CTF Challenge - CSR

Question

Hello there.

I’m currently working on the 'CSR' CTF challenge and would really appreciate some clarification.

Each time I try to collect my flag, I get this message: 'Now we need the sha256 signature of "5970554". Provide the resulting signature encoded in base64.' The number changes every time, and I’m not sure what it refers to or how to generate the correct response. Could you maybe provide some guidance or useful tips?

Thanks in Advance.

Answer 1

You have to do what the message says. You create a signature over the given number with your private key and encode it in base64.

To create the signature I used the python package called cryptography.

https://cryptography.io/en/latest/

Comments

Some additional Info: Your certificate contains a public key and by signing some message (the number) with the corresponding private key, you prove that it is your certificate.

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Totally forgot: Thank you very much for the answer it pretty much helped me