Portable Class Library (PCL) Contrib - Cryptography
-
12-12-2019 - |
Question
I want to use the cryptography in the Portable Class Library Contrib project on codeplex but have not found any documentation on how I can use it.
I want to create a wrapper class with Encrypt
and Decrypt
methods inside it and I want this wrapper class to exist in a portable class library. I have referenced Portable.Runtime
and Portable.Security.Cryptography
in this project. Is this correct?
I then want to use my wrapper inside a .NET, Windows Phone and Metro project. In these projects I reference my wrapper project, Portable.Runtime
, Portable.Security.Cryptography
and the corresponding Portable project i.e. Portable.Desktop
, Portable.Phone
or Portable.WindowsStore
. Is this correct?
I get conflicting namespace errors when I try to use my wrapper class however. This is the error and my wrapper class:
The type
System.Security.Cryptography.AesManaged
exists in bothC:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\Profile\Client\System.Core.dll
andC:\Downloads\PclContrib\bin\Debug\Portable.Security.Cryptography.dll
public sealed class SymmetricCryptography<T> where T : SymmetricAlgorithm, new()
{
private readonly T provider = new T();
private readonly UTF8Encoding utf8 = new UTF8Encoding();
private byte[] key;
private byte[] iv;
public byte[] Key
{
get { return this.key; }
}
public byte[] IV
{
get { return this.iv; }
}
public SymmetricCryptography()
{
this.key = this.provider.Key;
this.iv = this.provider.IV;
}
public SymmetricCryptography(byte[] key, byte[] iv)
{
this.key = key;
this.iv = iv;
}
public SymmetricCryptography(string password, string salt)
{
Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes(password, this.utf8.GetBytes(salt));
this.key = deriveBytes.GetBytes(this.provider.KeySize >> 3);
this.iv = deriveBytes.GetBytes(16);
}
public SymmetricCryptography(string password, string salt, int iterations)
{
Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes(password, this.utf8.GetBytes(salt), iterations);
this.key = deriveBytes.GetBytes(this.provider.KeySize >> 3);
this.iv = deriveBytes.GetBytes(16);
}
public byte[] Encrypt(byte[] input)
{
return this.Encrypt(input, this.key, this.iv);
}
public byte[] Encrypt(byte[] input, byte[] key, byte[] iv)
{
return this.Transform(
input,
this.provider.CreateEncryptor(key, iv));
}
public byte[] Decrypt(byte[] input)
{
return this.Decrypt(input, this.key, this.iv);
}
public byte[] Decrypt(byte[] input, byte[] key, byte[] iv)
{
return this.Transform(
input,
this.provider.CreateDecryptor(key, iv));
}
public string Encrypt(string text)
{
return this.Encrypt(text, this.key, this.iv);
}
public string Encrypt(string text, byte[] key, byte[] iv)
{
byte[] output = this.Transform(
this.utf8.GetBytes(text),
this.provider.CreateEncryptor(key, iv));
return Convert.ToBase64String(output);
}
public string Decrypt(string text)
{
return this.Decrypt(text, this.key, this.iv);
}
public string Decrypt(string text, byte[] key, byte[] iv)
{
byte[] output = this.Transform(
Convert.FromBase64String(text),
this.provider.CreateDecryptor(key, iv));
return this.utf8.GetString(output, 0, output.Length);
}
public void Encrypt(Stream input, Stream output)
{
this.Encrypt(input, output, this.key, this.iv);
}
public void Encrypt(Stream input, Stream output, byte[] key, byte[] iv)
{
this.TransformStream(true, ref input, ref output, key, iv);
}
public void Decrypt(Stream input, Stream output)
{
this.Decrypt(input, output, this.key, this.iv);
}
public void Decrypt(Stream input, Stream output, byte[] key, byte[] iv)
{
this.TransformStream(false, ref input, ref output, key, iv);
}
private byte[] Transform(
byte[] input,
ICryptoTransform cryptoTransform)
{
byte[] result;
using (MemoryStream memoryStream = new MemoryStream())
{
using (CryptoStream cryptStream = new CryptoStream(
memoryStream,
cryptoTransform,
CryptoStreamMode.Write))
{
cryptStream.Write(input, 0, input.Length);
cryptStream.FlushFinalBlock();
memoryStream.Position = 0;
result = memoryStream.ToArray();
}
}
return result;
}
private void TransformStream(bool encrypt, ref Stream input, ref Stream output, byte[] key, byte[] iv)
{
// defensive argument checking
if (input == null)
{
throw new ArgumentNullException("input");
}
if (output == null)
{
throw new ArgumentNullException("output");
}
if (!input.CanRead)
{
throw new ArgumentException("Unable to read from the input Stream.", "input");
}
if (!output.CanWrite)
{
throw new ArgumentException("Unable to write to the output Stream.", "output");
}
// make the buffer just large enough for
// the portion of the stream to be processed
byte[] inputBuffer = new byte[input.Length - input.Position];
// read the stream into the buffer
input.Read(inputBuffer, 0, inputBuffer.Length);
// transform the buffer
byte[] outputBuffer = encrypt ? Encrypt(inputBuffer, key, iv)
: Decrypt(inputBuffer, key, iv);
// write the transformed buffer to our output stream
output.Write(outputBuffer, 0, outputBuffer.Length);
}
}
Solution 3
It turns out that my generic wrapper for the cryptography algorithms was causing a problem. PCL Contrib contains a class called SymmetricAlgorithm which is itself a wrapper for the real SymmetricAlgorithm. If I make my wrapper class non-generic it works like this:
public sealed class AesManagedSymmetricCryptography : SymmetricCryptography<AesManaged>
{
#region Constructors
public AesManagedSymmetricCryptography()
{
}
public AesManagedSymmetricCryptography(byte[] key, byte[] iv)
: base(key, iv)
{
}
public AesManagedSymmetricCryptography(string password, string salt)
: base(password, salt)
{
}
public AesManagedSymmetricCryptography(string password, string salt, int iterations)
: base(password, salt, iterations)
{
}
#endregion
}
OTHER TIPS
The docs are a little lacking, but I call this out in the FAQ:
Can I share the types from PclContrib with my platform-specific projects? No, not currently. While the types in PclContrib look and feel like their platform-specific counterparts, the runtime and compiler will see them as completely different types. While we have some ideas on how to make this work, this is a feature that we won't be looking at for the short term.
The following .net code works on Desktop implementation. First add references to Portable.Desktop and Portable.Security.Cryptography.ProtectedData
private void button2_Click(object sender, EventArgs e)
{
String encrypted = PCL.CentralClass.Encrypt("yo");
String decreypted = PCL.CentralClass.Decrypt(encrypted);
//PCL.CentralClass.
}
//https://pclcontrib.codeplex.com/documentation?FocusElement=Comment
//\Source\Portable.Security.Cryptography.ProtectedData\Security\Cryptography\ProtectedData.cs
static byte[] GetBytes(string str)
{
byte[] bytes = new byte[str.Length * sizeof(char)];
System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
return bytes;
}
static string GetString(byte[] bytes)
{
char[] chars = new char[bytes.Length / sizeof(char)];
System.Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
return new string(chars);
}
public static String Encrypt(String strEncrypt)
{
byte[] userData = GetBytes(strEncrypt);
byte[] optionalEntropy = null;
byte[] x = System.Security.Cryptography.ProtectedData.Protect(userData, optionalEntropy);
return GetString(x);
}
public static String Decrypt(String strDecrypt)
{
byte[] encryptedData = GetBytes(strDecrypt);
byte[] optionalEntropy = null;
byte[] x = System.Security.Cryptography.ProtectedData.Unprotect(encryptedData, optionalEntropy);
return GetString(x); ;
}