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Retaining the 3DES encryption key would probably do it. Now simply use the same IV as before and encrypt the file; the IV is only random when it is initially chosen. Alice could also encrypt the key and store it together with the message. You'd have to prove that you used the same key. That's no problem for larger messages in CBC mode where the possible ...


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Without the value of both A and B, I guess a conclusive decision might not be possible. But, I think I've got a probablistic method that determines (B>=A)==true when the gap B-A is large enough, and determines (B>=A)==false when B<A or A and B are so close that the algorithm cannot give correct answer with enough confidence. The method has 4 ...


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Assuming entities do want Bob to decrypt the sum, but not be able to decrypt individual ciphertexts: enitites would send commitments to plaintext to Bob while sending ciphertexts to Alice. Commitment scheme should be additively homomorphic such that Bob could open the result (over commitments collected) with plaintex decrypted as verification. This would ...


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Amendig the previous answer by fkraiem, let me focus on an example returning $1$. Schnorr verification equation could be rewritten: $$g^{r} h^{-c} a^{-1} = 1$$ for a group generator $g$, Prover response $r$, Verifier challenge $c$, initial message of Prover $a$ and public key $h$ such that $h = g^x$ for some private key $x$. With this protocol, Prover ...


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When you have eliminated the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes) If I find you in my dorm room and the door and windows are intact, I can only conclude that you somehow learned the entry code, because I do not know of any other way by which you could have entered my room without breaking the door or ...


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The answer to this question is not straightforward and has a lot to do with the "conference culture" of computer science. Unlike other fields, the main publication venues for CS are conferences and not journals. This isn't to say that journals don't have an important role; rather, you don't follow journals to see what research is being done - you follow ...


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Why do most of papers in the well-known conferences provide only the proof sketch? Space constraints, mostly (the paper has to fit in a certain number of pages). Often, the full proofs are given in the preprint version, available from the author's home page or the ePrint archive.



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