Timeline for Message encrypted with a LFSR based stream cipher
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Sep 30, 2014 at 5:21 | comment | added | fgrieu♦ | @J0ker: what is meant is that for all integers $n\ge0$, the equation $x_{(n+3)} = x_{(n+2)} \oplus x_n$ holds, where $\oplus$ is exclusive-OR. You are given $x_0$, $x_1$, $x_2$, and can compute $x_3$ (with $n=0$), $x_4$ (with $n=1$), and so on, up to $x_{15}$, which is the last used term of the LFSR output (also the key of the pseudo-OTP, which really is a stream cipher). | |
| Sep 29, 2014 at 17:17 | comment | added | mczraf | The variable 'n' is used to define the recurrence rule for the LFSR algorithm. It is an abstraction, but for your case: n \in [0, 12], since you need a key of length 16. | |
| Sep 29, 2014 at 16:58 | comment | added | Jok3r | What exactly do the "n's" in the problem refer to? | |
| Sep 29, 2014 at 16:00 | history | edited | e-sushi | CC BY-SA 3.0 |
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| Sep 29, 2014 at 15:39 | history | edited | mczraf | CC BY-SA 3.0 |
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| Sep 28, 2014 at 23:09 | vote | accept | Jok3r | ||
| Sep 28, 2014 at 22:35 | comment | added | mczraf | Hint: OTP uses the same computational instruction to perform both encryption and decryption. | |
| Sep 28, 2014 at 22:31 | comment | added | Jok3r | I'm afraid that I don't know what the OTP decryption step looks like... | |
| Sep 28, 2014 at 21:01 | history | answered | mczraf | CC BY-SA 3.0 |