public KdfResult Kdf(KdfParameterTwoStep param, BitString fixedInfo)
{
var result = _kdfVisitor.Kdf(param, fixedInfo);
var dkmBytesLen = result.DerivedKey.BitLength.CeilingDivide(BitString.BITSINBYTE);
// Modify a random byte within DKM
result.DerivedKey[_random.GetRandomInt(0, dkmBytesLen)] += 2;
return(result);
}
public void ShouldKdf()
{
var twoStepParam = new KdfParameterTwoStep()
{
L = 256,
Salt = new BitString(128),
Z = new BitString(128),
CounterLen = 8,
CounterLocation = CounterLocations.AfterFixedData,
KdfMode = KdfModes.Counter,
MacMode = MacModes.HMAC_SHA224,
};
var dkm = _kdfVisitor.Kdf(twoStepParam, new BitString(128));
Assert.AreEqual("EB9436CDC0C6FBC168A3BDE32929C104C2E4F4C1DEA2CA3485A7799E49870E0C", dkm.DerivedKey.ToHex());
}
public KdfResult Kdf(KdfParameterTwoStep param, BitString fixedInfo)
{
var zBytesLen = param.Z.BitLength.CeilingDivide(BitString.BITSINBYTE);
var modifiedParam = new KdfParameterTwoStep()
{
L = param.L,
Salt = param.Salt,
Z = param.Z.GetDeepCopy(),
FixedInfoPattern = param.FixedInfoPattern,
FixedInputEncoding = param.FixedInputEncoding,
MacMode = param.MacMode,
KdfMode = param.KdfMode,
Iv = param.Iv,
CounterLocation = param.CounterLocation,
CounterLen = param.CounterLen
};
// Modify a random byte within Z
modifiedParam.Z[_random.GetRandomInt(0, zBytesLen)] += 2;
return(_kdfVisitor.Kdf(modifiedParam, fixedInfo));
}
public KdfResult Kdf(KdfParameterTwoStep param, BitString fixedInfo)
{
IMac randomnessExtractionMac = null;
MacModes keyExpansionMacMode = param.MacMode;
switch (param.MacMode)
{
case MacModes.CMAC_AES128:
randomnessExtractionMac = _cmacFactory.GetCmacInstance(CmacTypes.AES128);
break;
case MacModes.CMAC_AES192:
randomnessExtractionMac = _cmacFactory.GetCmacInstance(CmacTypes.AES192);
keyExpansionMacMode = MacModes.CMAC_AES128;
break;
case MacModes.CMAC_AES256:
randomnessExtractionMac = _cmacFactory.GetCmacInstance(CmacTypes.AES256);
keyExpansionMacMode = MacModes.CMAC_AES128;
break;
case MacModes.HMAC_SHA1:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA1, DigestSizes.d160));
break;
case MacModes.HMAC_SHA224:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA2, DigestSizes.d224));
break;
case MacModes.HMAC_SHA256:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA2, DigestSizes.d256));
break;
case MacModes.HMAC_SHA384:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA2, DigestSizes.d384));
break;
case MacModes.HMAC_SHA512:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA2, DigestSizes.d512));
break;
case MacModes.HMAC_SHA_d512t224:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA2, DigestSizes.d512t224));
break;
case MacModes.HMAC_SHA_d512t256:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA2, DigestSizes.d512t256));
break;
case MacModes.HMAC_SHA3_224:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA3, DigestSizes.d224));
break;
case MacModes.HMAC_SHA3_256:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA3, DigestSizes.d256));
break;
case MacModes.HMAC_SHA3_384:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA3, DigestSizes.d384));
break;
case MacModes.HMAC_SHA3_512:
randomnessExtractionMac =
_hmacFactory.GetHmacInstance(new HashFunction(ModeValues.SHA3, DigestSizes.d512));
break;
default:
throw new ArgumentException($"Invalid {nameof(MacModes)} provided to KdfVisitor.");
}
// Randomness extraction (step one)
var randomnessExtraction = randomnessExtractionMac.Generate(param.Salt, param.Z);
// Key Expansion (step two)
var kdf = _kdfTwoStepFactory.GetKdfInstance(
param.KdfMode,
keyExpansionMacMode,
param.CounterLocation,
param.CounterLen);
return(new KdfResult(kdf.DeriveKey(randomnessExtraction.Mac, fixedInfo, param.L, param.Iv, 0).DerivedKey));
}
