X509 Certificate format

Question

When I do X509Certificate2 x509 = new X509Certificate2(certificateFile); what format does the certificate need to be in?

I have a private key:

-----BEGIN RSA PRIVATE KEY-----
......
-----END RSA PRIVATE KEY-----

and a certificate:

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
           ..............
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=IL, ST=SS, L=...., O=....., OU=....., CN=...../emailAddress=.....
        Validity
            Not Before: Mar 19 14:45:09 2013 GMT
            Not After : Mar 19 14:45:09 2014 GMT
        Subject: C=IL, ST=SS, L=...., O=....., OU=....., CN=...../emailAddress=.....
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    ...................
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier: 
                .........
            X509v3 Authority Key Identifier: 
                keyid:..........

            X509v3 Basic Constraints: 
                CA:TRUE
    Signature Algorithm: sha1WithRSAEncryption
        .....

Yet I am able to load neither using the C# code above. What am I missing?

What do you mean by "not able to load"? Are you getting an exception? Is there a stack trace? — Lynn Crumbling, Mar 20 '13 at 17:30
According to [the documentation](http://msdn.microsoft.com/en-us/library/ms148415.aspx) DER or Base64 formats are supported. — 500 - Internal Server Error, Mar 20 '13 at 17:52
Yes @500-InternalServerError Converted it to Base64, still get the same error. — user2191209, Mar 20 '13 at 18:31
[Other related answers](http://stackoverflow.com/questions/1345262/an-internal-error-occurred-when-loading-pfx-file-with-x509certificate2) suggest that at least files in the .PFX format should work. — 500 - Internal Server Error, Mar 20 '13 at 18:43

score 1 · Answer 1 · edited Dec 30 '17 at 16:23

-----BEGIN RSA PRIVATE KEY----- is a header for an RSA Private Key in PKCS#1 format (unencrypted). This format is used in Private Key PEM files.

The .NET Framework does not offer any ready-made method to directly export a Private Key in this format so you have to implement it yourself.

This document can help you - there is an example of decoding a RSA Private Key. Encoding is just the reverse operation.

X509 Certificate format

1 Answers1