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What is special about a 20byte (160bit) key?

开发者 https://www.devze.com 2023-01-11 20:27 出处：网络

I was emailed a reset key. It was 40 hex letters, so 20 bytes which is 160 bits. I thought to myself, why 160 bits? Maybe it\'s a 128 (key) + 32 bit (checksum or id or something). Maybe something else

相关专题：key security

I was emailed a reset key. It was 40 hex letters, so 20 bytes which is 160 bits. I thought to myself, why 160 bits? Maybe it's a 128 (key) + 32 bit (checksum or id or something). Maybe something else. I am sure it was done for a reason but why? (PS: The person on the other end seems to not want to say why or maybe doesn't know. So asking elsewhere hasn't worked. I felt silly.)

I am sure script is written in PHP as the rest of the site is.

ha, ok, so it might be开发者_StackOverflow a SHA-1. But what would be hashed? I reset my password twice this evening, i am not sure how long apart but they were the same keys. I'll try tomorrow. Maybe its a datestamp + user id i wonder...

It could be a SHA-1 hash, which has 160 bit.

160 bits is the size of a SHA-1 hash.

RFC 3174 http://www.faqs.org/rfcs/rfc3174.html

(aka SHA-1)