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A lot of modern cryptography is based on some mathematical assumptions and aims to achieve what is called Computational Security. That means that the adversary (Eve) could get some information about the plaintext with a negligible probability and the adversary is modeled as someone with bounded computational power, storage and bounded time. So all the ...

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The reason Lamport's scheme is secure against a passive attacker is that even if they see $H^{n-1}(p)$ for a given $n$, the server would require the preimage of that hash, $H^{n-2}(p)$ on the next login. The active attack, in comparison, allows Trudy to find an earlier iteration than the server is expecting. That allows calculating several login hashes by ...

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in diffie-hellman key exchange algorithm vulnerability's is good defined by RSA lab : "The Diffie-Hellman key exchange is vulnerable to a man-in-the-middle attack. In this attack, an opponent Carol intercepts Alice's public value and sends her own public value to Bob. When Bob transmits his public value, Carol substitutes it with her own and sends it to ...

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TLSv1.1 doesn't have a different treatment of the key-exchange parameters than TLSv1.2 has. It's just a little less obvious. Let's dig into TLSv1.1 specification. On page 44 you'll find that ServerKeyExchange consists of ServerXXXParams params and Signature signed_params. Now on page 44 you'll actually find a definition of Signature. This definition signs ...

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Guess the catch in the video is in how the participants exchange details 'publicly'. If the Man-In-The-Middle can intercept and manipulate what is being 'publicly' shared, then the attempt to eavesdrop would still be successful.

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Saying that ECDH does not do authentication is not entirely accurate. If you use ECDH with static, known public keys and both sides prove knowledge of the shared secret, then you do get authentication. However, with ephemeral keys you need some way to authenticate the exchange of public keys. That could be ECDSA or it could be any other authentication. So ...

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