CODEWITHSUNDEEP
c#encryptionrsax509
Fabi
Fabi

Reputation: 309

Using a X509 certificate for decryption

I have some data of an X509v3 certificate that is used at a central licensing station. My question is is the following amount of information enough for me to decrypt data using C# code? And additionally, how are the certificate properties imported into a project? Do I have to create a certificate file in order to go on?

Known to me are:

I do not have any certificate file. Excuse me if a similar question has already been answered, unfortunately I wasn't able to find one like mine.

Upvotes: 0

Views: 1651

Answers (2)

Ivan R.
Ivan R.

Reputation: 1915

This information is not enough. This data is a public key to encrypt data. RSAParameters

Upvotes: 2

Maarten Bodewes
Maarten Bodewes

Reputation: 93968

No, your data is not enough. First of all, this is all public data. It doesn't contain a private key. A private key is used for decryption or signature generation. A public key is used for encryption and signature verification.

The .NET API is peculiar in that you can seemingly use a certificate to decrypt. This is not really the case; the certificate and private key pair are seen as one; only if the private key is included then you can actually decrypt. Personally I see this as a minor design mistake.

In principle you could create a certificate given the information. Basically you would have to generate a certificate with the same information and then replace the issuer and signature fields.

This is however not for the weak of heart; I recommend a few years of experience before you even try. If any information is missing from the list above you won't get a valid certificate / signature, and you won't get any warning what is wrong, just a failure. You've got one advantage though; if the signature verifies or fingerprint is identical to the one you've got then you know that you've succeeded.

You would not be able to decrypt of course; the private key would still be missing.

Note that the signature is the 256 untitled bytes.

Upvotes: 3

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