ADLER checksum

Use this tool to quickly calculate ADLER checksums.

Use this tool to quickly calculate ADLER checksums.

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ADLER checksums

In 1995, Mark Adler created Adler-32, a checksum algorithm derived from Fletcher's checksum with modifications. While sacrificing some reliability for increased speed compared to a cyclic redundancy check of the same length, Adler-32 remains more reliable than Fletcher-16 and slightly less reliable than Fletcher-32.

Adler-32 holds significance as it is incorporated into the widely utilized zlib compression library, which was also developed by Mark Adler. Additionally, a variant of Adler-32 known as a "rolling checksum" is employed in the rsync utility.

Similar to the standard CRC-32, Adler-32 checksums are susceptible to forgery, making them unsuitable for safeguarding against intentional tampering. However, Adler-32 generally exhibits faster performance than CRC-32 across many platforms. Nonetheless, Adler-32 does possess a vulnerability for short messages comprising only a few hundred bytes, as the resulting checksums may inadequately cover the available 32 bits.