Cryptography How do I know if this crypto search engine is decentralized? |
- How do I know if this crypto search engine is decentralized?
- Monthly cryptography wishlist thread, March 2018
- Deep theories of Substitutions and Permutations?
| How do I know if this crypto search engine is decentralized? Posted: 10 Mar 2018 02:26 AM PST |
| Monthly cryptography wishlist thread, March 2018 Posted: 09 Mar 2018 04:06 AM PST This is another installment in a series of monthly recurring cryptography wishlist threads. The purpose is to let people freely discuss what future developments they like to see in fields related to cryptography, including things like algorithms, cryptanalysis, software and hardware implementations, usable UX, protocols and more. So start posting what you'd like to see below! [link] [comments]  |
| Deep theories of Substitutions and Permutations? Posted: 09 Mar 2018 03:53 AM PST Does there exist a deep mathematical theorem that goes something like this :
Whenever I find myself developing a new methodology for an encryption scheme, it usually takes a few weeks or a few months to realize my thinking is always going in the same direction. I always seem to re-arrive at the same sorts of mechanisms of Feistel block ciphers, wherein the F() function is some kind of bijective function. This cycle of thinking has happened to me so many times, that I am worried that I might be re-inventing the wheel on this topic. I get a strong intuitive feeling that I am just discovering a well-known theorem that all keyed, reversible ciphers can be expressed as a Substitution-Permutation network of some kind or another. I suspect that there might be a larger mathematical framework in which all ciphers dwell, but are all various manifestations of the theorem. Their only real "differences" are in attempts to make them faster in software, or better suit use in an electronic smartcard or a key fob , RFID, or whatever the target tech may be. These insights dawned on me in my attempts to form an encryption algorithm that operates on arbitrary block length sizes. In this we consider
Ciphertext c is plaintext p encrypted by E() with the key , k. You instead conjunct p with k and consider a bijective function F whose domain is p||k and whose range is c||k. So that we have function F() and the inverse of F as ~F()
More curt:
Now consider only range and domain elements whose length-in-bits is identical in all cases. In such an investigation, there are two things which jump out almost immediately.
In particular, the second item there is where you begin to really see this ghostly theorem manifest. I seemed to have found some deep mathematical connection between the length of the cipher's key and the size of the block that is being encrypted. These relationships always seem to hinge on permutations and the combinatorics of permutations. ( "What if the block length were 1024 bits, but the key was 8 bits. What concessions must an algorithm like that make? What if the block length were 8 bits, but the key was 512 bits?" etc. ) Over several months (of those early morning ponderings in the shower), you start entertaining ideas that all encryption algorithms are really just Substitution-Permutation networks masquerading under a different name. Your thoughts ? [link] [comments]  |
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