Timeline for One time pad - how is the difference in length between the plain text & the OTP handled?
Current License: CC BY-SA 4.0
22 events
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| S Nov 11, 2020 at 9:13 | history | bounty ended | user93353 | ||
| S Nov 11, 2020 at 9:13 | history | notice removed | user93353 | ||
| Nov 11, 2020 at 9:13 | vote | accept | user93353 | ||
| Nov 5, 2020 at 3:44 | history | edited | user93353 | CC BY-SA 4.0 |
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| Nov 5, 2020 at 3:30 | history | edited | user93353 | CC BY-SA 4.0 |
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| Nov 5, 2020 at 3:03 | answer | added | Richie Frame | timeline score: 2 | |
| Nov 4, 2020 at 9:00 | history | tweeted | twitter.com/StackCrypto/status/1323912888793374722 | ||
| S Nov 4, 2020 at 8:20 | history | bounty started | user93353 | ||
| S Nov 4, 2020 at 8:20 | history | notice added | user93353 | Authoritative reference needed | |
| Nov 2, 2020 at 18:53 | history | removed from network questions | SEJPM | ||
| Nov 2, 2020 at 16:21 | history | became hot network question | |||
| Nov 2, 2020 at 13:03 | comment | added | Marc Ilunga | An OTP (theoretically) builds a "secure" channel given a authenticated one. The quoted "secure" is to stress that you have to leak the length to the adversary. In many cases this will break confidentiality. To avoid this, you'll need to define an invective padding scheme so that all messages have the same length. Note that a padding scheme is equivalent to the encoding scheme described before. Hence "not have worry of maximum lengths". | |
| Nov 2, 2020 at 12:48 | comment | added | user93353 | @MarcIlunga - I am not looking to avoid maximum length considerations. I am interested in what happens in the case where each one time pad a maximum length, is used only for 1 encryption & the message is shorter than the OTP | |
| Nov 2, 2020 at 12:29 | comment | added | Marc Ilunga | You might get away from the length issues by doing the following: Let $N$ be the number of all possible messages and $M$ the message space. Define a bijective mapping $\phi: M \to Z_N$. The your pad book can simply be strings of elements in $Z_N$. To OTP-encrypt $m$: apply $\phi$ and perform addition of encoded message and the pad mod $N$. To decrypt do the reverse: substract then decide. This would still be an OTP but without the maximum lengths considerations. | |
| Nov 2, 2020 at 8:58 | history | edited | user93353 | CC BY-SA 4.0 |
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| Nov 2, 2020 at 8:51 | answer | added | kelalaka | timeline score: 5 | |
| Nov 2, 2020 at 8:42 | review | Close votes | |||
| Nov 3, 2020 at 22:28 | |||||
| Nov 2, 2020 at 8:39 | comment | added | user93353 | @kelalaka - I am asking where your sender & receiver have a whole book of one time pads. Each page of the book is supposed to be for a particular day. So each page is a fixed length OTP. In this case, if the plaintext is smaller than the OTP, how is that handled | |
| Nov 2, 2020 at 8:37 | comment | added | user93353 | @kelalaka - No, I am not asking how the OTP is working. So the rest of your comment doesn't make sense to me. | |
| Nov 2, 2020 at 8:31 | comment | added | user93353 | @kelalaka - they key is not depleted. I am asking for the case where the key is longer than the plaintext. | |
| Nov 2, 2020 at 8:27 | comment | added | user93353 | @kelalaka What does "Halt the messaging" mean? What does "face the key reuse" mean? The wikipedia example with Hello as plaintext seems to use a key which is the same length as the plaintext | |
| Nov 2, 2020 at 8:20 | history | asked | user93353 | CC BY-SA 4.0 |