NIST Recommends Some Common-Sense Password Rules
NIST’s second draft of its “SP 800-63-4“—its digital identify guidelines—finally contains some really good rules about passwords:
The following requirements apply to passwords:
- lVerifiers and CSPs SHALL require passwords to be a minimum of eight characters in length and SHOULD require passwords to be a minimum of 15 characters in length.
- Verifiers and CSPs SHOULD permit a maximum password length of at least 64 characters.
- Verifiers and CSPs SHOULD accept all printing ASCII [RFC20] characters and the space character in passwords.
- Verifiers and CSPs SHOULD accept Unicode [ISO/ISC 10646] characters in passwords. Each Unicode code point SHALL be counted as a signgle character when evaluating password length.
- Verifiers and CSPs SHALL NOT impose other composition rules (e.g., requiring mixtures of different character types) for passwords.
- Verifiers and CSPs SHALL NOT require users to change passwords periodically. However, verifiers SHALL force a change if there is evidence of compromise of the authenticator.
- Verifiers and CSPs SHALL NOT permit the subscriber to store a hint that is accessible to an unauthenticated claimant.
- Verifiers and CSPs SHALL NOT prompt subscribers to use knowledge-based authentication (KBA) (e.g., “What was the name of your first pet?”) or security questions when choosing passwords.
- Verifiers SHALL verify the entire submitted password (i.e., not truncate it).
Hooray.
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p id=”powered”>Sidebar photo of Bruce Schneier by Joe MacInnis.
