Molto probabilmente chi ha a che fare con i corsi di laurea scientifici e tecnologici, come me, ha preso atto della notizia che ChatGPT ha superato esami universitari in giurisprudenza ed economia con un pò, diciamo così, di sufficienza. Pensando "da noi non potrebbe mai succedere; figuriamoci". E' quello che ho pensato io.
Poi però ho fatto a ChatGPT qualche domanda di Reti di Calcolatori.
Ho quasi cambiato idea. "Quasi" perché nello scritto di Reti di Calcolatori faccio sempre esercizi. Pur non avendoli sottoposti a ChatGPT sono certo che questi esercizi non li sa risolvere. Ma alle "domande tipiche da orale" ha fornito risposte che mi hanno davvero stupefatto.
Riporto qui sotto solo un esempio di "dialogo", relativo a validazione di firma digitale e certificati auto-firmati. Risposte sostanzialmente corrette e pertinenti, molto più sintetiche e focalizzate di quelle che ricevo normalmente. E più rapide. Alla fine ha riconosciuto di essere stata (o stato?) inaccurata ed ha promesso di fare più attenzione in futuro.
Ho fatto anche una piccola interrogazione su domini e zone DNS ed anche in quel caso sono rimasto stupefatto.
Molto probabilmente supererebbe un orale.
(nota per i miei studenti ed ex studenti: il "dialogo" fa riferimento a fingerprint di chiavi pubbliche ed hash di firme digitali; io non ne parlo a lezione per semplicità, ciò che dice ChatGPT è corretto e corrisponde alla presentazione più diffusa dell'argomento)
bartoli.alberto@units.it: how do you check a digital signature?
ChatGPT: A digital signature is checked by verifying the authenticity of the signature and the integrity of the signed data. Here are the steps to check a digital signature:
- Obtain the public key of the signer: The public key of the signer is usually obtained through a trusted third party, such as a certificate authority (CA), or directly from the signer.
- Verify the signature: The signature is verified using the public key of the signer and a cryptographic algorithm, such as RSA or Elliptic Curve Digital Signature Algorithm (ECDSA). This process ensures that the signature was generated using the private key of the signer and that the data has not been tampered with.
- Verify the authenticity of the public key: The authenticity of the public key can be verified by checking if it is signed by a trusted CA or by checking its fingerprint against a trusted source.
- Check the integrity of the signed data: The integrity of the signed data is verified by checking that the hash of the original data matches the hash included in the signature.
By following these steps, you can be sure that the digital signature is genuine and that the signed data has not been tampered with.
bartoli.alberto@units.it: can you check a digital signature by using a self-signed certificate for attesting the public key of the signer?
ChatGPT: Yes, you can check a digital signature by using a self-signed certificate for attesting the public key of the signer, but it may not provide the same level of security as checking a digital signature with a certificate from a trusted third-party certificate authority (CA).
A self-signed certificate is one that is signed by the same entity that created it, rather than a trusted third-party CA. When using a self-signed certificate, there is no trusted third-party to verify the authenticity of the certificate and its associated public key.
In this case, the recipient must manually verify the authenticity of the self-signed certificate and the public key of the signer before checking the digital signature. This process can be time-consuming and prone to human error, and it does not provide the same level of security as checking a digital signature with a certificate from a trusted third-party CA.
In general, it is recommended to use a certificate from a trusted third-party CA for attesting the public key of the signer to provide the highest level of security when checking a digital signature.
bartoli.alberto@units.it: What do you mean by "manually"? I thought this check could be done with a computer
ChatGPT: Yes, you are correct. The process of checking a digital signature with a self-signed certificate can be automated and done using a computer.
When I said "manually", I meant that the recipient must obtain the self-signed certificate and public key of the signer and perform the necessary checks to verify the authenticity of the certificate and public key, which can be done through a program or software on a computer.
So, in short, the process of checking a digital signature with a self-signed certificate can be automated and done using a computer, but it requires the recipient to perform additional steps to verify the authenticity of the self-signed certificate and public key of the signer. bartoli.alberto@units.it
bartoli.alberto@units.it: Why did you say "the self-signed certificate and public key of the signer"? Isn't the public key contained in the certificate?
ChatGPT: Yes, you are correct. The public key of the signer is usually contained in the certificate. My mistake.
The self-signed certificate contains both the identity information of the signer and its public key, which is used to verify the digital signature. So, in this case, the recipient only needs to obtain and verify the authenticity of the self-signed certificate.
Thank you for pointing out this error. I will make sure to be more careful in my future responses.
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