Ya know that’s what they say, but I’m not so sure - is your dictionary-based brute-forcer doing strings of three words together? Allowing for interspersed special characters between? The sheer character length of three truly random dictionary words in a row is already staggeringly high amounts of entropy - I’m not sure I need to be worried about an attacker capable of that kind of sheer number-buggery.
On your bikelock you have a 3 character code with and alphabet of 0-9. So 10^3 = 1000 possible combinations.
If you pick 3 random words out of a dictionary with 40k words, there are 40000^3 possible combinations. (64 000 000 000 000).
Depending on how the password is hashed a 1000$ machine might be able to test anywhere from like 10 to 10 000 000 000 000 hashes per second. (100 billion hashes per second are more realistic)
So a 3 word password might be safe for a very very long time or cracked in seconds.
I’m sure they are ever since this comic came out. It is a very large amount of entropy, but it is still far, far less than an equivalent amount of random characters. Honestly, you do you. If passwords are properly hashed and password attempts are not unlimited and as fast as possible, you’re basically fine.
If it’s three words together, they can’t really verify one word by itself. That’s why it’s secure. They would have to test all combinations of three words which would take forever. The reason dictionary attacks work is because people use one word (password), a simple modification of a word (password1!), or a simple common phrase (openssesame1!). The technique is just hoping someone was being ignorant or negligent. But you’re right, they would have to crack all three words in sequence, which means testing all combinations of three words. That’s hard to do.
This is why social engineering is much more important. To even get close to cracking all three words they would have to get to know you, assuming you’re using something related to yourself like a relative’s name, your favorite movie, an inside joke between friends. A targeted attack against you will probably start with social engineering rather than brute forcing your passwords. A random attack is like people who walk down the street looking for an unlocked car door. They’re just trying to find someone who isn’t secure, not you specifically, and therefore probably wouldn’t start with getting to know you.
You want your dictionary to be as small as possible. You can scrape Oxford to a text file and use that, but you’re wasting so much time on thousands of words that are unlikely to be relevant. So rather than just using random words they use common words, phrases, and variations of those in their dictionaries. An actual dictionary probably wouldn’t contain correct, horse, battery, or staple. It’s more likely to be password, password1, password2, etc and then the other common stuff people use for passwords. If you’re a targeting someone specific, you would make a custom dictionary specific to their life.
Good info! And that’s exactly what I meant - a word is weak, but several randomized words together is pretty crazy strong. Slightly less than random letters, but much easier to type in memorize when the situation calls for it.
even 4 words with one common substitution fucks up dictionary attack, cause you expand the search space 3-10 fold per word. although one have to have at least one relatively uncommon word (from 20k vocabulary, not 2k vocabulary)
Weak to dictionary attacks. better make it six words
Ya know that’s what they say, but I’m not so sure - is your dictionary-based brute-forcer doing strings of three words together? Allowing for interspersed special characters between? The sheer character length of three truly random dictionary words in a row is already staggeringly high amounts of entropy - I’m not sure I need to be worried about an attacker capable of that kind of sheer number-buggery.
It’s about combinatorics.
On your bikelock you have a 3 character code with and alphabet of 0-9. So 10^3 = 1000 possible combinations.
If you pick 3 random words out of a dictionary with 40k words, there are 40000^3 possible combinations. (64 000 000 000 000).
Depending on how the password is hashed a 1000$ machine might be able to test anywhere from like 10 to 10 000 000 000 000 hashes per second. (100 billion hashes per second are more realistic)
So a 3 word password might be safe for a very very long time or cracked in seconds.
A 4 word password will take 40000 times as long.
I’m sure they are ever since this comic came out. It is a very large amount of entropy, but it is still far, far less than an equivalent amount of random characters. Honestly, you do you. If passwords are properly hashed and password attempts are not unlimited and as fast as possible, you’re basically fine.
If it’s three words together, they can’t really verify one word by itself. That’s why it’s secure. They would have to test all combinations of three words which would take forever. The reason dictionary attacks work is because people use one word (password), a simple modification of a word (password1!), or a simple common phrase (openssesame1!). The technique is just hoping someone was being ignorant or negligent. But you’re right, they would have to crack all three words in sequence, which means testing all combinations of three words. That’s hard to do.
This is why social engineering is much more important. To even get close to cracking all three words they would have to get to know you, assuming you’re using something related to yourself like a relative’s name, your favorite movie, an inside joke between friends. A targeted attack against you will probably start with social engineering rather than brute forcing your passwords. A random attack is like people who walk down the street looking for an unlocked car door. They’re just trying to find someone who isn’t secure, not you specifically, and therefore probably wouldn’t start with getting to know you.
You want your dictionary to be as small as possible. You can scrape Oxford to a text file and use that, but you’re wasting so much time on thousands of words that are unlikely to be relevant. So rather than just using random words they use common words, phrases, and variations of those in their dictionaries. An actual dictionary probably wouldn’t contain correct, horse, battery, or staple. It’s more likely to be password, password1, password2, etc and then the other common stuff people use for passwords. If you’re a targeting someone specific, you would make a custom dictionary specific to their life.
If you pick 3 randon words out of 40000 that’s less entropy than a 8 random character password with only letters and numbers.
Good info! And that’s exactly what I meant - a word is weak, but several randomized words together is pretty crazy strong. Slightly less than random letters, but much easier to type in memorize when the situation calls for it.
What if you just add a letter after each word. Like correct a horse b battery c staple d.
I imagine single letters are in the dictionary, but that would double the amount of words
What if you mix languages or do they brute force multiple languages at the same time?
I’ll be real I tried looking up dictionaries used in attacks, ran into the slightest amount of resistance, and immediately stopped caring. Wikipedia has a list of attacks with links if you want to find out yourself
What if I add Tr0ub4dor&3 to my dictionary?
or proper nouns that arent in dictionaries
even 4 words with one common substitution fucks up dictionary attack, cause you expand the search space 3-10 fold per word. although one have to have at least one relatively uncommon word (from 20k vocabulary, not 2k vocabulary)