This is a substitution cipher and it's not very secure. Consider what we can do if we compromise the Amazon password that's given as an example on the website: sh(/J3HqAfQsu..u.rqf Since the password came from Amazon, we know that the last 6 characters are "Amazon," which tells us that: . = A u = M r = Z q = O f = N Now we can start attacking the codeword, which are the characters between the 8-character "space bar c…
Aren't the cards all different? I assumed it would be a one-time-pad which is much more secure than a simple substitution.
If you're on linux you can usually just do: shuf -n 5 /usr/share/dict/words On Mac OS X you need coreutils for shuf, which you can get from brew (it's called gshuf once installed).
To get rid of the newlines shuf -n 4 /usr/share/dict/words | xargs | sed 's/ //g'
Besides other problems (like not working with certain password requirements), this particularly doesn't work when a site forces you to reset your password because of a breach or time limit or who knows what. (Yahoo just forced a mandatory password reset on me today, without even giving a reason except to "protect my account".)
Then you've got to remember -- are you now on amazon3 or amazon4 or gmail4 or gmail5? And then it defeats the whole purpose of the card.
This is a substitution cipher and it's not very secure. Consider what we can do if we compromise the Amazon password that's given as an example on the website: sh(/J3HqAfQsu..u.rqf Since the password came from Amazon, we know that the last 6 characters are "Amazon," which tells us that: . = A u = M r = Z q = O f = N Now we can start attacking the codeword, which are the characters between the 8-character "space bar c…
Aren't the cards all different? I assumed it would be a one-time-pad which is much more secure than a simple substitution.
Yes, they are different. But that just makes it a substitution cipher with unique keys.
A one time pad requires a key as long as all the messages you want to encode since each key bit is only used once.
This is a substitution cipher and it's not very secure. Consider what we can do if we compromise the Amazon password that's given as an example on the website: sh(/J3HqAfQsu..u.rqf Since the password came from Amazon, we know that the last 6 characters are "Amazon," which tells us that: . = A u = M r = Z q = O f = N Now we can start attacking the codeword, which are the characters between the 8-character "space bar c…
What is the point of decoding this back into the user's original "ENIGMA" and "AMAZON" strings? In this case, "sh(/J3HqAfQsu..u.rqf" is the user's password. If you have that, there is nothing to crack. Edit: I see "Combine with another compromised password, and we're coming dangerously close to being able to generate a password for any arbitrary website.", which means that if an attacker could obtain a couple of thes…
Not necessarily, if this card ever gets popular enough that it's worth the trouble in a first place, cracker can simply presume that at least some of the leaked passwords are created with it. He can then just go though the passwords one by one, decipher the last segment (this can be done very quickly), substitute it with the encrypted email domain (the email is also in the leaked DB) and check if the login works. If vulnerable passwords are in the DB they will all be found, and fairly fast, too. Once the cracker gets access to you email account all your bases are belong to him, he can then get even into the sites where you didn't use the password card at all, simply by using the forgotten pass link.
This is a substitution cipher and it's not very secure. Consider what we can do if we compromise the Amazon password that's given as an example on the website: sh(/J3HqAfQsu..u.rqf Since the password came from Amazon, we know that the last 6 characters are "Amazon," which tells us that: . = A u = M r = Z q = O f = N Now we can start attacking the codeword, which are the characters between the 8-character "space bar c…
It's vulnerable to a known ciphertext attack, yes. But the assumption of password usage is that the password itself is never stored - the ciphertext of this cipher should itself not be available to an attacker. An attacker looking to bruteforce a compromised file of passwords is going to struggle to figure out that your password is sh(/J3HqAfQsu..u.rqf. Even if they do find it, what would tip them off that it was gen…
An attacker might setup a malicious site to collect passwords. They could also modify the server to record passwords when the user logs in.
This is a substitution cipher and it's not very secure. Consider what we can do if we compromise the Amazon password that's given as an example on the website: sh(/J3HqAfQsu..u.rqf Since the password came from Amazon, we know that the last 6 characters are "Amazon," which tells us that: . = A u = M r = Z q = O f = N Now we can start attacking the codeword, which are the characters between the 8-character "space bar c…
What is the point of decoding this back into the user's original "ENIGMA" and "AMAZON" strings? In this case, "sh(/J3HqAfQsu..u.rqf" is the user's password. If you have that, there is nothing to crack. Edit: I see "Combine with another compromised password, and we're coming dangerously close to being able to generate a password for any arbitrary website.", which means that if an attacker could obtain a couple of thes…
> If you have that, there is nothing to crack.
Alice is a system administrator of xyz.com. She has access to the password that Bob uses on xyz.com. By reverse engineering Bob's password on xyz.com, Alice can then attack Bob's account on pqr.com.
If the end goal is to turn a long, comprehensible password like "correcthorsebatterystaple" into something not remotely subject to a dictionary attack, then merely shifting your fingers over on the keyboard by one key is much more convenient: "vpttrvyjptdrnsyyrtudys[;r". Sure, it suffers from the same short-comings as mentioned above (it's still a substitution cipher), but it's much more convenient than going to the card for each individual letter. "vottrvyjptdrnsyyrtudys[;r" is as quick to type as correcthorsebatterystaple but much™ more™ secure™.
It's rather ironic this site is all about strong security, when their SSL/TLS settings are terrible. (Including being open to the POODLE and OpenSSL CCS vulnerabilities)