OpenSSL X509Certificate2 Provider

Parses OpenSSL public and private key components and returns a X509Certificate2 with RSA/RSACryptoServiceProvider. (Based on http://www.jensign.com/opensslkey/opensslkey.cs (Archive Link))

Project	NuGet
OpenSSL.PrivateKeyDecoder
OpenSSL.PublicKeyDecoder
OpenSSL.X509Certificate2.Provider

Support for the following frameworks:

• .NET 2.0
• .NET 3.5
• .NET 4.5 and up
• .NET Standard 1.3 (also NET Core 1.1)
• .NET Standard 2.0 (also NET Core 2.0 and 2.1)

Support for decoding RSA Private Key, Private Key and Public Key.

Example

Generate public certificate + privatekey

Generate public certificate + privatekey using:

openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout private.key -out certificate_pub.crt

Code example 1 - decode private key into RSAParameters

If you just want to decode the private key into RSAParameters, use the following code:

string privateKeyText = File.ReadAllText("private.key");

IOpenSSLPrivateKeyDecoder decoder = new OpenSSLPrivateKeyDecoder();
RSAParameters parameters = decoder.DecodeParameters(privateKeyText);

// do something with the parameters ...

Code example 2 - decode private key into a RSACryptoServiceProvider

If you want to decode the private key into a RSACryptoServiceProvider, use the following code:

string privateKeyText = File.ReadAllText("private.key");

IOpenSSLPrivateKeyDecoder decoder = new OpenSSLPrivateKeyDecoder();
RSACryptoServiceProvider cryptoServiceProvider = decoder.Decode(privateKeyText);

// Example: sign the data
byte[] hello = new UTF8Encoding().GetBytes("Hello World");
byte[] hashValue = cryptoServiceProvider.SignData(hello, CryptoConfig.MapNameToOID("SHA256"));

// Example: use the PrivateKey from above for signing a JWT token using Jose.Jwt:
string token = Jose.JWT.Encode(payload, cryptoServiceProvider, JwsAlgorithm.RS256);

Code example 3 - Create a X509 certificate and add private key

string certificateText = File.ReadAllText("certificate_pub.crt");
string privateKeyText = File.ReadAllText("private.key");

ICertificateProvider provider = new CertificateFromFileProvider(certificateText, privateKeyText);
X509Certificate2 certificate = provider.Certificate;

// Example: use the PrivateKey from the certificate above for signing a JWT token using Jose.Jwt:
string token = Jose.JWT.Encode(payload, certificate.PrivateKey, JwsAlgorithm.RS256);

Code example 4 - decode openssl RSA public key into RSAParameters

If you just want to decode the rsa public key into RSAParameters, use the following code:

Export the public key from the private key with openssl

openssl rsa -in private.key -out public.key -pubout

string publicKeyText = File.ReadAllText("public.key");

IOpenSSLPublicKeyDecoder decoder = new OpenSSLPublicKeyDecoder();
RSAParameters parameters = decoder.DecodeParameters(publicKeyText);