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Adobe, however, ignored these well-known principles, and instead stored over a hundred million passwords in a reversibly encrypted way, using a terrible choice of encryption methods which exposes a great deal of information about the passwords, and does not involve a salt. This password database was recently obtained by someone and released on the Internet.
 
Adobe, however, ignored these well-known principles, and instead stored over a hundred million passwords in a reversibly encrypted way, using a terrible choice of encryption methods which exposes a great deal of information about the passwords, and does not involve a salt. This password database was recently obtained by someone and released on the Internet.
  
In particular, Adobe used {{w|Triple DES}}, an older encryption algorithm which can still be relatively secure when properly used, but they {{w|Electronic codebook|used it improperly}}. It works on 64-bit (8 character) blocks. Assuming that the passwords are stored in plain ASCII, this means that a sequence of 8 characters in a password which starts on a character position which is a multiple of eight is always encrypted to the same result. Therefore, two passwords starting with "12345678" would start with the same block after being encrypted. Furthermore, this means that you can actually get a very good idea of the length of the password since anything with only one block is a password with length between 1 and 8 characters, and having two blocks implies it has between 9 and 16 characters, etc.
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In particular, Adobe used {{w|Triple DES}}, an older encryption algorithm which can still be relatively secure when properly used, but they [[wikipedia:Electronic codebook|used it improperly]]. It works on 64-bit (8 character) blocks. Assuming that the passwords are stored in plain ASCII, this means that a sequence of 8 characters in a password which starts on a character position which is a multiple of eight is always encrypted to the same result. Therefore, two passwords starting with "12345678" would start with the same block after being encrypted. Furthermore, this means that you can actually get a very good idea of the length of the password since anything with only one block is a password with length between 1 and 8 characters, and having two blocks implies it has between 9 and 16 characters, etc.
  
 
Adobe also stored hints users created for their passwords. That means that an attacker knows not only if the same 8 characters are used for multiple passwords but also has some hints for guessing them. That means that common password portions should be easy to recover and that any user may be "compromised" by someone else using a part of the same password and providing a good hint. As an example, a password having three hints "Big Apple", "Twin Towers" and "If you can make it there" is probably "New York" or a simple variation on that. The weakness here is that no decryption and therefore no hard cracking has to take place, you just group the passwords by their encrypted blocks and try to solve them like a crossword puzzle. These weaknesses have already been used to presumably identify a password used by {{w|Edward Snowden}}, as discussed at [http://7habitsofhighlyeffectivehackers.blogspot.com/2013/11/can-someone-be-targeted-using-adobe.html 7 Habits of Highly Effective Hackers: Can someone be targeted using the Adobe breach?].
 
Adobe also stored hints users created for their passwords. That means that an attacker knows not only if the same 8 characters are used for multiple passwords but also has some hints for guessing them. That means that common password portions should be easy to recover and that any user may be "compromised" by someone else using a part of the same password and providing a good hint. As an example, a password having three hints "Big Apple", "Twin Towers" and "If you can make it there" is probably "New York" or a simple variation on that. The weakness here is that no decryption and therefore no hard cracking has to take place, you just group the passwords by their encrypted blocks and try to solve them like a crossword puzzle. These weaknesses have already been used to presumably identify a password used by {{w|Edward Snowden}}, as discussed at [http://7habitsofhighlyeffectivehackers.blogspot.com/2013/11/can-someone-be-targeted-using-adobe.html 7 Habits of Highly Effective Hackers: Can someone be targeted using the Adobe breach?].

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