#sp80063 — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #sp80063, aggregated by home.social.
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Ahahah I just realized that hashcat 7 and NIST 800-63 v4 were released on the same day. I like the symmetry of that.
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Ahahah I just realized that hashcat 7 and NIST 800-63 v4 were released on the same day. I like the symmetry of that.
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Taken together:
Verifiers and CSPs SHOULD permit a maximum password length of at least 64 characters.
and
Verifiers and CSPs SHOULD accept Unicode [ISO/ISC 10646] characters in passwords. Each Unicode code point SHALL be counted as a single character when evaluating password length.
... and that since UTF-8 is max 4 bytes, it seems like 256 bytes might be a nice, practical maximum password byte length.
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Taken together:
Verifiers and CSPs SHOULD permit a maximum password length of at least 64 characters.
and
Verifiers and CSPs SHOULD accept Unicode [ISO/ISC 10646] characters in passwords. Each Unicode code point SHALL be counted as a single character when evaluating password length.
... and that since UTF-8 is max 4 bytes, it seems like 256 bytes might be a nice, practical maximum password byte length.
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If you're using two factors everywhere ... your passwords can be shorter.
Verifiers and CSPs SHALL require passwords that are used as a single-factor authentication mechanism to be a minimum of 15 characters in length. Verifiers and CSPs MAY allow passwords that are only used as part of multi-factor authentication processes to be shorter but SHALL require them to be a minimum of eight characters in length.
(but in practice, most enterprises aren't MFA everywhere yet internally -- and that matters)
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If you're using two factors everywhere ... your passwords can be shorter.
Verifiers and CSPs SHALL require passwords that are used as a single-factor authentication mechanism to be a minimum of 15 characters in length. Verifiers and CSPs MAY allow passwords that are only used as part of multi-factor authentication processes to be shorter but SHALL require them to be a minimum of eight characters in length.
(but in practice, most enterprises aren't MFA everywhere yet internally -- and that matters)
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Also, for those folks who are using the entire HIBP corpus to block billions of passwords at the point of creation by the user, take note (I've been saying this for years) -- the purpose of such denylists is to defend against online / interactive attack:
NIST SP 800-63b:
Since the blocklist is used to defend against brute-force attacks and unsuccessful attempts are ratelimited, the blocklist SHOULD be of sufficient size to prevent subscribers from choosing
passwords that attackers are likely to guess before reaching the attempt limit.... and therefore (emphasis mine):
Excessively large blocklists are of little incremental security benefit because the blocklist is used to defend against online attacks, which are already limited by the throttling requirements described in Sec. 3.2.2.
Blocking billions of potential passwords is also a UX nightmare, because most implementations of full HIBP blocking don't do enough of this:
Verifiers SHALL offer guidance to the subscriber to help the subscriber choose a strong
password. This is particularly important following the rejection of a password on the blocklist as it discourages trivial modifications of listed weak passwords [Blocklists].(In context, this is about secrets that must be memorized; advising users to use a password vault is of course also table stakes otherwise!)
Should users be prevented from reusing their own passwords that have been leaked elsewhere? Definitely (but doing so is tricky). But should a user be prevented from using a password that anyone has ever used anywhere? Arguably ... but at what cost?
https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-63B-4.pdf
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Also, for those folks who are using the entire HIBP corpus to block billions of passwords at the point of creation by the user, take note (I've been saying this for years) -- the purpose of such denylists is to defend against online / interactive attack:
NIST SP 800-63b:
Since the blocklist is used to defend against brute-force attacks and unsuccessful attempts are ratelimited, the blocklist SHOULD be of sufficient size to prevent subscribers from choosing
passwords that attackers are likely to guess before reaching the attempt limit.... and therefore (emphasis mine):
Excessively large blocklists are of little incremental security benefit because the blocklist is used to defend against online attacks, which are already limited by the throttling requirements described in Sec. 3.2.2.
Blocking billions of potential passwords is also a UX nightmare, because most implementations of full HIBP blocking don't do enough of this:
Verifiers SHALL offer guidance to the subscriber to help the subscriber choose a strong
password. This is particularly important following the rejection of a password on the blocklist as it discourages trivial modifications of listed weak passwords [Blocklists].(In context, this is about secrets that must be memorized; advising users to use a password vault is of course also table stakes otherwise!)
Should users be prevented from reusing their own passwords that have been leaked elsewhere? Definitely (but doing so is tricky). But should a user be prevented from using a password that anyone has ever used anywhere? Arguably ... but at what cost?
https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-63B-4.pdf
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New NIST SP800-63b on password length (seems solid):
Users should be encouraged to make their passwords as long as they want within reason. Since the size of a hashed password is independent of its length, there is no reason to prohibit the use of lengthy passwords (or passphrases) if the user wishes. However, extremely long passwords (perhaps megabytes long) could require excessive processing time to hash, so it is reasonable to have some limit.
https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-63B-4.pdf
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New NIST SP800-63b on password length (seems solid):
Users should be encouraged to make their passwords as long as they want within reason. Since the size of a hashed password is independent of its length, there is no reason to prohibit the use of lengthy passwords (or passphrases) if the user wishes. However, extremely long passwords (perhaps megabytes long) could require excessive processing time to hash, so it is reasonable to have some limit.
https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-63B-4.pdf
