Mikero
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 2d revised Practical differences between circuits and turing machines for cryptography deleted 1 character in body 2d reviewed No Action Needed Deciphering and encrypting using Vigenére square for kids? 2d answered Practical differences between circuits and turing machines for cryptography Apr 25 answered Why only one secret value with Shamir's secret sharing? Apr 23 answered About ORAM initalization and running out of space Apr 15 comment Beavers Triple Vs BGW Multiplication on MPC The VSS constructions I know about (which are just the basic ones) have $O(n)$ overhead. What that means is that each party's VSS share is $O(n)$ size where $n$ is the total number of parties. In SPDZ for instance each party's share is constant-sized. Apr 14 comment Beavers Triple Vs BGW Multiplication on MPC You're right, it's 2 openings in the online phase -- I've updated accordingly. Apr 14 revised Beavers Triple Vs BGW Multiplication on MPC deleted 4 characters in body Apr 14 revised Beavers Triple Vs BGW Multiplication on MPC added 4 characters in body Apr 14 answered Beavers Triple Vs BGW Multiplication on MPC Feb 19 comment Terminology for secret sharing A scheme supporting this is a "threshold encryption scheme" -- i.e., an encryption scheme of the threshold variety -- or just "threshold encryption" for short. But since the threshold part only comes into play during decryption, it's fine to refer to that process as "threshold decryption" Feb 15 answered Can you update a (k,n) scheme to a (k+t, n+t) scheme (assuming old keys can be deleted)? Feb 6 comment How to prove that a function F isn't a pseudo random function Imagine someone making calls to $F'$ for many choices of $x$. If all the internal calls to $F$ are globally unique, then the outputs will look random. That's essentially the definition of $F$ being a PRF -- distinct inputs yield independently random outputs. In that case, $F'$ would be secure. If it is possible to choose some $x$'s to $F'$ that cause a repeated input to $F$, then you would notice duplicated blocks in the outputs. That's a very non-random thing to happen, so $F'$ would not be a PRF. Jan 22 comment Which cryptography technique does not increase the size of the plain data? You can get around the problem of CPA impossibility using deterministic nonce-based encryption, if there is some public but non-repeating value that you can use as a nonce (e.g., timestamp, hard disk block number) Jan 18 revised Could we share a secret key using the Birthday problem? added 83 characters in body Jan 18 answered Could we share a secret key using the Birthday problem? Dec 9 comment Santa Claus' secret permutation This is a special case of secure multi-party computation. Any general-purpose MPC protocol can do this, it only suffices to write the permutation-sampling process as a boolean/arithmetic circuit. Dec 4 reviewed Approve What type of encryption scheme can prevent cheating in this coin flip protocol? Dec 3 reviewed Approve Given $g,g^t$ in a cyclic group of order $pq$, is it hard to compute $g^{t^{-1}}$? Nov 30 reviewed Approve Signature schemes for underpowered devices (8bit microcontroller)