X-Nico

9 unusual facts about hash function


BitComet

Since version 0.86 BitComet includes discussion and stat-tracking features which send information about torrents to the Bitcomet.com servers, including the torrent hash.

EMule

Each file that is shared using eMule is hashed as a hash list comprising separate 9500 kibibyte chunks using the MD4 algorithm.

Hash function

Donald Knuth notes that Hans Peter Luhn of IBM appears to have been the first to use the concept, in a memo dated January 1953, and that Robert Morris used the term in a survey paper in CACM which elevated the term from technical jargon to formal terminology.

The same technique can be used to map two-letter country codes like "us" or "za" to country names (262=676 table entries), 5-digit zip codes like 13083 to city names (100000 entries), etc.

PeerWeb

The site itself does not host the files, but collects and sorts special Magnet links, which contain a hash value to identify files being shared by other Gnutella2 users through clients such as Shareaza.

Product activation

In one form, product activation refers to a method invented by Ric Richardson and patented (US 5,490,216) by Uniloc where a software application hashes hardware serial numbers and an ID number specific to the product's license (a product key) to generate a unique installation ID.

Tamper-evident

The document, email, or file to be protected is used to generate a signed hash, a number generated from the contents of the document.

Theraography

Examples of hard fingerprints are hashcode (or Hash function), for which even a one bit modification of the original content produces different fingerprint and exclude all recognition process.

WinMX

If a file was found, the hash of the file along with IP address and Primary node details of the user with the file was sent to the user who made the search.


CyaSSL

CTaoCrypt Provides RSA, DSS, Diffie–Hellman, EDH, NTRU, DES, Triple DES, AES (CBC, CTR, CCM, GCM), Camellia, ARC4, HC-128, MD2, MD4, MD5, SHA-1, SHA-2, BLAKE2, RIPEMD-160, Random Number Generation, Large Integer support, and base 16/64 encoding/decoding.

Feistel cipher

For example, MISTY1 is a Feistel cipher using a three-round Feistel network in its round function, Skipjack is a modified Feistel cipher using a Feistel network in its G permutation, and Threefish (part of Skein) is a non-Feistel block cipher that uses a Feistel-like MIX function.

Hans Peter Luhn

These techniques included full-text processing; hash codes; Key Word in Context indexing (see also Herbert Marvin Ohlman); auto-indexing; automatic abstracting and the concept of selective dissemination of information (SDI).

Myspace IM

Logging in involves a challenge/response protocol using the SHA-1 hash function and RC4.


see also

Feature hashing

When a second hash function ξ is used to determine the sign of a feature's value, the expected mean of each column in the output array becomes zero because ξ causes some collisions to cancel out.

FNV

Fowler–Noll–Vo hash function, a non-cryptographic hash function created by Glenn Fowler, Landon Curt Noll, and Phong Vo

Microsoft Excel

The situation changed fundamentally in Excel 2007, where the modern AES algorithm with a key of 128 bits started being used for decryption, and a 50,000-fold use of the hash function SHA1 reduced the speed of brute-force attacks down to hundreds of passwords per second.