Security Basics mailing list archives
RE: Suggested "safe" password length
From: JohnNicholson () aol com
Date: Fri, 14 Nov 2003 16:27:01 -0500
I think this is correct. As I understand it, the password encryption function breaks passwords into 7-character blocks before encrypting them. The impact of this is that for an 8-character password you end up with two blocks - one 7 characters and one 1 character, each encrypted with the same function. Breaking the encryption on the single character is trivial, and then you know how to break the encryption on the 7 character remainder. By inference, no attack should ever need to break more than a 7-character string (because having broken one means you have the key to break the others), and having multiple 7-character strings just gives an attacker 2 (or more) chances to hit a combination using a brute force attack. So, I think the best length is 7-characters, using non-dictionary combinations that include special characters. At least, this is the theory I've been using. If I'm wrong, I hope someone will let me know so I can change paradigms. John In a message dated 11/13/2003 11:37:03 PM Eastern Standard Time, "Michael LaSalvia" <mike () genxweb net> writes:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Many people say 8 or more but I have read some where that multiples of 7 are the best to use. It may have been in a class or something I heard that. - -----Original Message----- From: Ashish Sharma [mailto:ashishs () iitg ernet in] Sent: Thursday, November 13, 2003 3:06 AM To: security-basics () securityfocus com Subject: Suggested "safe" password length Hi, I wanted to have an idea about what should be the suggested range of password lengths and if there is any upper bound. I was told that there is a range upto which your password is encrypted and beyond which the characters are futile. I work on a linux environment with md5 encryption of passwords enabled. TIA Ashish
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Current thread:
- Re: Suggested "safe" password length, (continued)
- Re: Suggested "safe" password length Peter Schawacker (Nov 18)
- Re[2]: Suggested "safe" password length Vishal (Nov 20)
- Re: Suggested "safe" password length Anders Reed-Mohn (Nov 20)
- Re[2]: Suggested "safe" password length Vishal (Nov 21)
- Re: Suggested "safe" password length Hollis Johnson (Nov 17)
- Re: Suggested "safe" password length Steve (Nov 17)
- RE: Suggested "safe" password length dave kleiman (Nov 17)
- RE: Suggested "safe" password length Ben Cain (Nov 17)
- RE: Suggested "safe" password length dave kleiman (Nov 17)
- Re: Suggested "safe" password length Simon Gray (Nov 17)