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8

Historically, there did exist a benefit to using a language that the adversary was not familiar with. The name for this is code talkers, and the most famous ones (at least in the USA) are the Navajo code talkers of World War II. The idea was to defeat attacks that relied on statistics about the language used in the plaintext. In modern cryptography, ...


7

This is identical with CTR mode encryption with a MAC. That's known to be secure. It doesn't say in your question if: the Ai blocks are completely unique; the header is included in the MIC calculation. If those preconditions are met then I don't see any issue with the protocol. The first one I cannot verify but seems likely, the second one is certainly ...


4

If you're referring to a classical cipher, it might complicate frequency analysis and other such techniques. For a modern cipher, it makes no difference. Modern ciphers operate on arbitrary patterns of information. Ideally, the ciphertext of a modern cipher should have no relation of any kind to the associated plaintext, other then the key.


4

The XOR state is irreversible without the proper key which is what I understand, so whats the point of all of the other operations that happen on the key? Suppose all we had was secret keys and the XOR operation. Well, actually, it is possible to build a secure cipher out of that, called the one time pad. One time pads offer perfect secrecy, but suffer ...


3

All of the mathematical operations within the s-boxes, shift row, and mix column should be known to the attacker, correct? Yes, see Kerckhoff's principle I understand they could be hard to calculate but aren't they static operations for the most part? I'm interpreting "static operations" to mean subBytes + shiftRows + mixColumns + addRoundKey, and that ...


2

A block cipher mode is an algorithm used along with a block algorithm to encrypt arbitrary size plaintext, providing both confidentiality and authentication. A single block cipher operates only on a fixed block length. It is not alone enough to encrypt larger plaintexts. However, a single block encryption can work as a black box in the Random Oracle Theory. ...


2

Around and about one hundred years ago, your idea would surely have made sense… but nowadays, modern technology and evolved cryptanalytic techniques are too smart to have a real problem coping with something like that. (Also see my related answer to “Why was the Navajo code not broken by the Japanese in WWII?”) Even when we completely ignore Kerckhoffs’ ...


2

The distance of the code word is the minimum number of bit flips that transforms one codeword into another. It's just the minimum of all possible hamming distances between the codes. Also you can define the weight of a codeword to be the distance from the zero vector. For your code it looks like $d = 2$.


2

First use the TID as input for a KDF to generate one or more tag specific keys, using a static, symmetric master key stored in the initialization software and gadget. Use one of these keys to obtain access. Use another for verification of the tag. During initialization derive and set the access key (s). Then create a HMAC over a static value (or multiple ...


2

If I am correct, and you can just the ESN has the implicit IV, is doing so compliant with the standards? No, it would not be compliant with the RFC. The RFC clearly states that there must be 8 bytes of IV payload immediately in front of the ciphertext (see section 3). Omitting those 8 bytes would not allow interoperability with standard implementations of ...


1

Yes, there is the one-time MAC. This is a scheme which ensures that an adversary (even one with infinite computational resources) has a negligible chance of altering the message or forging a fake message without detection.



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