如何在 .net 中使用 Microsoft 的 TPM 庫加密我的消息

Question

我想用 TPM 加密和解密我的消息。 我使用微軟的 TSS-Library。 可以在此處找到文檔（包括示例）： https://github.com/microsoft/TSS.MSR/tree/master/TSS.NET
這是我的代碼片段：

public byte[] encryptData(byte[] message)
    {
      TpmHandle handle = new TpmHandle();
      byte[] keyAuth = new byte[] { 1, 2, 3 };
      SigSchemeRsassa scheme = new SigSchemeRsassa(TpmAlgId.Rsa);
      byte[] label = Encoding.Unicode.GetBytes("Label");
      return Tpm[keyAuth].RsaEncrypt(handle, message, scheme,label);
    }

錯誤是：

命令 RsaEncrypt 返回錯誤 {Value}。 詳細信息：[Code=TpmRc.Value]、[RawCode=0x184,388] [ErrorEntity=Handle]、[ParmNum=1]

我從我的簽名方法（在樣本中找到）修改了我的代碼。 我剛剛添加了我自己的 SignatureData 類，它存儲來自 CreatePrimary() 的 output 信息：（我在這個方法中遇到了同樣的錯誤以及錯誤的 authValue，但現在它工作了）

public void Sign(string message)
    {
      AuthValue ownerAuth = new AuthValue();
      signatureData = new TpmSignatureData();           
      //Transform Message in byte-form
      signatureData.ByteMessage = Encoding.Unicode.GetBytes(message);
      //create keyTepmplate
      TpmPublic keyTemplate = new TpmPublic(TpmAlgId.Sha1, ObjectAttr.UserWithAuth | ObjectAttr.Sign |
        ObjectAttr.FixedParent | ObjectAttr.FixedTPM | ObjectAttr.SensitiveDataOrigin, null,                                    // No policy
        new RsaParms(new SymDefObject(), new SchemeRsassa(TpmAlgId.Sha1), 2048, 0), new Tpm2bPublicKeyRsa());
      byte[] keyAuth = new byte[] { 1, 2, 3 };

      #region Temporary Variables
      TpmPublic tpmPublic;
      CreationData creationData;
      byte[] creationHash;
      TkCreation creationTicket;
      #endregion
      //Create keyHandle based on keyTemplate
      TpmHandle keyHandl = Tpm[ownerAuth].CreatePrimary(
                      TpmRh.Owner,                            // In the owner-hierarchy
                      new SensitiveCreate(keyAuth, null),     // With this auth-value
                      keyTemplate,                            // Describes key
                      null,                                   // Extra data for creation ticket
                      new PcrSelection[0],                    // Non-PCR-bound
                      out tpmPublic,                          // PubKey and attributes
                      out creationData, out creationHash, out creationTicket);    // Not used here
      //create Hash to be signed
      TpmHash digestToSign = TpmHash.FromData(TpmAlgId.Sha1, signatureData.ByteMessage);
      //Sign the hash-Value
      signatureData.signature = Tpm[keyAuth].Sign(keyHandl, digestToSign, null, TpmHashCheck.Null()) as SignatureRsassa;
    }

還有另一種加密方法。 您也可以使用 EncryptDecrypt-Method，但對我也不起作用。 我是否遺漏了一些簡單的東西，或者我是否需要完全更改我的代碼。 我想我的主要問題是 TpmHandle。 我不確定如何處理它。 任何幫助都會很棒。 提前致謝。

Answer 1

與此同時，我自己找到了解決方案。 問題是手柄。 如果我理解正確，您需要創建一個 rsa-primary-handle 然后修改句柄。 下面是兩個必要的方法：

public static TpmHandle CreateRsaPrimaryKey(Tpm2 tpm)
    {
      var sensCreate = new SensitiveCreate(new byte[] { 0xa, 0xb, 0xc }, null);
      TpmPublic parms = new TpmPublic(
                TpmAlgId.Sha1,
                ObjectAttr.Restricted | ObjectAttr.Decrypt | ObjectAttr.FixedParent | ObjectAttr.FixedTPM
                    | ObjectAttr.UserWithAuth | ObjectAttr.SensitiveDataOrigin,
                null,
                new RsaParms(
                    new SymDefObject(TpmAlgId.Aes, 128, TpmAlgId.Cfb),
                    new NullAsymScheme(),
                    2048,
                    0),
                new Tpm2bPublicKeyRsa());
      byte[] outsideInfo = Globs.GetRandomBytes(8);
      var creationPcr = new PcrSelection(TpmAlgId.Sha1, new uint[] { 0, 1, 2 });
      TpmPublic pubCreated;
      CreationData creationData;
      TkCreation creationTicket;
      byte[] creationHash;
      TpmHandle h = tpm.CreatePrimary(TpmRh.Owner, sensCreate, parms, outsideInfo, new PcrSelection[] { creationPcr },
                    out pubCreated, out creationData, out creationHash, out creationTicket);
      return h;
    }
    public static TpmHandle CreateSigningDecryptionKey(Tpm2 tpm, TpmHandle primHandle, out TpmPublic keyPublic)
    {
      TpmPublic keyInPublic = new TpmPublic(
          TpmAlgId.Sha1,
          ObjectAttr.Decrypt | ObjectAttr.Sign | ObjectAttr.FixedParent | ObjectAttr.FixedTPM
              | ObjectAttr.UserWithAuth | ObjectAttr.SensitiveDataOrigin,
          null,
          new RsaParms(
              new SymDefObject(),
              new NullAsymScheme(),
              2048, 0),
         new Tpm2bPublicKeyRsa());

      SensitiveCreate sensCreate = new SensitiveCreate(new byte[] { 1, 2, 3 }, null);
      CreationData keyCreationData;
      TkCreation creationTicket;
      byte[] creationHash;

      Console.WriteLine("Automatic authorization of a primary storage key.");

      //
      // An auth session is added automatically to authorize access to primHandle.
      //
      TpmPrivate keyPrivate = tpm.Create(primHandle,
                                         sensCreate,
                                         keyInPublic,
                                         null,
                                         new PcrSelection[0],
                                         out keyPublic,
                                         out keyCreationData,
                                         out creationHash,
                                         out creationTicket);

      TpmHandle keyHandle = null;

      Console.WriteLine("Strict mode.");

      //
      // Switch TPM object to the strict mode. (Note that this is a TSS.Net
      // specific piece of functionality, not a part of TPM 2.0 specification).
      //
      tpm._Behavior.Strict = true;

      //
      // No auth session is added automatically when TPM object is in strict mode.
      //
      tpm._ExpectError(TpmRc.AuthMissing)
         .Load(primHandle, keyPrivate, keyPublic);

      //
      // Now explicitly request an auth session of a desired type.
      // The actual auth value will be supplied by TSS.Net implicitly.
      //
      keyHandle = tpm[Auth.Default].Load(primHandle, keyPrivate, keyPublic);

      Console.WriteLine("Signing decryption key created.");

      //
      // Switch TPM object back to the normal mode.
      //
      tpm._Behavior.Strict = false;

      return keyHandle;
    }

我這樣調用構造函數中的方法：

handle = CreateSigningDecryptionKey(Tpm, CreateRsaPrimaryKey(Tpm), out keyPublic);

之后加密解密就很容易了。
加密：

return Tpm.RsaEncrypt(handle, data, new SchemeOaep(TpmAlgId.Sha1), null);

解密：

return Tpm.RsaDecrypt(handle, ciphertext, new SchemeOaep(TpmAlgId.Sha1), null);