C# 将证书字符串转换为X509证书

Question

我收到一个字符串，并希望使用 C# 将其转换为证书。我尝试了以下代码并收到“ The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.”错误：

 byte[] bytes = Convert.FromBase64String(((string[])request.Headers.GetValues("MY-Cert"))[0]);
                var cert = new X509Certificate2(bytes);

使用 C# 读取此类字符串的最佳方法是什么？

类似的问题在这里被问到，但是使用 C++

我收到以下格式的字符串：

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Answer 1

以下代码对我有用；

IEnumerable<string> headerValues;
var usercert = request.Headers.TryGetValues("MY-Cert", out headerValues);
var data = WebUtility.UrlDecode(((string[])headerValues)[0]);
byte[] bytes = Encoding.ASCII.GetBytes(data);
var cert = new X509Certificate2(bytes);
              

Answer 2

正如评论中指出的，您需要从 PEM 字符串中删除第一行和最后一行，然后将 Base64 字符串转换为X509Certificate2对象。

String certPemString = ((string[])request.Headers.GetValues("MY-Cert"))[0];
certPemString = certPemString
    .Replace("-----BEGIN CERTIFICATE-----",null)
    .Replace("-----END CERTIFICATE-----",null);
var cert = new X509Certificate2(Convert.FromBase64String(certPemString));