sign a request using SHA1 and private.key

[MaxPlatinum]

Hello, I have private key like:

string privateKey = @"-----BEGIN PRIVATE KEY-----
MIICd...............................
hqhPg==
-----END PRIVATE KEY-----";

And request like:

string request = "<?xml version=\"1.0\" encoding=\"windows-1251\"?><request>...............</request>";

.

I need to write code in C# based on Openssl commands:

openssl dgst –sha1 -out request.sign –sign private.key request.txt
openssl base64 -in request.sign –out request.enc

How to code these commands in C#? I tried a lot of exmaples and didnt get result. Could anyone code it please? How to read private key?

 

[MaxPlatinum]

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