/// <summary>
/// This function generates the private map F, which consists of u-1 layers.
/// <para>Each layer consists of oi polynomials where oi = vi[i+1]-vi[i].
/// The methods for the generation of the coefficients of these polynomials are called here.</para>
/// </summary>
private void GenerateF()
{
_layers = new MapLayer[_numLayers];
for (int i = 0; i < _numLayers; i++)
_layers[i] = new MapLayer(_VI[i], _VI[i + 1], _rngEngine);
}
/// <summary>
/// Reconstructs a public key from its <c>byte</c> array representation.
/// </summary>
///
/// <param name="KeyStream">An input stream containing an encoded key</param>
///
/// <exception cref="CryptoAsymmetricSignException">Thrown if the key could not be loaded</exception>
public RNBWPrivateKey(Stream KeyStream)
{
try
{
BinaryReader reader = new BinaryReader(KeyStream);
int len;
byte[] data;
len = reader.ReadInt32();
data = reader.ReadBytes(len);
_a1Inv = ArrayUtils.ToArray2x16(data);
len = reader.ReadInt32();
data = reader.ReadBytes(len);
_B1 = ArrayUtils.ToArray16(data);
len = reader.ReadInt32();
data = reader.ReadBytes(len);
_a2Inv = ArrayUtils.ToArray2x16(data);
len = reader.ReadInt32();
data = reader.ReadBytes(len);
_B2 = ArrayUtils.ToArray16(data);
len = reader.ReadInt32();
data = reader.ReadBytes(len);
_VI = ArrayUtils.ToArray32(data);
len = reader.ReadInt32();
_layers = new MapLayer[len];
for (int i = 0; i < _layers.Length; i++)
{
len = reader.ReadInt32();
data = reader.ReadBytes(len);
_layers[i] = new MapLayer(data);
}
}
catch (Exception ex)
{
throw new CryptoAsymmetricException("RNBWPrivateKey:CTor", "The RNBWPrivateKey could not be loaded!", ex);
}
}
/// <summary>
/// Initial operations before solving the Linear equation system
/// </summary>
///
/// <param name="Layer">The current layer for which a LES is to be solved</param>
/// <param name="Message">The message that should be signed</param>
///
/// <returns>The modified document needed for solving LES, (Y_ = A1^{-1}*(Y-b1)) linear map L1 = A1 x + b1</returns>
private short[] InitSign(MapLayer[] Layer, short[] Message)
{
// preparation: Modifies the document with the inverse of L1, tmp = Y - b1:
short[] tmpVec = new short[Message.Length];
tmpVec = _cptIf.AddVect(((RNBWPrivateKey)this._asmKey).B1, Message);
// Y_ = A1^{-1} * (Y - b1) :
short[] y = _cptIf.MultiplyMatrix(((RNBWPrivateKey)this._asmKey).InvA1, tmpVec);
// generates the vinegar vars of the first layer at random
for (int i = 0; i < Layer[0].VI; i++)
{
_X[i] = (short)_rndEngine.Next();
_X[i] = (short)(_X[i] & GF2Field.MASK);
}
return y;
}
/// <summary>
/// Initialize this class
/// </summary>
///
/// <param name="A1inv">The inverse of A1(the matrix part of the affine linear map L1) (n-v1 x n-v1 matrix)</param>
/// <param name="B1">Translation vector, part of the linear affine map L1</param>
/// <param name="A2inv">The inverse of A2(the matrix part of the affine linear map L2) (n x n matrix)</param>
/// <param name="B2">Translation vector, part of the linear affine map L2</param>
/// <param name="Vi">The number of Vinegar-variables per layer</param>
/// <param name="Layers">The polynomials with their coefficients of private map F</param>
internal RNBWPrivateKey(short[][] A1inv, short[] B1, short[][] A2inv, short[] B2, int[] Vi, MapLayer[] Layers)
{
_a1Inv = A1inv;
_B1 = B1;
_a2Inv = A2inv;
_B2 = B2;
_VI = Vi;
_layers = Layers;
}
