fix author label with more than 6 author initials

[nglaeser]

The CryptoBib manual states that the author label rule is

Papers with four or more authors ==> First letter of each author's last name (up to 6)

(italics mine). This PR fixes 3 entries I found for 2 papers total whose labels didn't follow this rule:

• PoPETS:MSHLHSHHMNC18 -> PoPETS:MSHLHS18
• SP:CHIKMRsVW21 -> SP:CHIKMR21
• EPRINT:CHIKMRsVW20 -> EPRINT:CHIKMR20

[nglaeser]

@michelabdalla This PR has been open for a while, is there an issue I need to fix in order for it to be merged?

[michelabdalla]

Hi @nglaeser, there are currently some other inconsistencies related to the labeling rule for papers with more than 6 authors and we are trying to figure out the best way to address it without causing problems.

FYI, @fabrice102 ran a test in late July and found out the following:
22 papers with >6 authors have <6 initials in key
821 papers with >6 authors have =6 initials in key
1389 papers with >6 authors have >6 initials in key

[ludopulles]

I found some more quirks apart from what that 6 author format script gave, like:

• [EC:Burmester90a] should be [EC:BurDes90],
• [EPRINT:UnrDom12] should be [EPRINT:Unr12], giving two entries the same key, so there should actually be [EPRINT:Unr12a] and [EPRINT:Unr12b].

See https://github.com/ludopulles/cryptobib_tools/blob/master/format_entry.py for the script to fix those, it might need the modified lib in https://github.com/ludopulles/cryptobib_lib to succesfully output the bibtex file.

My plan is to make a pull request for https://github.com/ludopulles/crypto_db/tree/fix-252 to address the issue raised here, when/if #260 is merged.

[nglaeser]

@michelabdalla I see, thank you for the response!