Cryptography Protecting symmetric encryption against a post quantum world |
| Protecting symmetric encryption against a post quantum world Posted: 14 May 2019 02:23 AM PDT There has been a lot of recent talk about whether AES256 will be secure in a world where sufficiently large quantum computers (QC) exist. Some pundits put this at 10-15 years time. From other experience I have I think this is the time when QC becomes commercially available, but it will (has?) be the case that certain three letter agencies will have sufficiently power full QC's in their basement before then. I want to explore the risks of an efficient implementation of Grover's Algorithm. If we assume that today a classical computer system can process 1 billion attempts per second. Lets ramp that up to 100 billion just to think outside the box. At this rate, I calculate that a full key space space would take 2E58 years - or longer than the age of the universe to date. It could be a lot shorter, because the key could be guessed early in the process, so if we say, on average, the key is guessed in the first half of the scan, then the time taken is still approaching infinity for all practical purposes. If Grover's Algorithm can deliver the same rate of key cracking (that's a big IF), and we all accept that Grover's algorithm uses SQRT(N) time, where N is the keysize, then this is equivalent to cracking a 128 bit key today. That would take 1E20 years. Am I wrong in thinking that, without a major breakthrough in technology above and beyond QC, data encrypted with AES256 will remain secure for the future? [link] [comments]  |
| How is it( encryption ) implemented Posted: 13 May 2019 08:25 AM PDT Hey guys, I'm still relatively new to this sub reddit and new to crypto, I have been programming for about 2 - 3 years and currently doing a course in computer science although we don't cover crypto in detail we did have a module that glances through the ideas of crypto such as perfect secrecy, the consistency equation the one time pad, etc, I have a brief understanding and know how certain ciphers such as the Viginere,caesar cipher, the one time pad work, I also know how a two time or many time pad attack happens, I have some knowledge on PRG's. but my question is how is encryption implemented? let me use WEP and WPA as my example as these are the two main protocols I'm interested in, how are they implemented? It's quite hard to explain but how does the process of one machine( AP) sending the station encrypted packets work? how is it programmed? I know of algorithms such as AES,DES,triple DES, RC4 but how does the OS actually know what protocols WEP and WPA are and how is the encryption built into the OS? and also how do programmers build such protocols and encryptions like WEP and WPA? sorry if this is poorly explained, I'm not looking for someone to explain the whole process but if someone could even point me in the right direction I would be more than grateful . thanks [link] [comments]  |
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