Ed2k URI scheme: Difference between revisions

Revision as of 00:08, 2 December 2010

Revision as of 19:17, 12 January 2011

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== eD2k hash algorithm ==

The eD2k hash function is an [[MD4]]hash list|root hash]] of ana list of [[MD4]] [[hash listfunction|hashes]], and gives a '''different''' result than simply MD4:

The file data is divided into full ''chunks'' of 9728000 bytes plus a remainder chunk, and a separate '''128-bit MD4 checksum''' is computed for each. If the file length is an exact multiple of 9500 KiB, the remainder zero size chunk is still used at the end of the hash list. The eD2k hash is computed by concatenating the chunks' MD4 checksums in order and hashing the result using MD4. Although, if the file is composed of a single non-full chunk, its MD4 hash is used with no further modifications.<ref>emule source, method <code>CKnownFile::CreateFromFile</code>.</ref>