We don't get "£" on our keyboards here. While most password entry systems should accept space, many will not accept tab or ret. While some will accept control characters, many will not, and the input methods vary. Thus, it often isn't very portable to use a password alphabet of more than ~94 characters, and very few people do.
Using linguistic or probabilistic models, almost all passwords have significantly less than lg(2^(#(password alphabet))) bits of entropy (OK, I'm abusing the definition of "entropy" here), although most password crackers aren't this smart.
Longer passwords, when supported by MD5 or Blowfish hashes, will of course take longer to crack, but the entropy per bit will be the same. |
