Posts

• PhilipOchu USBeta, University ✭✭✭

  February 2016

  If your Platform specific project's version of .NET supports 3DES then you can write an abstraction that you expose to your PCL.

  See https://developer.xamarin.com/guides/xamarin-forms/dependency-service/ for examples

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• AdamP AUUniversity ✭✭✭✭✭

  February 2016

  @Maharshi.5212 - Here is an example of someone self implementing on Windows Phone 7 but should be easily enough implemented in PCL or at least natively per platform. https://gist.github.com/amrishodiq/1622737

  However if 3DES is just because of a personal preference or outdated security recommendations, AES is generally recommended over 3DES.

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• Maharshi.5212 USMember ✭✭

  February 2016

  Can i use the PCl crypto library in the normal asp.net app . The encryption is getting done in the server. My app needs to decrypt it.

  There is a code recipe i found in the PCl crypto library.

  byte[] keyMaterial;
  byte[] data;
  var provider = WinRTCrypto.SymmetricKeyAlgorithmProvider.OpenAlgorithm(SymmetricAlgorithm.AesCbcPkcs7);
  var key = provider.CreateSymmetricKey(keyMaterial);
  byte[] iv = null; // this is optional, but must be the same for both encrypting and decrypting
  byte[] cipherText = WinRTCrypto.CryptographicEngine.Encrypt(key, data, iv);
  byte[] plainText = WinRTCrypto.CryptographicEngine.Decrypt(key, cipherText, iv);

  Can i do it in a normal C# project?

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• Maharshi.5212 USMember ✭✭

  February 2016

  Can i use PCLcrypto in a normal c# application?

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• Maharshi.5212 USMember ✭✭

  March 2016

  Hi,
  I have written this code for pcl encryption .

  static class Program
  {
  static void Main(string[] args)
  {

          string data = "Examples";
  
          string key = "AAECAwQFBgcICQoLDA0ODw==";
          string cipherText = SymmetricEncrypt(data, key);
  
  
          string plainText= SymmetricDecrypt(cipherText, key);
      }
  
  
      private static string SymmetricDecrypt(this string cipherText, string key)
      {
          byte[] keyBuffer = Convert.FromBase64String(key);
          byte[] cipherTextBuffer = Convert.FromBase64String(cipherText);
  
          ISymmetricKeyAlgorithmProvider symmetricAlgorithm = WinRTCrypto.SymmetricKeyAlgorithmProvider.OpenAlgorithm(PCLCrypto.SymmetricAlgorithm.AesEcbPkcs7);
  
          var symmetricKey = symmetricAlgorithm.CreateSymmetricKey(keyBuffer);
          var decryptor = WinRTCrypto.CryptographicEngine.CreateDecryptor(symmetricKey);
          byte[] plainTextBuffer = decryptor.TransformFinalBlock(cipherTextBuffer, 0, cipherTextBuffer.Length);
          return Convert.ToBase64String(plainTextBuffer, 0, plainTextBuffer.Length);
      }
  
      public static string SymmetricEncrypt(this string plaintext, string key)
      {
          byte[] keyBuffer = Convert.FromBase64String(key);
          byte[] plainTextBuffer = Convert.FromBase64String(plaintext);
  
  
          ISymmetricKeyAlgorithmProvider symmetricAlgorithm = WinRTCrypto.SymmetricKeyAlgorithmProvider.OpenAlgorithm(PCLCrypto.SymmetricAlgorithm.AesEcbPkcs7);
  
          var symmetricKey = symmetricAlgorithm.CreateSymmetricKey(keyBuffer);
          var encryptor = WinRTCrypto.CryptographicEngine.CreateEncryptor(symmetricKey);
          byte[] cipherBuffer = encryptor.TransformFinalBlock(plainTextBuffer, 0, plainTextBuffer.Length);
          return Convert.ToBase64String(cipherBuffer);
      }
  
  }
  

  But I cannot change the length of the sample string. What shall i do in this scenario?

  2
• snaatan Member ✭

  June 2018

  This work for me ...

  public static string SymmetricEncrypt(this string plaintext)
  {
  string data = Convert.ToBase64String(Encoding.UTF8.GetBytes(plaintext));
  string key = "AAECAwQFBgcICQoLDA0ODw==";
  byte[] keyBuffer = Convert.FromBase64String(key);
  byte[] plainTextBuffer = Convert.FromBase64String(data);

          ISymmetricKeyAlgorithmProvider symmetricAlgorithm = WinRTCrypto.SymmetricKeyAlgorithmProvider.OpenAlgorithm(PCLCrypto.SymmetricAlgorithm.AesEcbPkcs7);
  
          var symmetricKey = symmetricAlgorithm.CreateSymmetricKey(keyBuffer);
          var encryptor = WinRTCrypto.CryptographicEngine.CreateEncryptor(symmetricKey);
          byte[] cipherBuffer = encryptor.TransformFinalBlock(plainTextBuffer, 0, plainTextBuffer.Length);
          return Convert.ToBase64String(cipherBuffer);
      }
  
  public static string SymmetricDecrypt(this string cipherText)
      {
          string key = "AAECAwQFBgcICQoLDA0ODw==";
          byte[] keyBuffer = Convert.FromBase64String(key);
          byte[] cipherTextBuffer = Convert.FromBase64String(cipherText);
  
          ISymmetricKeyAlgorithmProvider symmetricAlgorithm = WinRTCrypto.SymmetricKeyAlgorithmProvider.OpenAlgorithm(PCLCrypto.SymmetricAlgorithm.AesEcbPkcs7);
  
          var symmetricKey = symmetricAlgorithm.CreateSymmetricKey(keyBuffer);
          var decryptor = WinRTCrypto.CryptographicEngine.CreateDecryptor(symmetricKey);
          byte[] plainTextBuffer = decryptor.TransformFinalBlock(cipherTextBuffer, 0, cipherTextBuffer.Length);
          var test = Convert.FromBase64String(Convert.ToBase64String(plainTextBuffer, 0, plainTextBuffer.Length));
          string jsonBack = System.Text.Encoding.UTF8.GetString(test, 0, test.Length);
          return jsonBack;
      }
  

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