Timeline for Alter plaintext through IV in block cipher AES in CBC mode
Current License: CC BY-SA 4.0
15 events
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| Jul 7, 2020 at 22:03 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Mar 9, 2020 at 21:03 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Nov 10, 2019 at 21:01 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Jul 13, 2019 at 20:02 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Mar 15, 2019 at 20:01 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Feb 13, 2019 at 19:58 | answer | added | Maarten Bodewes♦ | timeline score: 2 | |
| Feb 10, 2019 at 16:00 | comment | added | kelalaka |
@IlmariKaronen What I've understood, he wants to modify the IV in a way that the original plaintext SEND ENCRYPTED DATA|Padding_1 will turn into SEND DATA|padding_2. But the problem is the second block. SEND ENCRYPTED 15 char. One can change SEND DATA by changing the IV. But the second block is problematic. He needs to modify the first ciphertext, too. So, he must first consider changing the $C_1$ then concentrate on IV. (assuming that 16 char is encrypted per block)
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| Feb 10, 2019 at 15:59 | comment | added | Ilmari Karonen | BTW, here's a hint to begin with: start by figuring out which padding scheme is used. (I'd guess it's most likely PKCS#7, but there are several other possibilities as well.) Then apply the padding to both plaintexts. Now try to figure out what else, besides bit flipping, you'd need to do to turn one into the other. Can you do that just by manipulating the ciphertext? | |
| Feb 10, 2019 at 15:49 | comment | added | Ilmari Karonen | @kelalaka: I would say that this question can be interpreted and answered in a way that is on-topic here (i.e. the answer does not necessarily need to include any code). Whether such an answer would actually help the OP is still somewhat unclear to me. | |
| Feb 10, 2019 at 12:33 | comment | added | kelalaka | This is off-topic here. programming Questions belongs to SO. | |
| Feb 10, 2019 at 12:29 | comment | added | nachofest | @llmari Karonen please check my new edit, thank you | |
| Feb 10, 2019 at 12:28 | history | edited | nachofest | CC BY-SA 4.0 |
added 968 characters in body
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| Feb 10, 2019 at 3:02 | comment | added | Ilmari Karonen | Also, does the modified plaintext have to be exactly "SEND THE DATA"? Because it would be easier to do this if you didn't have to change the length of the plaintext. (You can probably still do it in this case anyway, but the details will depend on the padding scheme used.) | |
| Feb 10, 2019 at 2:58 | comment | added | Ilmari Karonen | Some more details would be welcome. Exactly what have you tried, and what kind of "troubles" have you had? | |
| Feb 10, 2019 at 0:56 | history | asked | nachofest | CC BY-SA 4.0 |