8

I think you're not too far from a possible solution (aka using a modern KDF and effectively treating this like a password). However, there are some more considerations (which were already mentioned in comments): SSNs have very low entropy, which means that brute-force is an especially easy attack Since you need to find if the SSN has been used anywhere, ...


3

S/MIME and DKIM are totally independent from each other. S/MIME signature and encryption is applied by the sender (end user) while DKIM signatures are applied by the mail server of the senders domain. Similar DKIM is usually verified by the mail server of the receiving domain while S/MIME signature and encryption are verified by the final recipient - the ...


3

The use of the private key cannot reasonably be called “encrypting” since the security objective is to ensure authentication, not confidentiality. There can't be any encryption going on since all the information to reverse it is public. What you describe is a signature scheme, specifically a signature scheme with recovery since the same encoded message ...


2

You are talking about Kerckhoffs's principle. From the wikipedia page: Kerckhoffs's principle (also called Kerckhoffs's desideratum, assumption, axiom, doctrine or law) of cryptography was stated by Netherlands born cryptographer Auguste Kerckhoffs in the 19th century: A cryptosystem should be secure even if everything about the system, except ...


1

SSL is handled inside the applications (like browsers) themselves by using libraries like SChannel, Secure Transport, OpenSSL, NSS etc. This means only encrypted traffic enters or leaves the applications. Anybody wanting to get access to the plain traffic without being an active man in the middle would need to inject itself into the process of the running ...


1

Underneath the hood SFTP uses SSH but the same principles apply. Generally, it is impossible to derive the public key from the private key. Hence we're allowed to share/publish the public key without any fear of the private key being compromised. You will use your Private Key to authenticate yourself to ServerA, and ServerA uses your pre-loaded publickey to ...


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