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Comments on Are "strong passwords" at all meaningful?
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Are "strong passwords" at all meaningful?
Whenever registering to diverse sites on the net, you are often forced to enter a so called "strong password", which would ideally contain both upper case letters, lower case letters, digits, and some other character like punctuation. As hard to remember as possible.
What I don't understand from a software development point of view is how these characters would make that much of a difference.
All of it seems to assume that a hacker trying to break a password would utilize so-called brute force. That is: try "A", try "B" ... "try AA" and so on. The more variations, the longer it takes to execute the brute force algorithm.
If I have a password of up to 10 capital letters A to Z plus "empty", that's 27 combinations, for a total of 2710 combinations.
As opposed to having a 10 letter password in the whole UTF8/ASCII 7 bit range, 127 combinations - 32 non-printable + 1 empty = 96, for a total of 9610 combinations.
Sure, a significant difference, astronomical even. But... if they would execute a brute force across TCP/IP they can maybe try one combination every millisecond or something, assuming great bandwidth. Worst case scenario for the 2710 scenario is then 57 days. Some 4 weeks on average. Assuming there's no big latency or packet drop for a significant lower bandwidth, in which case this isn't really feasible at all.
I don't see anyone setting up a brute force operation for that in order to access John Doe's Gmail account or whatever... it is already too much of an obstacle. Unless they hope to get lucky on the initial bunch permutations, which can of course happen.
Assuming that brute force is actually what's used, which sounds quite unlikely to me. Instead of something else entirely: keyword logging, packet sniffing, the human factor ("Hi this is your bank please send us your password") etc etc.
So is the usefulness of this whole "strong password" thing just an urban legend, where companies force us to memorize ridiculously hard to remember passwords for no real gain? Why is the number of symbol table combinations in the password oh so important on almost any Internet site these days?
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The assumption of 1k attempts/s is wishful thinking, as is the idea that a hacker will go on mail.google.com and try to guess your login (they would get a captcha after like 5 failed attempts).
Password security comes into play when someone steals the whole table of all accounts and password hashes from the website operator, and then they start trying to hash different putative passwords to see if any of them match. This is very similar to cryptocurrency mining, so it's probably fair to say that about $1000 can get you hardware that can do about 1 billion password hashes/s.
When the website discovers their hashes are stolen and offered for sale on black market, the reasonable thing to do is invalidate all current passwords so that all users will be forced to reset password (using phone, email...) at next login. This will make the hashes useless. However, it will take some time for the site operator to find out, so if you have a very easy password the cracker could find it very quickly, use it and do some harm. If your password takes at least a few weeks, there's a good chance that by the time the cracker solves it, it will not be valid. I think this is the main reason why they require strong passwords.
By strong here I am thinking of 16 random chars A-Za-z0-9. This is about 95 bits, and even if you had a year you would need to try 10^15/s which is not feasible with today's tech. If/when better techs comes out the website admins would switch to a harder hash type, which would still take long even on the newer hardware.
companies force us to memorize ridiculously hard to remember passwords
They assume you will use a password manager, rather than memorizing it.
I don't see anyone setting up a brute force operation for that in order to access John Doe's Gmail account or whatever
A Gmail account is probably very valuable, because it can be used to send a lot of spam that will be treated as legitimate because it's coming from Gmail, and also people usually have Gmail set up for password recovery in other accounts so you can gain access to those from the Gmail. However, Google uses MFA, so just knowing the password won't be enough to gain access to it.
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