Looking for more information on X11, X13, and SHA3 algos

[cookiemonster7]

I would like to study various different algorithms from a cryptographical and mathematical perspective, I have looked all over for raw data on various alternative algos and cant seem to find anything.

[darkota]

x11 is the best

x13 is a copy of x11 with nothing added.

sha3 is like sha256, and can be mined/destroyed by ASIC's.

[cookiemonster7]

I would like to thoroughly understand the algorithms for a university research project to discuss the development of crypto currencies, I can find some info on keccak, but not much on X11 or X13.

[gjhiggins]

I would like to thoroughly understand the algorithms for a university research project to discuss the development of crypto currencies, I can find some info on keccak, but not much on X11 or X13.

There's a list of algorithms for CPU mining which has some info about x11 (but read on).

You'll definitely want to visit the SHA3 Zoo maintained by the IAIK Krypto group of Graz University of Technology. The crypto group there maintains a complete record of the official NIST communications for each candidate hash function along with the zipped file of sphlib-compatible C reference implementation and full documentation, right down to the hardware details.

I'd guess that neither x11 nor x13 would be recognised as algorithms as such by your typical crypto worker/researcher, although strictly speaking it's not a wildly incorrect description. To use a musical analogy, they are more akin to arrangements than compositions.

The terms "x11" and "x13" in this context refer to the programmatic chaining of the sequential application of a fixed set of hash functions, 11 in total in the case of x11 (BLAKE, Blue Midnight Wish, Grøstl, JH, SHA3, Skein, Luffa, CubeHash, SHAvite-3, SIMD, ECHO) and unsurprisingly, 13 in the case of x13 - as x11 with the addition of Fugue and Hamsi (the latter is a very questionable inclusion, given the information available at the SHA3 Zoo).

As is sadly typical in the altcoin tech cesspit, the respective spec for x11 and x13 is the implementation itself, you need to consult the C++ source code itself. It's not difficult to read, given the highly restricted domain of discourse.

x11 - Wavecoin

x13 - Peercoin

c11 - Chaincoin

As a grace note: Chaincoin was released at pretty much the same time as Darkcoin, Chaincoin's "c11" chains the same 11 hash function as x11 but in a slightly different order and it could be mischievously claimed as the only 11-chain-algo altcoin that hasn't been PnD'd

My current count is 111 altcoins using X11 for proof of work,  22 altcoins using (the up-and-coming) x13 and just the single instance of c11.

HTH

Cheers,

Graham