/// <summary>
/// Initialises a new instance of the <see cref="MacStream" /> class.
/// </summary>
/// <param name="binding">Stream to write to or read from.</param>
/// <param name="writing">If set to <c>true</c>, writing; otherwise, reading.</param>
/// <param name="function">MAC function to instantiate.</param>
/// <param name="key">Cryptographic key to use in the MAC operation.</param>
/// <param name="salt">Cryptographic salt to use in the MAC operation, if any.</param>
/// <param name="output">Byte array where the finished MAC will be output to. Does not need to be initialised.</param>
/// <param name="config"></param>
/// <param name="nonce"></param>
/// <param name="closeOnDispose">If set to <c>true</c>, bound stream will be closed on dispose/close.</param>
public MacStream(Stream binding, bool writing, MacFunction function, out byte[] output, byte[] key,
byte[] salt = null,
byte[] config = null, byte[] nonce = null, bool closeOnDispose = true)
: this(binding, writing, function, key, salt, config, nonce, closeOnDispose)
{
output = _output;
}
/// <summary>
/// Creates a new <see cref="AuthenticationConfiguration" />.
/// HMAC, CMAC/OMAC1, or Poly1305 selection will use default basis primitives (BLAKE2B256, AES, and AES, respectively).
/// </summary>
/// <remarks>
/// The MAC configuration generated may be used with a MacStream,
/// e.g. package payload item authentication.
/// </remarks>
/// <param name="macFunctionEnum">MAC function.</param>
/// <param name="outputSize">Size of the output from the function in bytes.</param>
/// <returns>The authentication configuration as a <see cref="AuthenticationConfiguration" />.</returns>
public static AuthenticationConfiguration CreateAuthenticationConfiguration(MacFunction macFunctionEnum, out int outputSize)
{
if (Athena.Cryptography.MacFunctions[macFunctionEnum].OutputSize.HasValue == false)
{
// Either HMAC or CMAC/OMAC1 is being used.
switch (macFunctionEnum)
{
case MacFunction.Hmac:
return(CreateAuthenticationConfigurationHmac(DefaultHmacFunction, out outputSize));
case MacFunction.Cmac:
return(CreateAuthenticationConfigurationCmac(DefaultCmacCipher, out outputSize));
default:
throw new NotSupportedException();
}
}
if (macFunctionEnum == MacFunction.Poly1305)
{
outputSize = 16;
return(CreateAuthenticationConfigurationPoly1305(DefaultPoly1305BlockCipher));
}
outputSize = Athena.Cryptography.MacFunctions[macFunctionEnum].OutputSize.Value / 8;
return(CreateAuthConf(macFunctionEnum.ToString(), outputSize * 8, outputSize * 8, null, null));
}
/// <summary>
/// Creates a configuration for key confirmation using a MAC construction.
/// </summary>
/// <param name="macFunctionEnum">Hash function to use as basis of HMAC construction.</param>
/// <returns>A key confirmation configuration as a <see cref="AuthenticationConfiguration"/>.</returns>
public static AuthenticationConfiguration GenerateConfiguration(MacFunction macFunctionEnum)
{
int outputSize;
var config = AuthenticationConfigurationFactory.CreateAuthenticationConfiguration(macFunctionEnum, out outputSize);
return(config);
}
/// <summary>
/// Initialises a new instance of the <see cref="MacStream" /> class.
/// </summary>
/// <param name="binding">Stream to write to or read from.</param>
/// <param name="writing">If set to <c>true</c>, writing; otherwise, reading.</param>
/// <param name="function">MAC function to instantiate.</param>
/// <param name="key">Cryptographic key to use in the MAC operation.</param>
/// <param name="salt">Cryptographic salt to use in the MAC operation, if any.</param>
/// <param name="nonce"></param>
/// <param name="closeOnDispose">If set to <c>true</c>, bound stream will be closed on dispose/close.</param>
/// <param name="config"></param>
public MacStream(Stream binding, bool writing, MacFunction function, byte[] key, byte[] salt = null,
byte[] config = null, byte[] nonce = null, bool closeOnDispose = true)
{
Contract.Requires <ArgumentNullException>(binding != null);
Contract.Requires <ArgumentNullException>(key != null);
_streamBinding = binding;
Writing = writing;
_closeOnDispose = closeOnDispose;
_mac = AuthenticatorFactory.CreateMacPrimitive(function, key, salt, config, nonce);
_output = new byte[_mac.OutputSize];
_buffer = new byte[BufferSize];
}
protected void RunMacTest(MacFunction function, byte[] config = null, byte[] nonce = null, byte[] overrideKey = null, byte[] overrideSalt = null)
{
byte[] outputMac;
var sw = new Stopwatch();
using (var output = new MemoryStream((int)LargeBinaryFile.Length)) {
using (var macS = new MacStream(output, true, function, out outputMac, overrideKey ?? Key, overrideSalt ?? Salt, config, nonce, false)) {
sw.Start();
LargeBinaryFile.CopyTo(macS);
sw.Stop();
}
}
Debug.Print(outputMac.ToHexString());
Assert.Pass("{0:N0} ms ({1:N2} MB/s)", sw.ElapsedMilliseconds, ((double)LargeBinaryFile.Length / 1048576) / sw.Elapsed.TotalSeconds);
}
/// <summary>
/// Instantiates and initialises a Message Authentication Code (MAC) primitive.
/// If salt is used, it is applied as: salt||message, where || is concatenation.
/// </summary>
/// <param name="macEnum">MAC function to instantiate.</param>
/// <param name="key">Cryptographic key to use in the MAC operation.</param>
/// <param name="salt">Cryptographic salt to use in the MAC operation, if any.</param>
/// <param name="config">
/// Configuration for the function, where applicable. For example,
/// CMAC and HMAC use cipher and hash function names, repectively, encoded as UTF-8.
/// </param>
/// <param name="nonce">Nonce for the function, where applicable (rare, very specific) - null if N/A.</param>
/// <returns>
/// An MAC object deriving from <see cref="IMac" />.
/// </returns>
public static IMac CreateMacPrimitive(MacFunction macEnum, byte[] key, byte[] salt = null,
byte[] config = null, byte[] nonce = null)
{
IMac macObj;
switch (macEnum)
{
case MacFunction.Hmac:
if (config == null)
{
throw new ArgumentException("No hash function specified (encoded as UTF-8 bytes).", "config");
}
macObj = CreateHmacPrimitive(Encoding.UTF8.GetString(config).ToEnum <HashFunction>(), key, salt);
break;
case MacFunction.Cmac:
if (config == null)
{
throw new ArgumentException("No block cipher specified (encoded as UTF-8 bytes).", "config");
}
macObj = CreateCmacPrimitive(Encoding.UTF8.GetString(config).ToEnum <BlockCipher>(), key, salt);
break;
case MacFunction.Poly1305:
if (config != null && nonce == null)
{
throw new ArgumentException("No nonce/IV supplied for the block cipher.", "nonce");
}
macObj = CreatePoly1305Primitive(Encoding.UTF8.GetString(config).ToEnum <BlockCipher>(), key, nonce,
salt);
break;
default:
macObj = MacInstantiators[macEnum]();
macObj.Init(key);
if (salt.IsNullOrZeroLength() == false)
{
macObj.BlockUpdate(salt, 0, salt.Length);
}
break;
}
return(macObj);
}
/// <summary>
/// Instantiate a new MAC function engine.
/// </summary>
/// <param name="macIdentity">Identity of the MAC function.</param>
protected MacEngine(MacFunction macIdentity)
{
MacIdentity = macIdentity;
Key = null;
}
