裁剪的哈希是否更难破裂？

Question

Cropping a hash should mean losing some of the data it represents so I was wondering if cropped hashes are harder to crack and more specifically if storing cropped password hashes for user authentication is an idea worth examining.

Answer 1

Take this idea to its extreme: assume you're storing only the first hex character of your hashed passwords.

All your users' passwords would hash into one of sixteen values:

0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F

I'll admit that it would be very difficult for John The Ripper to brute-force decode these passwords, but it would also let someone guess another user's password in about eight tries on average.

Ooops.

If anything, you should store longer hashes. Salt well instead.