Not true. Password hashing algorithms should be resource intensive enough to prevent brute force calculation from being a viable route. This is why bcrypt stores a salt, a hash, and the current number of rounds. That number of rounds should increase as CPUs get faster to prevent older hashes from existing in the wild which can be more effectively broken by newer CPUs.
I was incorrect about the goal being minimal resources. I should have written that that goal was to have controlled resource usage. The salt does not increase the expense of the the hash function. Key stretching techniques like adding rounds increase the expense to reach the final hash output but does not increase the expense of the hash function. High password length allowances of several thousand characters should not lead to a denial of service attack but they don’t materially increase security after a certain length either.
Edited to remove untrue information. Thanks for the corrections everyone.
Not true. Password hashing algorithms should be resource intensive enough to prevent brute force calculation from being a viable route. This is why bcrypt stores a salt, a hash, and the current number of rounds. That number of rounds should increase as CPUs get faster to prevent older hashes from existing in the wild which can be more effectively broken by newer CPUs.
I was incorrect about the goal being minimal resources. I should have written that that goal was to have controlled resource usage. The salt does not increase the expense of the the hash function. Key stretching techniques like adding rounds increase the expense to reach the final hash output but does not increase the expense of the hash function. High password length allowances of several thousand characters should not lead to a denial of service attack but they don’t materially increase security after a certain length either.
Hashes are one way functions. You can’t get from hash back to input
True. I was all kinds of incorrect in my hasty typing. I’ll update it to be less wrong.