Quote:
Originally Posted by ixtab
Ok, I may have been a little too pessimistic when speaking of millions of years.
Here's a little thought experiment. From all that I know, the Kindle devices use a 10-character alphanumeric code derived from the serial number of the Kindle. Assuming that only A-Z and 0-9 are valid characters (which is a wrong assumption, because some special characters may also appear), that leaves us with 36^10 = 3,656,158,440,062,976 possible keys.
Now for the sake of simplicity, assume that we can try 1,000,000 keys per second. To try every single key, that means we'd need 3656158440 seconds.
That is 1015600 hours, or 42317 days, or 116 years. If you have 116 computers, you can thus effectively search the entire key space within a year.
The good news is that on average, you'd expect to be done at about half the time. In the best case, you're done immediately, because the first key you try matches, and in the worst case, the very last key you try matches.
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But good encryption such as AES is designed so that you CANNOT generate keys quickly. To search the 10-character (constrained) key space would require generating encryption keys (such as 128-bit AES which is a much larger keyspace) using a slow crypto hash function at a rate far less than 1,000,000 key pairs per second.
The real question is, does kindle ebook DRM use a good (slow) secure hash function for its key generation?