How to securely encrypt a file with an insecure password in Rust

Re:How to securely encrypt a file with an insecure password ... by charcircuit on Wednesday January 19, 2022 @03:28PM (#29999541)

How does a KDF add entropy to a passphrase?

I would expect the entropy to remain the same.

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Re:How to securely encrypt a file with an insecure password ... by admax88qqq on Wednesday January 19, 2022 @04:40PM (#30000586)

It doesn't, this article is inaccurate

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Re:How to securely encrypt a file with an insecure password ... by staticassertion on Wednesday January 19, 2022 @03:55PM (#29999995)

It adds a salt. Otherwise entropy shouldn't really be a factor - your input password could be more entropic than your output hash, in terms of shannon entropy/ number of bits needed to represent the values.

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Re:How to securely encrypt a file with an insecure password ... by charcircuit on Wednesday January 19, 2022 @04:26PM (#30000388)

I am referring to the diagram saying low entropy passphase -> high entropy key

Since the salt is included in the output of the KDF, is it really adding entropy to the key?

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Re:How to securely encrypt a file with an insecure password ... by staticassertion on Wednesday January 19, 2022 @05:21PM (#30001188)

Yeah, I found the diagram a bit confusing as well. I don't think that a KDF is adding any entropy.

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Re:How to securely encrypt a file with an insecure password ... by tptacek on Wednesday January 19, 2022 @06:13PM (#30001846)

The salt adds no entropy.

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