Use cryptographically generated passwords

[sebastienros]

Seeing an attempt to generate random passwords and other discussions about the recommended approach I am providing what I think is a better approach.

This could also be used to generate random ids but it's not part of this PR.

Microsoft Reviewers: Open in CodeFlow

[eerhardt]

Looks fine to me. Would be good to get @mitchdenny to review.

[mitchdenny]

This is not length, this is the # of lower case chars.

[mitchdenny]

Oh I see what you are demonstrating. :)

[mitchdenny]

UPDATE: Ignore this comment - but leaving for transparency :)

It is definitely better than what we have today :)

One thing that I thought of and I don't know if it is really a practical issue for us given the ephemeral nature of the passwords we are generating, is that this code would always seem to be in the form:

[lower case chars set][upper case chars set][digit chars set][special chars set]

This reduces the possible set of characters for each individual character position which reduces the possible combination of passwords. To give a concrete example, here is the dictionary of characters we have by category:

Set	Characters	Quantity
Lowercase	abcdefghjkmnpqrstuvwxyz	23
Uppercase	ABCDEFGHJKMNPQRSTUVWXYZ	23
Digits	0123456789	10
Special chars	-_#@!./:[]{}+*()~	17

So, if we call the following code (like we do in SQL Server):

GeneratePassword(6, 6, 2, 2)

The number of combinations is:

23 * 23 * 23 * 23 * 23 * 23 * 23 * 23 * 23 * 23 * 23 * 23 * 10 * 10 * 17 * 17 = 6.33332646085387E+20

Compare this with a GUID which is 1.208925819614629174706176e+24

If we instead allowed the characters to be in any position and the options on the password meant the minimum number of characters of a given set and didn't correlate to password length or where they were found.

[eerhardt]

If we instead allowed the characters to be in any position

They get shuffled at the end. So the characters can be in any position.

[mitchdenny]

Ah i missed that ignore everything I said.