I am doing an assignment where I have a CA (server) and a client that requests a certificate from the CA, this function works. The certificate is sent via tcp as bytes. The idea is that clients will share a session key, but before they do they need to verify each others certificates. I do not have two clients set up so I decided to verify the clients own certificate using the function I created, yet it somehow says the certificate is invalid even though I am verifying a certificate I just got from the CA:

Here is my function:

def verifyCert(certificate):

certificatetoRead = x509.load_pem_x509_certificate(certificate, default_backend())
public_key = certificatetoRead.public_key()

try:
    public_key.verify(
        certificatetoRead.signature,
        certificatetoRead.tbs_certificate_bytes,
        padding.PKCS1v15(),
        certificatetoRead.signature_hash_algorithm,
    )
    
    print("Certificate signature verified. It's legitimate.")
except Exception:
    print("Certificate signature verification failed. It may be tampered or invalid.")  

When the CA sends me the certificate I pass it to this verifyCert function, and becuase I’ve not done anything I’m expecting it to verify it and say it is legitimate but it says its tampered.

Could I please get help as to what I may be doing wrong.