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Published: 16/06/2018This is the generalized version of the previous edition of the question. Let $F(x) = \text{Keccak}f[1600](x)$. We can define the following notation: $$\begin{array}{l} {F^0(x)} = x,\\ {F^1(x)} = F(x) ... Read moreSource: crypto.stackexchange.com


Published: 16/06/2018Many group signature schemes follow signencrypt then prove paradigm, where a membership certificate, is encrypted using some publickey encryption scheme. There are some encryption free group signatu ... Read moreSource: crypto.stackexchange.com

Published: 16/06/2018I am implementing the key exchange scheme proposed by zhang et al. on Sage. In the implementation of the scheme, they have used the two distributions $\chi_{\alpha}, \chi_{\beta}$. How to choose $\alp ... Read moreSource: crypto.stackexchange.com

Published: 16/06/2018I have started learning authentication protocols with basic PAP first, even though it does not provide strong identity check. To understand it paractically i want to refer some PAP implementation code ... Read moreSource: crypto.stackexchange.com

Published: 16/06/2018If I have to argue that an assumption A is stronger than B, should I argue this way: An adversary breaking the security of A does not translate to breaking the security of B. But, if an adversary bre ... Read moreSource: crypto.stackexchange.com

Published: 16/06/2018I wanted to know how much one Ethereum KECCAK256(hash) is in FLOPS. I know bitcoin is 12,697 flops per hash. Read moreSource: crypto.stackexchange.com

Published: 15/06/2018Lets assume that there is a decentralized network $N$ with participants $A,B,C, D$ and that there was a message $m$ that all of $A,B,C,D$ agreed to. An outsider $X$ wants to know via signatures that $ ... Read moreSource: crypto.stackexchange.com

Published: 15/06/2018I'm a total noob here, so please go easy on me if this is the wrong place to post this. I have a software program running on a piece of hardware, the software generates a 4 digit numeric pin, then you ... Read moreSource: crypto.stackexchange.com

Published: 15/06/2018I am trying to design a scheme that would allow the following: Alice has a number $a$ which she wants to keep secret Bob has a number $b$ which he wants to keep secret Alice can "transfer" a number to ... Read moreSource: crypto.stackexchange.com

Published: 15/06/2018I've come to use AES/SIC for my purpose as I want to write an encrypted file and read it back with the possibility to seek (I only need to read parts of it and don't want to decrypt the whole file jus ... Read moreSource: crypto.stackexchange.com

Published: 15/06/2018I hate asking for a reference, but I'm having a hard time finding this. The iana page on tls extensions just links me back to rfc5246 where it only has the following values: enum { none(0), md5(1), sh ... Read moreSource: crypto.stackexchange.com

Published: 15/06/2018Universally composable protocols provide security even in highly complex environments like the Internet. Without setup assumptions, however, UCsecure realizations of cryptographic tasks are impossibl ... Read moreSource: eprint.iacr.org

Published: 15/06/2018Timelock encryption is a method to encrypt a message such that it can only be decrypted after a certain deadline has passed. We propose a novel timelock encryption scheme, whose main advantage over ... Read moreSource: eprint.iacr.org

Published: 15/06/2018We initiate a study of the security of cryptographic primitives in the presence of efficient tampering attacks to the randomness of honest parties. More precisely, we consider ptampering attackers th ... Read moreSource: eprint.iacr.org

Published: 15/06/2018Let's say Alice has file $F$ and she generates key $K$. She widely publishes the $hash(F)$ for identification. She wants to sell the file to Bob. She encrypts the file with $K$ and sends both $E_f = E ... Read moreSource: crypto.stackexchange.com

Published: 14/06/2018I'm trying to find an authoritative source for the HMAC Key sizes for each of the hashing algorithms below. Specifically for TLS implementations of HMAC. I found this table in RFC5246 : MAC Algorithm ... Read moreSource: crypto.stackexchange.com

Published: 14/06/2018I want to know what the state of the art in the following cryptographic problem is. Assume a public channel on which encrypted messages are exchanged, using symmetric key encryption. I hold a couple o ... Read moreSource: crypto.stackexchange.com

Published: 14/06/2018This question already has an answer here: Should we MACthenencrypt or encryptthenMAC? 12 answers I am using HMAC to create a message authentication code. My question is, does it matter if I use ci ... Read moreSource: crypto.stackexchange.com

Published: 14/06/2018I am pretty new to ASN.1 format. I have a PKCS#7 signature which after doing an ASNdump looks like the one below. Can someone help me understand what each element below signifies? I could only identif ... Read moreSource: crypto.stackexchange.com

Published: 14/06/2018Let $F(x) = \text{Keccak}f[1600](x)$. Consider the following function: $$G(x) = F(x) \oplus F(F(x)).$$ Can we assume that the number of outputs of $G(x)$ is approximately equal to $(11/e) \times 2^{ ... Read moreSource: crypto.stackexchange.com

Published: 14/06/2018In a functional encryption scheme, secret keys are associated with functions and ciphertexts are associated with messages. Given a secret key for a function f, and a ciphertext for a message x, a decr ... Read moreSource: eprint.iacr.org