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I would only add that use-case is important to know as to whether a Certificate Authority (CA) is needed. If you are using CPanel for your own website and don't want to pay for an SSL cert, you can create a self-signed certificate, and then tell your browser to trust that public key. You are then acting as your own CA, essentially. Another case might be an ...


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The certificate makes sure that whoever you're talking to is who they claim they are. With TLS/SSL without certs you wouldn't notice if you're communicating with an impostor over an encrypted channel instead of whoever you're expecting to communicate with. This leads to so called man-in-the-middle attacks. You really should read this, if you're going to use ...


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The key you wrote down contains a mixed alphabetic and digit symbols because it is written in its hexadecimal representation: i.e. using symbols from 0 to 9 and from A to F. More on this topic on Wikipedia page. You can easily convert hexadecimal to decimal using software as python, sage, Pari/GP and many others. An online converter could be found here: ...


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Public-key cryptography is not sufficiently computationally burdensome to where other approaches must be used for authentication protocols. Note though that what you describe is not actually public-key based. The verification of the MAC requires Dave and Bob to both have a shared key. Also, note that a random component must be included in some manner in all ...


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I'll answer the related questions in order: No, because a ciphertext (generated from a key stream generated by a stream cipher) should be indistinguishable from random data, and a MAC should be as well. No, because #1 depends on the secret, and the secret was derived using a Diffie-Hellman key agreement algorithm, using the given curve. To know ...


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When you go from Affine to Jacobian, $X$ and $Y$ stay the same, and $Z$ is equal to $1$ Affine -> Jacobian: $(X',Y',Z') = (X,Y,1)$ Jacobian -> Affine: $(X',Y') = (\frac{X}{Z^2}, \frac{Y}{Z^3} )$


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Supersingular isogenies are a rather recent attempt at post quantum security. You will have a hard time finding an efficient and secure implementation, and even if you write one yourself, the algorithms have not yet seen that much cryptanalysis. (Although that's a subjective judgement call.) If post quantum security wasn't a concern, you could choose from ...


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You can take a look at Dan Berstein's Cureve2519. It's a non-NIST, non-NSA curve and he has his own adaptation of DSA that goes with it. However, I suppose it's possible to parallelize an attack on this, so it may not be resistant to quantum computing attacks. As for symmetric encryption, it's important to note that AES was developed by the international ...


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If you need security against quantum attacks, there aren't that many options. I would go for a lattice-based encryption like NTRU or something based on ring learning with errors. There are no "magic numbers" involved and the assumptions they are based on have been scrutinized by the academic community. NTRU has been around for a decade and has pretty good ...


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Layering your encryption mechanisms like that would not display collusion-resistance between the two schemes. For example, someone with an Org-A key could decrypt the outer encryption over a record designated for Org-A administrators and then pass the inner ciphertext to someone with an Administrator key. Of course, you could use a different key for each ...



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