Timeline for Utilizing block cipher (AES) while saving bandwith
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Mar 6 at 17:20 | comment | added | Mikero |
Oh, I interpreted the + in aes(key, fp_encrypted[2:] + second_part) as xor, but that can't be right because fp_encrypted[2:] is 14 bytes and second_part is 2 bytes. You're right.
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| Mar 6 at 16:41 | comment | added | fgrieu♦ | @Mikero: It's not CBC. That would involve XOR or addition, and here there's none: in the pseudocode, + is concatenation. "Ciphertext stealing adapted to ECB" is correct, but hides that the intend is making a 18-byte block cipher, and that adding a third AES would sort of achieve that. Also "has the flaw of using the insecure ECB mode" is correct, but in the context ECB is by design, to keep ciphertext as small as possible, and may not be a flaw at all. | |
| Mar 6 at 14:57 | history | edited | Mikero | CC BY-SA 4.0 |
link to reference on ciphertext stealing
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| Mar 6 at 14:56 | comment | added | Mikero | To be more precise, it looks like they are using CBC mode (second block incorporates xor of first ciphertext block) but with an all-zero IV. I agree with your assessment that this is just ciphertext stealing. | |
| Mar 6 at 5:25 | history | answered | DannyNiu | CC BY-SA 4.0 |