CngKey.Create 不支持请求的操作

Question

我正在尝试在 C# 程序集（目标 .NET 4.0）中（以编程方式）动态生成自签名证书，以用作生成其他证书的根 CA。证书不需要保存在 Windows 证书存储中，我会将其导出为文件。

通读this question (and in particular, @dthorpe's answer), I decided to give a try to CLR Security。

CLR Security 库在 CngKey class 上放置了一个扩展方法来生成自签名证书，但我无法成功创建 CngKey 的实例：

var key = CngKey.Create(CngAlgorithm.Sha1); //same with Sha256, Sha512 and MD5
//or
var key = CngKey.Create(CngAlgorithm.Sha1, null, new CngKeyCreationParameters()
{
    ExportPolicy = CngExportPolicies.AllowExport,
    KeyUsage = CngKeyUsages.AllUsages,
    KeyCreationOptions = CngKeyCreationOptions.MachineKey,
});

这些行中的任何一行都会引发异常：

System.Security.Cryptography.CryptographicException was unhandled
HResult=-2146893783
Message=The requested operation is not supported.

Source=System.Core  
StackTrace:  
  at System.Security.Cryptography.NCryptNative.CreatePersistedKey(SafeNCryptProviderHandle provider, String algorithm, String name, CngKeyCreationOptions options)  
  at System.Security.Cryptography.CngKey.Create(CngAlgorithm algorithm,  String keyName, CngKeyCreationParameters creationParameters)  
  at System.Security.Cryptography.CngKey.Create(CngAlgorithm algorithm)  
  at Tests.Program.Main(String[] args) at Program.cs:line 51

通过 SO 和互联网搜索，我检查了以下内容：

• 我是 运行 一个 Windows 7 盒子（因此它支持 MSDN 的 RPC）
• 在 Windows Server 2012 盒子上试过，同样的错误
• 该进程是 运行 管理员（因此无论如何它都可以访问所有证书存储）
• 服务 CNG Key Isolation 和 Remote Procedure Call (RPC) 是 运行

如有任何帮助，我们将不胜感激。

Answer 1

小题外话：在 google 搜索这个问题时发现 a site with HRESULT descriptions 和 SO 和 MSDN 上的便捷搜索工具（我只是 googled 为您 HRESULT代码 -2146893783)

---

我找到了 topic on MSDN which contains code failing with similar HRESULT, and the author provides a link to MSDN article about CNG:

NCRYPT_ALGORITHM_GROUP_PROPERTY L"Algorithm Group"
A null-terminated Unicode string that contains the name of the object's algorithm group. This property only applies to keys. The following identifiers are returned by the Microsoft key storage provider:

• NCRYPT_RSA_ALGORITHM_GROUP
  "RSA", The RSA algorithm group.
• NCRYPT_DH_ALGORITHM_GROUP
  "DH", The Diffie-Hellman algorithm group.
• NCRYPT_DSA_ALGORITHM_GROUP
  "DSA", The DSA algorithm group.
• NCRYPT_ECDSA_ALGORITHM_GROUP
  "ECDSA", The elliptic curve DSA algorithm group.
• NCRYPT_ECDH_ALGORITHM_GROUP
  "ECDH", The elliptic curve Diffie-Hellman algorithm group.

我还在 MSDN 上找到了一篇关于 CNG Key Storage Providers 的文章，其中包含类似的算法列表：

• Diffie-Hellman (DH)
  Secret agreement and key exchange, 512 to 4096 in 64-bit increments
• Digital Signature Algorithm (DSA) Signatures, 512 to 1024 in 64-bit increments
• Elliptic Curve Diffie-Hellman (ECDH) Secret agreement and key exchange, P256, P384, P521
• Elliptic Curve Digital Signature Algorithm (ECDSA) Signatures, P256, P384, P521
• RSA Asymmetric encryption and signing, 512 to 16384 in 64-bit increments

因此，正如您所说，您只尝试了 Sha1、Sha256、Sha512 和 MD5，也许您只需使用另一个 algorithm from list available？你可以找到上面提到的那些：

• RSA
• ECDsa
  • P256
  • P384
  • P521
• ECDiffieHellman
  • P256
  • P384
  • P521

Here other developers successfully created 其中之一并且能够导出它：

var cngKey = CngKey.Create(CngAlgorithm.ECDiffieHellmanP256, null,
    new CngKeyCreationParameters { ExportPolicy = CngExportPolicies.AllowPlaintextExport });