/// <summary>
/// Create an enveloped (encrypted and integrity protected) private area from a provided sensitive.
/// </summary>
/// <param name="iv"></param>
/// <param name="sens"></param>
/// <param name="nameHash"></param>
/// <param name="publicName"></param>
/// <param name="symWrappingAlg"></param>
/// <param name="symKey"></param>
/// <param name="parentNameAlg"></param>
/// <param name="parentSeed"></param>
/// <param name="f"></param>
/// <returns></returns>
public static byte[] CreatePrivateFromSensitive(
SymDefObject symWrappingAlg,
byte[] symKey,
byte[] iv,
Sensitive sens,
TpmAlgId nameHash,
byte[] publicName,
TpmAlgId parentNameAlg,
byte[] parentSeed,
TssObject.Transformer f = null)
{
// ReSharper disable once InconsistentNaming
byte[] tpm2bIv = Marshaller.ToTpm2B(iv);
Transform(tpm2bIv, f);
byte[] sensitive = sens.GetTpmRepresentation();
Transform(sensitive, f);
// ReSharper disable once InconsistentNaming
byte[] tpm2bSensitive = Marshaller.ToTpm2B(sensitive);
Transform(tpm2bSensitive, f);
byte[] encSensitive = SymCipher.Encrypt(symWrappingAlg, symKey, iv, tpm2bSensitive);
Transform(encSensitive, f);
byte[] decSensitive = SymCipher.Decrypt(symWrappingAlg, symKey, iv, encSensitive);
Debug.Assert(f != null || Globs.ArraysAreEqual(decSensitive, tpm2bSensitive));
var hmacKeyBits = CryptoLib.DigestSize(parentNameAlg) * 8;
byte[] hmacKey = KDF.KDFa(parentNameAlg, parentSeed, "INTEGRITY", new byte[0], new byte[0], hmacKeyBits);
Transform(hmacKey, f);
byte[] dataToHmac = Marshaller.GetTpmRepresentation(tpm2bIv,
encSensitive,
publicName);
Transform(dataToHmac, f);
byte[] outerHmac = CryptoLib.Hmac(parentNameAlg, hmacKey, dataToHmac);
Transform(outerHmac, f);
byte[] priv = Marshaller.GetTpmRepresentation(Marshaller.ToTpm2B(outerHmac),
tpm2bIv,
encSensitive);
Transform(priv, f);
return(priv);
}
/// <summary>
/// Calculate the session-key from the nonces and salt/bound values (if present)
/// </summary>
public void CalcSessionKey()
{
if (Salt == SaltNeeded)
{
Globs.Throw("Unencrypted salt value must be provided for the session" +
Handle.handle.ToString("X8"));
}
// Compute Handle.Auth in accordance with Part 1, 19.6.8.
if (Salt == null && BindObject == TpmRh.Null)
{
SessionKey = new byte[0];
return;
}
byte[] auth = Globs.TrimTrailingZeros(BindObject.Auth);
byte[] hmacKey = Globs.Concatenate(auth, Salt);
SessionKey = KDF.KDFa(AuthHash, hmacKey, "ATH", NonceTpm, NonceCaller,
TpmHash.DigestSize(AuthHash) * 8);
}
/// <summary>
/// Calculate the session-key from the nonces and salt/bound values (if present)
/// </summary>
internal void CalcSessionKey()
{
Debug.Assert(SessionKey == null, "Attempt to repeatedly calculate session key");
if (Salt == SaltNeeded)
{
Globs.Throw(string.Format("Unencrypted salt value must be provided for the session {0:x}", Handle.handle));
}
// Compute Handle.Auth in accordance with Part 1, 19.6.8.
if (Salt == null && BindObject == TpmRh.Null)
{
SessionKey = new byte[0];
return;
}
byte[] auth = Globs.TrimTrailingZeros(BindObject.Auth);
byte[] hmacKey = Globs.Concatenate(auth, Salt);
SessionKey = KDF.KDFa(AuthHash, hmacKey, "ATH", NonceTpm, NonceCaller,
TpmHash.DigestSize(AuthHash) * 8);
}
/// <summary>
/// Create an enveloped (encrypted and integrity protected) private area from a provided sensitive.
/// </summary>
/// <param name="iv"></param>
/// <param name="sens"></param>
/// <param name="nameHash"></param>
/// <param name="publicName"></param>
/// <param name="symWrappingAlg"></param>
/// <param name="symKey"></param>
/// <param name="parentNameAlg"></param>
/// <param name="parentSeed"></param>
/// <param name="f"></param>
/// <returns></returns>
public static byte[] CreatePrivateFromSensitive(
SymDefObject symWrappingAlg,
byte[] symKey,
byte[] iv,
Sensitive sens,
TpmAlgId nameHash,
byte[] publicName,
TpmAlgId parentNameAlg,
byte[] parentSeed)
{
// ReSharper disable once InconsistentNaming
byte[] tpm2bIv = Marshaller.ToTpm2B(iv);
byte[] sensitive = sens.GetTpmRepresentation();
// ReSharper disable once InconsistentNaming
byte[] tpm2bSensitive = Marshaller.ToTpm2B(sensitive);
byte[] encSensitive = SymmCipher.Encrypt(symWrappingAlg, symKey, iv, tpm2bSensitive);
byte[] decSensitive = SymmCipher.Decrypt(symWrappingAlg, symKey, iv, encSensitive);
var hmacKeyBits = CryptoLib.DigestSize(parentNameAlg) * 8;
byte[] hmacKey = KDF.KDFa(parentNameAlg, parentSeed, "INTEGRITY", new byte[0], new byte[0], hmacKeyBits);
byte[] dataToHmac = Marshaller.GetTpmRepresentation(tpm2bIv,
encSensitive,
publicName);
byte[] outerHmac = CryptoLib.HmacData(parentNameAlg, hmacKey, dataToHmac);
byte[] priv = Marshaller.GetTpmRepresentation(Marshaller.ToTpm2B(outerHmac),
tpm2bIv,
encSensitive);
return(priv);
}
public static byte[] Xor(byte[] data, TpmAlgId hashAlg, byte[] key, byte[] contextU, byte[] contextV)
{
byte[] mask = KDF.KDFa(hashAlg, key, "XOR", contextU, contextV, (uint)data.Length * 8);
byte[] encData = Xor(mask, data);
return(encData);
}
public static byte[] KdfThenXor(TpmAlgId hashAlg, byte[] key, byte[] contextU, byte[] contextV, byte[] data)
{
var mask = KDF.KDFa(hashAlg, key, "XOR", contextU, contextV, (uint)(data.Length * 8));
return(XorEngine.Xor(data, mask));
}
/// <summary>
/// Creates a duplication blob for the current key that can be Imported as a child
/// of newParent. Three forms are possible. GetPlaintextDuplicationBlob() allows
/// plaintext-import. This function enables duplication with and without an
/// inner wrapper (depending on whether innerWrapper is null)
/// </summary>
/// <param name="newParent"></param>
/// <param name="innerWrapper"></param>
/// <param name="encSecret"></param>
/// <returns></returns>
public TpmPrivate GetDuplicationBlob(
TpmPublic pubNewParent,
SymCipher innerWrapper,
out byte[] encSecret)
{
byte[] encSensitive;
if (innerWrapper == null)
{
// No inner wrapper
encSensitive = Marshaller.ToTpm2B(Sensitive.GetTpmRepresentation());
Transform(encSensitive);
}
else
{
byte[] sens = Marshaller.ToTpm2B(Sensitive.GetTpmRepresentation());
byte[] toHash = Globs.Concatenate(sens, GetName());
Transform(toHash);
byte[] innerIntegrity = Marshaller.ToTpm2B(CryptoLib.HashData(
Public.nameAlg, toHash));
byte[] innerData = Globs.Concatenate(innerIntegrity, sens);
Transform(innerData);
encSensitive = innerWrapper.Encrypt(innerData);
Transform(encSensitive);
}
byte[] seed;
SymDefObject symDef = GetSymDef(pubNewParent).Copy();
// TPM duplication procedures always use CFB mode
symDef.Mode = TpmAlgId.Cfb;
using (var swNewParent = AsymCryptoSystem.CreateFrom(pubNewParent))
{
switch (pubNewParent.type)
{
case TpmAlgId.Rsa:
// The seed should be the same size as the scheme hash
LastSeed =
seed = Globs.GetRandomBytes(
CryptoLib.DigestSize(swNewParent.OaepHash));
encSecret = swNewParent.EncryptOaep(seed, DuplicateEncodingParms);
break;
case TpmAlgId.Ecc:
EccPoint pubEphem;
seed = swNewParent.EcdhGetKeyExchangeKey(DuplicateEncodingParms,
pubNewParent.nameAlg,
out pubEphem);
encSecret = Marshaller.GetTpmRepresentation(pubEphem);
break;
default:
Globs.Throw <NotImplementedException>(
"GetDuplicationBlob: Unsupported algorithm");
encSecret = new byte[0];
return(new TpmPrivate());
}
}
Transform(seed);
Transform(encSecret);
byte[] symKey = KDF.KDFa(pubNewParent.nameAlg, seed, "STORAGE",
Public.GetName(), new byte[0], symDef.KeyBits);
Transform(symKey);
byte[] dupSensitive;
using (SymCipher enc2 = SymCipher.Create(symDef, symKey))
{
if (enc2 == null)
{
return(null);
}
dupSensitive = enc2.Encrypt(encSensitive);
}
Transform(dupSensitive);
var npNameNumBits = CryptoLib.DigestSize(pubNewParent.nameAlg) * 8;
byte[] hmacKey = KDF.KDFa(pubNewParent.nameAlg, seed, "INTEGRITY",
new byte[0], new byte[0], npNameNumBits);
byte[] outerDataToHmac = Globs.Concatenate(dupSensitive, Public.GetName());
Transform(outerDataToHmac);
byte[] outerHmac = Marshaller.ToTpm2B(CryptoLib.Hmac(pubNewParent.nameAlg,
hmacKey, outerDataToHmac));
Transform(outerHmac);
byte[] dupBlob = Globs.Concatenate(outerHmac, dupSensitive);
Transform(dupBlob);
return(new TpmPrivate(dupBlob));
}
/// <summary>
/// Create activation blobs that can be passed to ActivateCredential. Two
/// blobs are returned:
/// 1) encryptedSecret - symmetric key cfb-symmetrically encrypted with the
/// enveloping key;
/// 2) credentialBlob - the enveloping key OEAP (RSA) encrypted by the public
/// part of this key. This is the return value of this
/// function
/// </summary>
/// <param name="secret"></param>
/// <param name="nameOfKeyToBeActivated"></param>
/// <param name="encryptedSecret"></param>
/// <returns>CredentialBlob (</returns>
public IdObject CreateActivationCredentials(byte[] secret,
byte[] nameOfKeyToBeActivated,
out byte[] encryptedSecret)
{
byte[] seed, encSecret;
switch (type)
{
case TpmAlgId.Rsa:
// The seed should be the same size as the name algorithmdigest
seed = Globs.GetRandomBytes(CryptoLib.DigestSize(nameAlg));
encSecret = EncryptOaep(seed, ActivateEncodingParms);
break;
case TpmAlgId.Ecc:
EccPoint ephemPubPt;
seed = EcdhGetKeyExchangeKey(ActivateEncodingParms, out ephemPubPt);
encSecret = Marshaller.GetTpmRepresentation(ephemPubPt);
break;
default:
Globs.Throw <NotImplementedException>(
"CreateActivationCredentials: Unsupported algorithm");
encryptedSecret = new byte[0];
return(null);
}
Transform(seed);
Transform(encSecret);
var cvx = new Tpm2bDigest(secret);
byte[] cvTpm2B = Marshaller.GetTpmRepresentation(cvx);
Transform(cvTpm2B);
SymDefObject symDef = TssObject.GetSymDef(this);
byte[] symKey = KDF.KDFa(nameAlg, seed, "STORAGE",
nameOfKeyToBeActivated, new byte[0], symDef.KeyBits);
Transform(symKey);
byte[] encIdentity;
// TPM only uses CFB mode in its command implementations
var sd = symDef.Copy();
sd.Mode = TpmAlgId.Cfb;
using (var sym = SymCipher.Create(sd, symKey))
{
// Not all keys specs are supported by SW crypto
if (sym == null)
{
encryptedSecret = null;
return(null);
}
encIdentity = sym.Encrypt(cvTpm2B);
}
Transform(encIdentity);
var hmacKeyBits = CryptoLib.DigestSize(nameAlg);
byte[] hmacKey = KDF.KDFa(nameAlg, seed, "INTEGRITY",
new byte[0], new byte[0], hmacKeyBits * 8);
Transform(hmacKey);
byte[] outerHmac = CryptoLib.Hmac(nameAlg, hmacKey,
Globs.Concatenate(encIdentity, nameOfKeyToBeActivated));
Transform(outerHmac);
encryptedSecret = encSecret;
return(new IdObject(outerHmac, encIdentity));
}
/// <summary>
/// Creates a duplication blob for the current key that can be Imported as a child
/// of newParent. Three forms are possible. GetPlaintextDuplicationBlob() allows
/// plaintext-import. This function enables duplication with and without an
/// inner wrapper (depending on whether innerWrapper is null)
/// </summary>
/// <param name="newParent"></param>
/// <param name="innerWrapper"></param>
/// <param name="encryptedWrappingKey"></param>
/// <returns></returns>
public TpmPrivate GetDuplicationBlob(
TpmPublic newParent,
SymmCipher innerWrapper,
out byte[] encryptedWrappingKey)
{
byte[] encSensitive;
if (innerWrapper == null)
{
// No inner wrapper
encSensitive = Marshaller.ToTpm2B(sensitivePart.GetTpmRepresentation());
}
else
{
byte[] sens = Marshaller.ToTpm2B(sensitivePart.GetTpmRepresentation());
byte[] toHash = Globs.Concatenate(sens, GetName());
byte[] innerIntegrity = Marshaller.ToTpm2B(CryptoLib.HashData(publicPart.nameAlg, toHash));
byte[] innerData = Globs.Concatenate(innerIntegrity, sens);
encSensitive = innerWrapper.Encrypt(innerData);
}
byte[] seed, encSecret;
SymDefObject symDef = GetSymDef(newParent);
using (AsymCryptoSystem newParentPubKey = AsymCryptoSystem.CreateFrom(newParent))
{
switch (newParent.type)
{
case TpmAlgId.Rsa:
// The seed should be the same size as the symmKey
seed = Globs.GetRandomBytes((symDef.KeyBits + 7) / 8);
encSecret = newParentPubKey.EncryptOaep(seed, DuplicateEncodingParms);
break;
case TpmAlgId.Ecc:
EccPoint pubEphem;
seed = newParentPubKey.EcdhGetKeyExchangeKey(DuplicateEncodingParms,
newParent.nameAlg,
out pubEphem);
encSecret = Marshaller.GetTpmRepresentation(pubEphem);
break;
default:
Globs.Throw <NotImplementedException>("GetDuplicationBlob: Unsupported algorithm");
encryptedWrappingKey = new byte[0];
return(new TpmPrivate());
}
}
encryptedWrappingKey = encSecret;
byte[] symKey = KDF.KDFa(newParent.nameAlg, seed, "STORAGE", publicPart.GetName(), new byte[0], symDef.KeyBits);
byte[] dupSensitive;
using (SymmCipher enc2 = SymmCipher.Create(symDef, symKey))
{
dupSensitive = enc2.Encrypt(encSensitive);
}
var npNameNumBits = CryptoLib.DigestSize(newParent.nameAlg) * 8;
byte[] hmacKey = KDF.KDFa(newParent.nameAlg, seed, "INTEGRITY", new byte[0], new byte[0], npNameNumBits);
byte[] outerDataToHmac = Globs.Concatenate(dupSensitive, publicPart.GetName());
byte[] outerHmac = Marshaller.ToTpm2B(CryptoLib.HmacData(newParent.nameAlg, hmacKey, outerDataToHmac));
byte[] dupBlob = Globs.Concatenate(outerHmac, dupSensitive);
return(new TpmPrivate(dupBlob));
}
/// <summary>
/// Create activation blobs that can be passed to ActivateCredential. Two blobs are returned -
/// (a) - encryptedSecret - is the symmetric key cfb-symmetrically encrypted with an enveloping key
/// (b) credentialBlob (the return value of this function) - is the enveloping key OEAP (RSA) encrypted
/// by the public part of this key.
/// </summary>
/// <param name="secret"></param>
/// <param name="nameAlgId"></param>
/// <param name="nameOfKeyToBeActivated"></param>
/// <param name="encryptedSecret"></param>
/// <returns>CredentialBlob (</returns>
public byte[] CreateActivationCredentials(
byte[] secret,
TpmAlgId nameAlgId,
byte[] nameOfKeyToBeActivated,
out byte[] encryptedSecret)
{
byte[] seed, encSecret;
switch (type)
{
case TpmAlgId.Rsa:
// The seed should be the same size as the symmKey
seed = Globs.GetRandomBytes((CryptoLib.DigestSize(nameAlg) + 7) / 8);
encSecret = EncryptOaep(seed, ActivateEncodingParms);
break;
case TpmAlgId.Ecc:
EccPoint pubEphem;
seed = EcdhGetKeyExchangeKey(ActivateEncodingParms, nameAlg, out pubEphem);
encSecret = Marshaller.GetTpmRepresentation(pubEphem);
break;
default:
Globs.Throw <NotImplementedException>("CreateActivationCredentials: Unsupported algorithm");
encryptedSecret = new byte[0];
return(new byte[0]);
}
Transform(seed);
Transform(encSecret);
var cvx = new Tpm2bDigest(secret);
byte[] cvTpm2B = Marshaller.GetTpmRepresentation(cvx);
Transform(cvTpm2B);
SymDefObject symDef = TssObject.GetSymDef(this);
byte[] symKey = KDF.KDFa(nameAlg, seed, "STORAGE", nameOfKeyToBeActivated, new byte[0], symDef.KeyBits);
Transform(symKey);
byte[] encIdentity;
using (SymmCipher symm2 = SymmCipher.Create(symDef, symKey))
{
encIdentity = symm2.Encrypt(cvTpm2B);
}
Transform(encIdentity);
var hmacKeyBits = CryptoLib.DigestSize(nameAlg);
byte[] hmacKey = KDF.KDFa(nameAlg, seed, "INTEGRITY", new byte[0], new byte[0], hmacKeyBits * 8);
Transform(hmacKey);
byte[] outerHmac = CryptoLib.HmacData(nameAlg,
hmacKey,
Globs.Concatenate(encIdentity, nameOfKeyToBeActivated));
Transform(outerHmac);
byte[] activationBlob = Globs.Concatenate(
Marshaller.ToTpm2B(outerHmac),
encIdentity);
Transform(activationBlob);
encryptedSecret = encSecret;
return(activationBlob);
}