summary> /// 프로그램 시작하기 /// </summary> private static void Main() { string plainText = "무궁화 꽃이 피었습니다."; string password = "test"; string salt = SecurityHelper.GetRandomSalt(); string textEncrypted = SecurityHelper.EncryptToString(plainText, password, salt); string textDecrypted = SecurityHelper.DecryptFromString(textEncrypted, password, salt); Console.WriteLine($"평문 : {plainText}"); Console.WriteLine($"패스워드 : {password}"); Console.WriteLine($"솔트 : {salt}"); Console.WriteLine($"암호문 : {textEncrypted}"); Console.WriteLine($"복호문 : {textDecrypted}"); } #endregion } } |
