Jump to content

Rsync algorithm: Difference between revisions

From Wikipedia, the free encyclopedia
Content deleted Content added
describe the algo
m source and destination mixed up
Line 1: Line 1:
'''Rsync algorithm''' - an [[algorithm]] that [[rsync]] file transfer protocol and utility use.
'''Rsync algorithm''' - an [[algorithm]] that [[rsync]] file transfer protocol and utility use.


The source file is split into chunks, each of which is computed two checksums: a [[cryptographic hash]] and a rolling checksum. The rolling checksum has the property that if bytes ''n'' and ''n+k'' are known, the checksum of bytes ''n+1'' to ''n+k'' can be computed from the checksum of bytes ''n'' to ''n+k-1'' without knowing the intermediate bytes. The rolling checksum is computed for all chunk-sized contiguous blocks of the destination file; any that match a source chunk checksum are computed the cryptographic hash. All chunks of the source file which don't match anything in the destination are transferred, and the file is reassembled.
The destination file is split into chunks, each of which is computed two checksums: a [[cryptographic hash]] and a rolling checksum. The rolling checksum has the property that if bytes ''n'' and ''n+k'' are known, the checksum of bytes ''n+1'' to ''n+k'' can be computed from the checksum of bytes ''n'' to ''n+k-1'' without knowing the intermediate bytes. The rolling checksum is computed for all chunk-sized contiguous blocks of the source file; any that match a destination chunk checksum are computed the cryptographic hash. All parts of the source file which don't match any chunk in the destination are transferred, and the file is reassembled.


See also:
See also:

Revision as of 12:45, 12 November 2002

Rsync algorithm - an algorithm that rsync file transfer protocol and utility use.

The destination file is split into chunks, each of which is computed two checksums: a cryptographic hash and a rolling checksum. The rolling checksum has the property that if bytes n and n+k are known, the checksum of bytes n+1 to n+k can be computed from the checksum of bytes n to n+k-1 without knowing the intermediate bytes. The rolling checksum is computed for all chunk-sized contiguous blocks of the source file; any that match a destination chunk checksum are computed the cryptographic hash. All parts of the source file which don't match any chunk in the destination are transferred, and the file is reassembled.

See also: