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(storage, communications)
A computed value which depends on the contents of a block of data and which is transmitted or stored along with the data in order to detect corruption of the data. The receiving system recomputes the checksum based upon the received data and compares this value with the one sent with the data. If the two values are the same, the receiver has some confidence that the data was received correctly.

The checksum may be 8 bits (modulo 256 sum), 16, 32, or some other size. It is computed by summing the bytes or words of the data block ignoring overflow. The checksum may be negated so that the total of the data words plus the checksum is zero.

Internet packets use a 32-bit checksum.

See also digital signature, cyclic redundancy check.


A value used to ensure data are stored or transmitted without error. It is created by calculating the binary values in a block of data using some algorithm and storing the results with the data. When the data are retrieved from memory or received at the other end of a network, a new checksum is computed and matched against the existing checksum. A non-match indicates an error.

Just as a check digit tests the accuracy of a single number, a checksum tests a block of data. Checksums detect single bit errors and some multiple bit errors, but are not as effective as the CRC method. Checksums are also used by the Sophos antivirus software to determine if a file has changed since the last time it was scanned for a virus. See ECC memory and Sophos.
References in periodicals archive ?
Using Library of Congress' Bagger tool, the three tiers are "bagged" into a folder, and checksums are run on all three files.
The calculated CRC16 checksum and the received one are compared.
Checksum 3--Generate nine keys, encrypt all the digits (but the final) with one of these keys, and replace the checksum digits with the checksum plus a key identifying value from 1 to 9.
DSpace stores a checksum for each digital file it manages, and the system should constantly monitor its asset store for file corruption or other problems.
If any bit in the message is altered during transmission, the checksum would be different.
EMusic's search bot uses "acoustic fingerprinting" technology that tracks the MD5 checksum created by the Napster client to uniquely identify songs.
note: the checksum of 101 and the checksum of 110 are both 2.
If the checksum in a message doesn't match the number being sent, the display will alert the operator.
First, a good cryptographic checksum ensures that small changes to the data result in large and seemingly random changes to the checksum.
Also added is support for XLINK checksum units larger than 8 bits.
They are run by amateur hackers who graduated from taking down websites to recruiting new members for terrorist groups like Islamic State (IS), according to Bahrain-based Checksum Consultancy principal consultant Muhammed Haroon.
The major development in this release is the support to apply checksum validation on Codabar coded barcode.