Add a separator function for digits and safe symbols

[mitchchn]

Many sites which require at least one symbol also require at least one digit. We can meet this requirement in an elegant and user-friendly way by adding a separator function to the wordlist generator which selects from digits and symbols.

Sample passwords might look like:

Digh@down2booy8thuf
Rak_kac1skop.juth

Care must be taken to not generate separators which are all symbols or all digits. A password with n "chunks" where n > 2 should have at least one symbol and at least one digit.

[robyoder]

Care must be taken to not generate separators which are all symbols or all digits.

Good thing we already have a mechanism for this. :) Generate a 3-char password with required symbols and required digits, nothing "allowed".

[jpgoldberg]

Doing it as described will take some additional logic, as the separator function is called separately for each separation. That is the separator for any two chunks is called independently of any other separator.

So I was thinking instead of having 2 character separators. Each separator would be of the form

digit symbol symbol digit

Note that if we dramatically reduce the number of default symbols in issue #14 then we will also have fewer symbols showing up in passwords. So we may want to address that issue first and then determine what is needed here.

[jpgoldberg]

Good thing we already have a mechanism for this. :) Generate a 3-char password with required symbols and required digits, nothing "allowed".

At the moment, the separator function is called independently at each separation. So we'd need to have the separator function called once to generate a sequence of characters that are then used to insert, one by one, into separator positions. This shouldn't be hard to do (though we need to potentially allow for multi-character separators), but it should be doable.