Hashing in SHA512 using a salt? - Python

Question

I have been looking through ths hashlib documentation but haven't found anything talking about using salt when hashing data.

Help would be great.

Answer 1

Samir's answer is correct but somewhat cryptic. Basically, the salt is just a randomly derived bit of data that you prefix or postfix your data with to dramatically increase the complexity of a dictionary attack on your hashed value. So given a salt s and data d you'd just do the following to generate a salted hash of the data:

import hashlib hashlib.sha512( s + d ).hexdigest() 

See this wikipedia article for more details

Answer 2

Just add the salt to your sensitive data:

>>> import hashlib >>> m = hashlib.sha512() >>> m.update('salt') >>> m.update('sensitive data') >>> m.hexdigest() '70197a4d3a5cd29b62d4239007b1c5c3c0009d42d190308fd855fc459b107f40a03bd427cb6d87de18911f21ae9fdfc24dadb0163741559719669c7668d7d587' >>> n = hashlib.sha512() >>> n.update('%ssensitive data' % 'salt') >>> n.hexdigest() '70197a4d3a5cd29b62d4239007b1c5c3c0009d42d190308fd855fc459b107f40a03bd427cb6d87de18911f21ae9fdfc24dadb0163741559719669c7668d7d587' >>> hashlib.sha512('salt' + 'sensitive data').hexdigest() '70197a4d3a5cd29b62d4239007b1c5c3c0009d42d190308fd855fc459b107f40a03bd427cb6d87de18911f21ae9fdfc24dadb0163741559719669c7668d7d587'