hashes: truncate -> reduce, mention SHA-256

the longer SHA-256 hashes are not truncated, but in fact processed.

Co-authored-by: Thomas <twatson52@mac.com>
This commit is contained in:
Valentin Gagarin 2022-07-13 11:42:16 +01:00
parent 9cabba1fc3
commit 29c062537d

View file

@ -62,12 +62,13 @@ Store objects are therefore said to be either [input-addressed](#input-addressin
::: {.note} ::: {.note}
**Historical note**: The 20 byte restriction is because originally digests were [SHA-1][sha-1] hashes. **Historical note**: The 20 byte restriction is because originally digests were [SHA-1][sha-1] hashes.
This is no longer true, but longer hashes and other information are still truncated to 20 bytes for compatibility. Nix now uses [SHA-256][sha-256], and longer hashes are still reduced to 20 bytes for compatibility.
::: :::
[digest]: https://en.m.wiktionary.org/wiki/digest#Noun [digest]: https://en.m.wiktionary.org/wiki/digest#Noun
[hash]: https://en.m.wikipedia.org/wiki/Cryptographic_hash_function [hash]: https://en.m.wikipedia.org/wiki/Cryptographic_hash_function
[sha-1]: https://en.m.wikipedia.org/wiki/SHA-1 [sha-1]: https://en.m.wikipedia.org/wiki/SHA-1
[sha-256]: https://en.m.wikipedia.org/wiki/SHA-256
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