* < tt > sum </ tt >, a Unix command ( also ported to Win32 ) that generates order-independent sums ; uses two different algorithms for calculating, the SYSV checksum algorithm and the BSD checksum ( default ) algorithm.

* List of checksum algorithms

This schema is also used in many text checksum and fingerprint algorithms.

One can adapt certain checksum or fingerprinting algorithms for use as hash functions.

It is important to understand the cryptographic signatures are much more than an error checking technique akin to checksum algorithms, or even high reliability error detection and correction algorithms such as Reed-Solomon.

As with simpler checksum algorithms, the Fletcher checksum involves dividing the binary data word to be protected from errors into short " blocks " of bits and computing the modular sum of those blocks.

Digit sums are also a common ingredient in checksum algorithms and were used in this way to check the arithmetic operations of early computers.

In particular, the popular CRC32 checksum provides only 16 bits ( the higher half of the result ) that are usable for hashing.

The third and fourth bytes are a checksum of the entire ICMP message.

Starting with SCSI-U160 ( part of SCSI-3 ) all commands and data are error checked by a CRC32 checksum.

* Forensic imaging or acquisition is the process where the entire drive contents are imaged to a file and checksum values are calculated to verify the integrity ( in court cases ) of the image file ( often referred to as a " hash value ").

The JAR itself is not signed, but instead every file inside the archive is listed along with its checksum ; it is these checksums that are signed.

These parity files are used to perform checksum verification, and can also repair corrupted or missing data.

The delimiter between the filename and checksum is always one or several spaces ; tabs are never used.

While CSA algorithm uses 64-bit keys, most of the time only 48 bits of key are unknown, since bytes 3 and 7 are used as checksum bytes in CA systems, and may be easily recalculated.

In our example, there are only 255 possible checksum values, so it is easy to see that even random data has about a 0. 4 % probability of having the same checksum as our message.

At the end of the data word, the modulus operator is applied and the two values are combined to form the Fletcher checksum value.

When the data word is divided into 8 bit blocks, as in the example above, two 8-bit sums result and are combined into a 16-bit Fletcher checksum.

When the data word is divided into 16 bit blocks, two 16-bit sums result and are combined into a 32-bit Fletcher checksum.

When the data word is divided into 32 bit blocks, two 32-bit sums result and are combined into a 64-bit Fletcher checksum.

The length and checksum are calculated over the second and third field only, so that the actual total length of the packet is three more than the length as reported in the first two bytes of the packet.

The ABN is an eleven digit number where the first two digits are a checksum.

The cksum command reads each file given in its arguments, or standard input if no arguments are provided, and outputs the file's CRC checksum and byte count.

TCP checksum offload and large segment offload are supported by the majority of today's Ethernet NICs.

Errors are normally detected by the hardware, either by the disk drive by checking the data read from the disk using the ECC / CRC error correcting code stored alongside the data on disk, or in the case of a RAID array by comparing the contents of the RAID strips with the ECC checksum or parity of the RAID stripe.

160 bits of the key are checksum material.

* Data corruption problems have led to most programs using segmented downloading using some sort of checksum or hash algorithm to ensure file integrity ( to receive file intact ) and uniqueness ( to not receive bits of other similar files ).

* Cyclic redundancy check, a type of hash function used to produce a checksum in order to detect errors in data storage or transmission

* Message Integrity Code, a cryptographic checksum used in wireless communications

The rolling checksum used in rsync is based on Mark Adler's adler-32 checksum, which is used in zlib, and is itself based on Fletcher's checksum.

For those used to packet communications systems where each packet has a checksum, note that there is no checksum used in the message format.

A " rolling checksum " version of Adler-32 is used in the rsync utility.

For example, a CRC was used for message integrity in the WEP encryption standard, but an attack was readily discovered which exploited the linearity of the checksum.

A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum.

UUHash will hash the first 300 kilobytes using MD5 and then apply a smallhash function ( identical to the CRC32 checksum used by PNG ) to 300 KB blocks at file offsets 2 < sup > n </ sup > MB with n being an integer incremented from 0 until the offset reaches end of file.

is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers in US and Canadian Social Insurance Numbers.

The following formula can be used to generate the 9th digit in the checksum:

One common method used to prevent cheating is for a checksum ( such as an MD5 sum ) to be calculated against each game datafile on the client computer, and for these checksums to be reported to the server before the client can join the game.

In addition, in practice packets would probably have to be retransmitted occasionally when real checksum errors and network problems occur.

Therefore, IPv6 routers do not need to recompute a checksum when header fields ( such as the time to live ( TTL ) or hop count ) change.

Each of these smaller problems is then encoded as a relation between a checksum and a packet such that whether the checksum is accurate or not is also the answer to that smaller problem.

Interestingly, the PDP-1 has a hardware built-in loader, such that an operator need only push the " load " switch to instruct the paper tape reader to load a program directly into core memory ; the boot loader reads into core memory either the second-stage boot loader ( called Binary Loader of paper tape with checksum ) or the operating system from an outside storage medium such as a paper tape, a punched card, or a disk drive.

Packages also contain metadata, such as the software's name, description of its purpose, version number, vendor, checksum, and a list of dependencies necessary for the software to run properly.

By means of an error detection code, such as a checksum, the transport protocol may check that the data is not corrupted, and verify correct receipt by sending an ACK or NACK message to the sender.

Common methods for verifying that operating system patches have not been altered include the use of cryptographic hash, such as an MD5 based checksum, or the use of read-only media.

An example safeguard is to keep a backup of the firmware to use in case the primary copy is determined to be corrupt ( usually through the use of a checksum, such as a CRC ).

An additional advantage of yEnc over previous encoding methods, such as uuencode and Base64, is the inclusion of a CRC checksum to verify that the decoded file has been delivered intact.

Because of this, manufacturers of HIDS usually construct the object-database in such a way that makes frequent updates to the checksum database unnecessary.

slapt-get builds functionality on top of the native Slackware package tools ( installpkg, upgradepkg and removepkg ) enabling package query, remote fetching, system updates, integrated changelog information, and many optional advanced features such as dependency resolution, package conflicts, suggestions, checksum and public key verification, and transfer resumption.

When hex dumps are intended to be manually entered into a computer, such as was the case with print magazine articles of home computer era a checksum byte ( or two ) would be added at the end of each row, commonly calculated as simple 256 modulo of sum of all values in the row or a more sophisticated CRC.

It does, however, change the checksum of the executable, so it is not something that can be done with signed programs, or programs that are managed by a configuration management tool that uses checksums ( such as MD5 checksums ) to manage file versions.