# Questions tagged [checksum]

A checksum is a small chunk of data calculated from another larger piece of data, used to detect any transmission errors in the data. Use this tag for questions related to calculating or verifying checksums. (See also hashing)

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### Generate Parity bits

Given a binary message, and the number of parity bits, generate the associated parity bits. A parity bit is a simple form of error detection. It's generated by counting the number of ...
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### Encode the systematic binary Varshamov–Tenengolts code

Background Here on CGCC, a commonly seen subgenre is radiation-hardening – writing a program that works even if one character is deleted. A similar problem is studied in the field of coding theory: ...
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### Compute the Redwolf Checksum™ of some data

I will preface this by saying that I made this for fun; I have absolutely no formal knowledge on cryptography or error correction. Do not use this algorithm in anything remotely important. I was kind ...
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### For what block sizes is this checksum valid?

The input: As an example, take a list containing a number of bits (in this case, 32): 11000010000100111011000011001011 We can calculate a simple checksum of this ...
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### Converting ISBN-13 to ISBN-10

Introduction In this challenge your task is to generate the ISBN-10 code for books given its ISBN-13 code, assuming that such a code exists. Such an ISBN-13 code consists of several parts separated ...
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### Is my barcode valid?

An EAN-8 barcode includes 7 digits of information and an 8th checksum digit. The checksum is calculated by multiplying the digits by 3 and 1 alternately, adding the results, and subtracting from the ...
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### Compute the Adler-32 checksum

Background Adler-32 is a 32-bit checksum invented by Mark Adler in 1995 which is part of the widely used zlib library (also developed by Adler). Adler-32 is not as reliable as a 32-bit cyclic ...
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### Generate a parity bit

A parity bit, is one of the simplest forms of a checksum. First, you have to pick the parity, even or odd. Let's say we pick even. Now, we need a message to transmit. Let's say our message is "...
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