Cryptography Report Claims Eight New Spectre-Class Vulnerabilities Impact Intel And ARM Processors |
- Report Claims Eight New Spectre-Class Vulnerabilities Impact Intel And ARM Processors
- Need a little help ( actually a lot of help) with some of these questions... (not trying to cheat)
- Is this a valid use of ECB mode?
- How would you break this insecure cipher based on a rubiks cube?
- Asylo: An open and flexible framework for enclave applications
| Report Claims Eight New Spectre-Class Vulnerabilities Impact Intel And ARM Processors Posted: 04 May 2018 04:04 AM PDT |
| Need a little help ( actually a lot of help) with some of these questions... (not trying to cheat) Posted: 04 May 2018 07:17 PM PDT Okay so hi friends, I am an ISY major who needs a little help understanding a few really hard questions on an online crypto quiz my teacher's had up for months. My semester ends tomorrow at noon and I've been working on it for about a month or two and I need a little help understanding certain questions. Question A:
ZKDW LV D IRUXP? WZR-XP SOXV WZR-XP! I've researched this for hours and I can't figure out which cipher method this is. I think it's substitution, but I'm not positive and when I try substitution it's wrong. Question B: It is WWII and you have intercepted a message from the Germans on the European mainland. You know the enemy Enigma machines are the Wehrmacht Enigma I with B reflector. You already have the Heer (Army) secret daily key sheet, which was acquired from a captured German. The translation of the sheet can be found in the file "enigma_codesheet.txt". The Message: EHZ XAF TFEVT XUYRQ NCDKL FMDWC SYKUW ISINC WBQEZ OO What is the answer in the word at the end of the message? It is uppercase and 8 characters long. christ this one makes me want to cry lol I downloaded the enigma emulator and tried to do it but I literally cannot figure this out or how to do the rotors and reflectors????? Question C:
So I know that ECB is used when plaintext is separated into multiple blocks of data, and each block is independently encrypted, and that every plaintext value will always result in the same ciphertext value every time... so does this mean that the two highlighted chunks are the same plaintext value in both packets?? I know it sounds stupid but I just want to be sure and understand this correctly lol Question D: In order to be safe, a stream cipher must never use the same key twice. To prevent this from happening, a static key is combined with a changing initialization vector. In this example, we will use the same key, and resultant key stream, to demonstrate that point. Normal encryption and decryption happens like this: ClearText XOR KeyStream = CipherText CipherText XOR KeyStream = ClearText Since XOR is transitive, we can get the key stream like this if know the clear text and can observe cipher text: CipherText XOR ClearText = KeyStream This means the key stream needs to change, hence the reason for the changing key requirement. For a given key and key stream, if the attacker knows one combination of clear text and cipher text, he can decrypt any message that uses the same key (and key stream). Use this to crack CipherText2 and get the one word flag in uppercase characters: ClearText1: This is the first clear text CipherText1 (hex encoded): DF89A7E83396463D8705DFBA364AA509649FE271F766D2CA3C6F00C5 CipherText2 (hex encoded): DF89ABBB7593547AD304C9A070659B3B5DF6CF5ADD54 I'm not exactly sure what to do here...can someone please explain? any help would be so much appreciated...thank you!!! [link] [comments]  |
| Is this a valid use of ECB mode? Posted: 04 May 2018 09:08 AM PDT Alice wants to give Charlie a 512-bit hash from some cryptographic hash function. But Charlie isn't around today, so she leaves the hash with Bob. Unfortunately, Bob is not allowed to know the hash, so Alice has to encrypt it first using a secret key she already shares with Charlie. But, Bob wants to know he's getting data that's really from Alice. Bob and Charlie both have her public key. Message integrity is assured by signing the ciphertext with Alice's private key, which Bob and Charlie can validate. The ciphertext is generated using AES in ECB mode, because a) there's no need for AEAD since Bob can't use it without the key and we already have the signature, and b) the likelihood of identical blocks happening in the hash is extremely low (once in every 264 blocks, if I'm not mistaken, which I expect to be far beyond the lifespan of the key). Is this a reasonable use of ECB mode? edit: A point I forgot to mention: there's more than one each of Alice, Bob and Charlie. The Bobs want to deduplicate identical hashes sent by the Alices, without knowing the hashes themselves, or possessing the ability to trick other Bobs into accepting fake records. The Charlies must be able to obtain the hash itself, and not merely a derivative of the hash. [link] [comments]  |
| How would you break this insecure cipher based on a rubiks cube? Posted: 04 May 2018 11:59 AM PDT Hello, I am a crypto-student and recently i tought about this silly crypto system that im having trouble deciding on how to start breaking it. The system is simple: Get a rubicks cube, glue a character of your message in every cell of it(Given your message has 54 characters), in an order such that you can read the message easily and the colors are hidden, then and apply an arbitrary number of operations on the rubicks cube getting in the end a cube with all the characters of your message permuted. This sequence of operations is then shared with whoever will decrypt the message. This is obviously insecure but i cannot put my finger on where to start breaking it. My main idea is a smart-brute-force where you try to read the cube after every operation and adapts your next operation accordingly. Would this be the best way to break it? What else could i do? I didnt find anythng in the sidebar saying that this kind of post is disallowed in this page but if it is please tell me and i will delete the post. EDIT: Added information that was missing. [link] [comments]  |
| Asylo: An open and flexible framework for enclave applications Posted: 04 May 2018 04:25 AM PDT |
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