public Stream DecryptedStream(Stream streamToDecrypt)
{
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
using (ICspProxy csp = CspFactory.GetProvider())
{
// Get the AES key from the stream
// The length will be the size of the RSA key which was used to encrypt
// the 256 bit AES key (assuming the RSA key is always larger than 256 bit).
byte[] encryptedKey = new byte[AsymmetricKeySize / 8];
byte[] decryptedKey;
streamToDecrypt.Read(encryptedKey, 0, encryptedKey.Length);
decryptedKey = csp.Decrypt(encryptedKey);
// Attempt to read IV from Stream
byte[] ivBytes = new byte[aesAlg.BlockSize / 8];
streamToDecrypt.Read(ivBytes, 0, ivBytes.Length);
// Set key and initialization vector
aesAlg.Key = decryptedKey;
aesAlg.IV = ivBytes;
// Create a decryptor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor();
CryptoStream cryptoStream = new CryptoStream(streamToDecrypt, decryptor, CryptoStreamMode.Read);
return(cryptoStream);
}
}
public string ToKeyFileString(bool publicOnly)
{
KeyFileStorage keyStorage;
byte[] temporaryCspBlob;
using (ICspProxy csp = CspFactory.GetProvider())
{
if (publicOnly)
{
temporaryCspBlob = csp.PublicKeyBlob;
}
else
{
temporaryCspBlob = csp.KeyBlob;
}
keyStorage = new KeyFileStorage
{
KeyMaterial = temporaryCspBlob,
ProviderType = GetType().ToString(),
ContainsPrivateKey = !publicOnly && !csp.IsPublicOnly
};
}
return(JsonConvert.SerializeObject(keyStorage));
}
public string ToKeyFileString(bool publicOnly)
{
KeyFileStorage keyStorage;
byte[] temporaryCspBlob;
using (ICspProxy csp = CspFactory.GetProvider())
{
if (publicOnly)
{
temporaryCspBlob = csp.PublicKeyBlob;
}
else
{
temporaryCspBlob = csp.KeyBlob;
}
keyStorage = new KeyFileStorage
{
KeyMaterial = temporaryCspBlob,
ProviderType = GetType().ToString(),
ContainsPrivateKey = !publicOnly && !csp.IsPublicOnly
};
}
/*
* using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
* {
* rsa.ImportCspBlob(CspBlob);
*
* if (publicOnly && !rsa.PublicOnly)
* {
* temporaryCspBlob = rsa.ExportCspBlob(false);
* }
* else
* {
* temporaryCspBlob = CspBlob;
* }
*
* keyStorage = new KeyFileStorage
* {
* KeyMaterial = temporaryCspBlob,
* ProviderType = GetType().ToString(),
* ContainsPrivateKey = !publicOnly && !rsa.PublicOnly
* };
* }
*/
return(JsonConvert.SerializeObject(keyStorage));
}
public Stream EncryptedStream(Stream streamToEncrypt)
{
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
using (ICspProxy csp = CspFactory.GetProvider())
{
// Set new key but retain randomized IV created during provider instantiation.
aesAlg.Key = GenerateRandomKey();
byte[] encryptedKey = csp.Encrypt(aesAlg.Key);
// Create an encryptor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor();
MemoryStream keyStream = new MemoryStream(encryptedKey);
MemoryStream ivStream = new MemoryStream(aesAlg.IV);
CryptoStream cryptoStream = new CryptoStream(streamToEncrypt, encryptor, CryptoStreamMode.Read);
return(new ConcatenatedStream(keyStream, ivStream, cryptoStream));
}
}
