/// <summary> /// Get an ECDH key exchange key (one pass ephemeral) and the public key of /// the ephemeral key using ECDH with encodingParms as input to the KDF (ECC only). /// </summary> /// <param name="encodingParms"></param> /// <param name="pubEphem"></param> /// <returns></returns> public byte[] EcdhGetKeyExchangeKey(byte[] encodingParms, out EccPoint ephemPubPt) { using (AsymCryptoSystem encryptor = AsymCryptoSystem.CreateFrom(this)) { return(encryptor.EcdhGetKeyExchangeKey(encodingParms, nameAlg, out ephemPubPt)); } }
/// <summary> /// Get an ECDH key exchange key (one pass ephemeral) and the public key of the ephemeral /// key using ECDH with encodingParms as input to the KDF (ECC only) /// </summary> /// <param name="encodingParms"></param> /// <param name="decryptKeyNameAlg"></param> /// <param name="pubEphem"></param> /// <returns></returns> public byte[] EcdhGetKeyExchangeKey(byte[] encodingParms, TpmAlgId decryptKeyNameAlg, out EccPoint pubEphem) { using (AsymCryptoSystem encryptor = AsymCryptoSystem.CreateFrom(this)) { return(encryptor.EcdhGetKeyExchangeKey(encodingParms, decryptKeyNameAlg, out pubEphem)); } }
/// <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)); }