What password characteristic could you require to eliminate the use of LANMAN hashes and restrict the local authentication to NT in a modern Windows system?

Setting a maximum of 14 characters guarantees every password falls within the LM hashing length limit, which ensures LM hashes are always generated rather than preventing them.

The LM hash algorithm splits the password into two 7-character chunks padded to exactly 14 characters, so it is mathematically impossible to compute an LM hash for any password of 15 or more characters. When a password exceeds 14 characters, Windows stores only the NT hash, eliminating the weaker LM hash from the credential store and restricting local authentication to NTLM or NTLMv2.

Including a lowercase character is a complexity requirement and has no effect on which hash algorithm Windows uses; LM vs NT selection is determined solely by password length.

Requiring an uppercase character affects password complexity but does not influence hash type selection; only exceeding the 14-character LM limit prevents LM hash creation.