Cryptography Encrypting a file where multiple keys can decrypt the file?

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• Encrypting a file where multiple keys can decrypt the file?
• OTR version 4
• What is cryptographic bias?
• IoT Key-storage conundrum and Whitebox Crypto - Part 2
• PhD in Post-Quantum Cryptography
• What's the point of a codebook attack if you need to have the key to perform one?

Encrypting a file where multiple keys can decrypt the file? Posted: 25 Feb 2019 11:45 PM PST I'm looking to secure a series of files where a set of private keys, each individually, can decrypt the files. I need to introduce privacy in a three tier organogram where "local organisations -> country organisation -> HQ" where HQ can see everything, the countries only the files from the local organisations in that country and the local organisation only their files. Does something like this exist? If not, i can only think about putting all files three times encrypted on disk. submitted by /u/dm-86 [link] [comments]

OTR version 4 Posted: 25 Feb 2019 07:13 AM PST The specification: https://github.com/otrv4/otrv4/blob/master/otrv4.md submitted by /u/cherenkov_d [link] [comments]

What is cryptographic bias? Posted: 25 Feb 2019 11:17 AM PST I'm reading about differences between hash functions and the term "bias" is getting thrown around a lot. I googled but couldn't find much. One sentence I found from Wikipedia: The first is to construct linear equations relating plaintext, ciphertext and key bits that have a high bias; that is, whose probabilities of holding (over the space of all possible values of their variables) are as close as possible to 0 or 1. And on Stack Exchange: An OTP under cryptanalysis has a very strong bias (up to 30 % of symbols are represented by 5 out of 255 possible symbols) but no repetition could be found. Could anyone elaborate or explain a bit further? Thanks in advance. submitted by /u/Username8888 [link] [comments]

IoT Key-storage conundrum and Whitebox Crypto - Part 2 Posted: 25 Feb 2019 06:57 PM PST Part2 Continuing to explore the problem of '#crypto key storage' in #embedded environments. This post unlike the previous one is a bit hands on. You may find that observations + conclusions in this little walkthrough are rather interesting! link.medium.com/SVQYj4MExU #IoT #risks submitted by /u/npashi [link] [comments]

PhD in Post-Quantum Cryptography Posted: 25 Feb 2019 12:44 PM PST I am currently exploring the opportunity of undertaking a PhD in PQC. However, from what I have realised, unless you can come up with a completely new scheme in some way, it would seem bad to just take one of the existing ones and say "I would like to improve them" as a research proposal. What would some good general ideas be regarding starting a PhD in PQC? Do they have to do with creating a new schemes from scratch, optimising known algorithms, library speedups and bug-fixes, or just take a known algorithm and build a whole framework around it in a certain area (e.g. electronic signatures)? submitted by /u/gengiskhangr [link] [comments]

What's the point of a codebook attack if you need to have the key to perform one? Posted: 25 Feb 2019 07:57 AM PST I'm reading serious cryptography and in the book the Codebook Attack is explained for 16-bit block ciphers like so: Get the 65,536 (2{16}) ciphertexts corresponding to each 16-bit plaintext block. Build a lookup table—the codebook mapping each ciphertext block to its corresponding plaintext block. To decrypt an unknown ciphertext block, look up its corresponding plaintext block in the table If you can perform 1, that is encrypt each plaintext, then you already have the key. So this particular codebook you've just contructed only works for ciphers that used the key... that you already have. What am I misunderstanding here? submitted by /u/ImSupposedToBeCoding [link] [comments]

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