/// <summary>
/// Generates a <code>ProofGenerationRandomData</code> instance using the internal RNG.
/// </summary>
/// <param name="numUndisclosed">Number of undisclosed attributes.</param>
/// <param name="numCommitted">Number of committed attributes.</param>
/// <param name="Zq">Field Zq</param>
/// <param name="isDeviceProtected">True if a toke is device-protected.</param>
/// <returns>A pregenerated set of random values.</returns>
internal static ProofGenerationRandomData Generate(int numUndisclosed, int numCommitted, FieldZq Zq, bool isDeviceProtected)
{
return new ProofGenerationRandomData(
Zq.GetRandomElement(false),
Zq.GetRandomElements(numUndisclosed, false),
isDeviceProtected ? Zq.GetRandomElement(false) : null,
numCommitted > 0 ? Zq.GetRandomElements(numCommitted, false) : null,
numCommitted > 0 ? Zq.GetRandomElements(numCommitted, false) : null
);
}
/// <summary>
/// Private constructor - takes and sets all fields.
/// </summary>
/// <param name="Gq">The group</param>
/// <param name="gd">The device generator</param>
/// <param name="Zq">The Field associated to the group <c>Gq</c></param>
/// <param name="xd">The xd.</param>
/// <param name="preGenWdPrime">The pre gen wd prime.</param>
VirtualDevice(Group Gq, GroupElement gd, FieldZq Zq, FieldZqElement xd, FieldZqElement preGenWdPrime)
{
if (xd != null && !Zq.IsElement(xd))
{
throw new ArgumentException("xd is not a valid Zq element");
}
this.Gd = gd;
this.Gq = Gq;
this.Zq = Zq;
this.xd = xd ?? this.Zq.GetRandomElement(true); // assign xd a random value if null
this.wdPrime = preGenWdPrime;
this.hd = this.Gd.Exponentiate(this.xd);
}
/// <summary>
/// Convert a base64 string to a FieldElement[] using a specific FieldZq object.
/// </summary>
/// <param name="encodedElements">The encoded string to convert.</param>
/// <param name="Zq">The fieldZq object to use.</param>
/// <returns>The converted object.</returns>
public static FieldZqElement[] ToFieldElementArray(this String[] encodedElements, FieldZq Zq)
{
if (encodedElements == null) return null;
FieldZqElement[] fieldElements = new FieldZqElement[encodedElements.Length];
for (int i = 0; i < encodedElements.Length; i++)
{
fieldElements[i] = encodedElements[i].ToFieldZqElement(Zq);
}
return fieldElements;
}
/// <summary>
/// Convert a base64 string to a FieldElement.
/// </summary>
/// <param name="encodedString">The encoded string to convert.</param>
/// <param name="Zq">The FieldZq object to which the encoded element belongs.</param>
/// <returns>The converted object.</returns>
public static FieldZqElement ToFieldZqElement(this String encodedString, FieldZq Zq)
{
if (encodedString == null) return null;
if (Zq == null) throw new ArgumentNullException("Zq");
return Zq.GetElement(Convert.FromBase64String(encodedString));
}
/// <summary>
/// Generates a new, random, private key.
/// </summary>
/// <remarks>The random number generator used is the one associated
/// with <c>iep</c> (indirectly, via the <c>IssuerParamters</c>).
/// </remarks>
public IDEscrowPrivateKey(IDEscrowParams iep)
{
UProveCrypto.Math.FieldZq F = iep.ip.Zq;
x = F.GetRandomElement(true);
}
internal static FieldZqElement GenerateChallengeForDevice(FieldZq zq, HashFunction hash, byte[] md, byte[] mdPrime)
{
hash.Hash(md);
hash.Hash(mdPrime);
return zq.GetElementFromDigest(hash.Digest);
}
