将PEM编码的RSA公钥转换为AsymmetricKeyParameter [英] convert PEM encoded RSA public key to AsymmetricKeyParameter

问题描述

我正在尝试创建一种方法，该方法从PEM编码的 public 密钥构造一个 AsymmetricKeyParameter 。不幸的是， pemReader.ReadObject（）返回null。

这是私钥的可行解决方案：将PEM编码的RSA私钥转换为AsymmetricKeyParameter

此方法有什么问题？

 静态AsymmetricKeyParameter ReadPublicKeyFromPemEncodedString（string pemEncodedKey）
 {
 AsymmetricKeyParameter result = null; 
使用（var stringReader = new StringReader（pemEncodedKey））
 {
 var pemReader = new PemReader（stringReader）; 
 var pemObject = pemReader.ReadObject（）; // 空值！ 
结果=（（（AsymmetricCipherKeyPair）pemObject）.Public; 
} 
 
返回结果； 
} 
  

这里是我正在测试的PEM编码的公钥。我试过不加评论，也删除了SSH2。

  ---- BEGIN SSH2公钥---- 
点评： RSA的密钥-20170608 
 AAAAB3NzaC1yc2EAAAABJQAAAQEAk0AmagKx285Ufbri / OLC + f3WagL1Ho + DrYdD 
 SbuU7cJAq + uD9xGvvP9m2JavSP4wO9i9pB / cmCFMPoIj3oGJt1 / cnLb / U2juneOw 
 6Uo0N3F8TXdyXfZNAIPhq / jw0YfIypTFTTvFkKXfTArIwW / bQBW8 / dujFR8i5CxP 
 jRKRDOBEy0PPOLJDD0iUr9GX /小时/ EO4jQ7B / GszjhPiPx + gJCilaMY + jrSczjxpsK 
 OXzpZEdT1NqMrzgvIZPHYhQzAiw9vQzov3vezDwKgKcRrUixZ2B8uiEQNn7Wa2Qz 
 WF3vL + 6CGflFNYQcc0leDQBe86baYhCollouP4jfaH9KcMkYYw == 
 ---- END SSH2 PUBLIC KEY ---- 
  

解决方案

Bouncy castle只是不了解这种公钥（SSH2）格式（您可以通过查看如果您愿意，请使用 PemReader 的源代码）。不幸的是，我不知道如何在C＃中将其转换为适当的格式，但是您可以使用许多工具来做到这一点，例如使用ssh-keygen（也可以在gitbash中使用）或openssl。转换为PEM时，您的公钥将如下所示：

  ----- BEGIN RSA公钥----- 
 MIIBCAKCAQEAk0AmagKx285Ufbri / OLC + f3WagL1Ho + DrYdDSbuU7cJAq + uD9xGv 
 vP9m2JavSP4wO9i9pB / cmCFMPoIj3oGJt1 / cnLb / U2juneOw6Uo0N3F8TXdyXfZN 
 AIPhq / jw0YfIypTFTTvFkKXfTArIwW / bQBW8 / dujFR8i5CxPjRKRDOBEy0PPOLJD 
 D0iUr9GX /小时/ EO4jQ7B / GszjhPiPx + gJCilaMY + jrSczjxpsKOXzpZEdT1NqMrzgv 
 IZPHYhQzAiw9vQzov3vezDwKgKcRrUixZ2B8uiEQNn7Wa2QzWF3vL + 6CGflFNYQc 
 c0leDQBe86baYhCollouP4jfaH9KcMkYYwIBJQ == b 
-c 
 
 
您的当前代码将正确处理它，但有一点改动：
  var pemReader =新的PemReader（stringReader）; 
 var pemObject = pemReader.ReadObject（）; // 空值！ 
 //已经是AsymmetricKeyParameter 
结果=（（（AsymmetricKeyParameter）pemObject）; 
  
 
I am trying o create a method that constructs an AsymmetricKeyParameter from a PEM encoded public key.  Unfortunately, pemReader.ReadObject() return null.  

Here's a working solution for a private key: convert PEM encoded RSA private key to AsymmetricKeyParameter

What is wrong with this method?
static AsymmetricKeyParameter ReadPublicKeyFromPemEncodedString(string pemEncodedKey)
{
    AsymmetricKeyParameter result = null;
    using (var stringReader = new StringReader(pemEncodedKey))
    {
        var pemReader = new PemReader(stringReader);
        var pemObject = pemReader.ReadObject(); // null!
        result = ((AsymmetricCipherKeyPair)pemObject).Public;
    }

    return result;
}
Here is the PEM-encoded public key I am testing with.  I have tried without the comment and also removing SSH2.
---- BEGIN SSH2 PUBLIC KEY ----
Comment: "rsa-key-20170608"
AAAAB3NzaC1yc2EAAAABJQAAAQEAk0AmagKx285Ufbri/olc+f3WagL1Ho+DrYdD
SbuU7cJAq+uD9xGvvP9m2JavSP4wO9i9pB/cmCFMPoIj3oGJt1/cnLb/U2juneOw
6Uo0N3F8TXdyXfZNAIPhq/jw0YfIypTFTTvFkKXfTArIwW/bQBW8/dujFR8i5CxP
jRKRDOBEy0PPOLJDD0iUr9GX/h/EO4jQ7B/GszjhPiPx+gJCilaMY+jrSczjxpsK
OXzpZEdT1NqMrzgvIZPHYhQzAiw9vQzov3vezDwKgKcRrUixZ2B8uiEQNn7Wa2Qz
WF3vL+6CGflFNYQcc0leDQBe86baYhCollouP4jfaH9KcMkYYw==
---- END SSH2 PUBLIC KEY ----

解决方案
Bouncy castle just does not understand this format of public key (SSH2) (you can verify this by looking at source code of PemReader if you would like to). Unfortunately I don't know how to convert it to appropriate format in C#, but you can do that with many tools, for example with ssh-keygen (also available in gitbash for windows), or openssl. Your public key will look like this when converted to PEM:
-----BEGIN RSA PUBLIC KEY-----
MIIBCAKCAQEAk0AmagKx285Ufbri/olc+f3WagL1Ho+DrYdDSbuU7cJAq+uD9xGv
vP9m2JavSP4wO9i9pB/cmCFMPoIj3oGJt1/cnLb/U2juneOw6Uo0N3F8TXdyXfZN
AIPhq/jw0YfIypTFTTvFkKXfTArIwW/bQBW8/dujFR8i5CxPjRKRDOBEy0PPOLJD
D0iUr9GX/h/EO4jQ7B/GszjhPiPx+gJCilaMY+jrSczjxpsKOXzpZEdT1NqMrzgv
IZPHYhQzAiw9vQzov3vezDwKgKcRrUixZ2B8uiEQNn7Wa2QzWF3vL+6CGflFNYQc
c0leDQBe86baYhCollouP4jfaH9KcMkYYwIBJQ==
-----END RSA PUBLIC KEY-----
And it will be correctly handled by your current code, with a little change:
var pemReader = new PemReader(stringReader);
var pemObject = pemReader.ReadObject(); // null!
// it's already AsymmetricKeyParameter
result = ((AsymmetricKeyParameter)pemObject);


                        
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