Name hashing improvements

[richfitz]

see https://github.com/imperialebola2018/names/blob/50f775abc2fe88da9109f5f1518f7942aa2fe40f/functions.R#L65-L83

• don't use digest for cryptographic purposes
• consider using a slow hash function to make table attacks infeasable (this is really quite slow though!)
• allow salt to be saved between sessions without being recorded in the script

there is also (incomplete) work allowing

• substitutions to be used to patch names - a more flexible version of the name scrubbing
• comparing the hashed and clear names so that the person doing the hashing can see what has been missed

[thibautjombart]

Thanks for this. Any hope you could PR these changes before the end of July by any chance? ;)

[dirkschumacher]

Ah, just posted a similiar issue without seeing this here #6 🙈

@richfitz what lib would you suggest. libsodium?

I am happy to work on a PR

[dirkschumacher]

sodium has hmac hashing build it.

[dirkschumacher]

@richfitz Thibaut merged my PR. Do you have any other suggestions? The PR does not cover the full list of suggested features, but it uses scrypt and maintains the same interface as before.