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Questions tagged [ecb]

Electronic Code Book (ECB) is a mode of operation for a block cipher, with the characteristic that each possible block of plaintext has a defined corresponding ciphertext value and vice versa.

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Meet-in-the-middle attack (different block cipher modes)

Does a meet-in-the-middle attack on depend on the used modes for block ciphers? encryption: $C_i$ = $D_{K2}$($D_{K1}$($E_{K1}$($P_i$ $\oplus$ $C''_{i-1}$))) $\oplus$ $C'_{i-1}$ and $IV_1$ = $C''_0$ = ...
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Meet-in-the-middle attack (on custom encryption scheme)

This is a question I had from an exercise session. Exercise: First we do DES in CBC encryption mode using a key $K_1$ and $IV_1 = O^n$. Then we do DES in ECB decryption mode using $K_1$. And then DES ...
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Symmetric encryption construction (meet-in-the-middle attack)

This is a question I had from an exercise session. First we do DES in CBC encryption mode using a key $K_1$ and $IV_1 = O^n$. Then we do DES in ECB decryption mode using $K_1$. And then DES in CBC ...
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1answer
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LoRaWAN 1.0.2 Session Key Security

I am reading about LoRaWAN 1.0.2 specification. For the confidentiality and integrity of the comunication the protocol generate two session keys, the NwkSKey and the AppSKey (part 6.2.5 of the ...
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Can ECB be turned into a secure algorithm by adding obfuscation of the plaintext patterns?

Just to preface this I'm very new to cryptography. However, I've been reading that ECB should not be used under most circumstances due to its symmetry which allows attackers to gain information about ...
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What's the reason for Monte Carlo tests for block ciphers?

NIST specifies that implementations were required to create Monte Carlo test vectors for ECB and CBC mode for the AES competition. What's the reason for these tests? The only thing I can think of is ...
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In which cases AES doesn't need IV?

I was trying to decrypt a text encrypted with AES and ECB mode. I did try several key and IV. I solved it by ignoring IV. (The IV was given, but it was maybe a distractor) My question is in which ...
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250 views

Performing a dictionary attack on RSA/ECB with no padding

I have the exponent $e=2^{16}+1$ and modulus $n$ (154 digit number) of an RSA public key along with the ciphertext (64 bytes) encrypted using the same key with RSA/ECB and no padding. I am required ...
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1answer
333 views

Security of AES after key expansion 4-MB with ECB and CBC

My question is, how does the security depend or change if I encrypt with AES-128 in total 4-MB of Data? With Electronic Code Book Mode and Cipher Block Chaining Mode ? Does an adversary still ...
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Is it possible to find the key for AES ECB if I have a list of plaintext and corresponding ciphertext?

Assume I have a list of plaintext text and its corresponding ciphertext which was created using a specific key with AES in ECB mode. Can I recover that key? If, how big does the list of plaintext ...
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1answer
174 views

Encrypting AES in ECB mode

I'm fairly new to cryptography and am starting to understand this weird art of Mathematics and theory. One thing I am trying to understand and do is encrypting a plaintext into ciphertext using AES in ...
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194 views

Is AES ECB good enough for key spreading?

My apologies if I get my terminology wrong - I am new to this stuff. I am writing a routine (in c) to encrypt plaintext. I am using TinyAES to perform a CBC on the plaintext and sending a (pseudo)...
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3answers
218 views

Variation on the ECB Penguin problem [closed]

So this is an age-old example of why encrypting images with ECB is a terrible idea, since the underlying pattern of the image remains the same. Referenced from: If you encrypt an image (AES), is it ...
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205 views

With DES, is ECB encryption mode equivalent to CBC with null IV for short data blocks?

I got to this by experimentation, but can someone maybe provide an explanation for this?
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265 views

Which block cipher mode to use?

I am working on securing a chat application, and I am not sure about which block cipher mode I should use. I am aware that I should avoid ECB as it's insecure, but what about CBC? I have watched ...
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2answers
359 views

Security of AES ECB for 128 bit random data

I am using AES ECB mode to encrypt and decrypt 128 random data. I have read on drawbacks on using ECB but it seems that it is feasible to use it for random data. However my concern is that my ...
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1answer
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Can I work around these padding issue in AES 256 ECB due to Reed solomon encoding?

Disclaimer: I do NOT believe AES-ECB to be at all useful for encryption. That said, due to time and bureaucratic issues that I'm not in control of, I need to use AES-ECB. I get packets of data that ...
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Are there any benefits to using ECB over CBC?

From what I have understood about ECB and CBC, CBC is far better as it doesn't reveal any pattern. There have been several questions here about how ECB is bad: Should I use ECB or CBC encryption mode ...
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462 views

ciphertext stealing and CTR

Why Does CTR mode encryption not use ciphertext stealing?
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1answer
482 views

Why is Byte-at-a-time ECB decryption a vulnerability?

I've been working on the Cryptopals Cryptography challenge problems, and I recently solved one where you recover a plaintext given a encryption oracle. The oracle produces a ciphertext in ECB mode AES....
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1answer
463 views

Key recovery after AES-ECB encryption of two blocks with some known plaintext/ciphertext

I am analysing a small, bespoke end-to-end encryption service's source code, in particular their user registration process. I am finding some interesting things going on and I am wondering if there's ...
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How to cipher bocks with RSA in ECB mode?

I'm trying to implement a very basic RSA with functions that should generate RSA keys and cipher some text. GenKey function returns a tuple ...
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195 views

What if we increase the key length of DES and use ECB Mode, then will we get the different output as ECB mode encrypt with the same key?

I am looking for an answer as if we have DES having 64 bit key and we are encrypting an image it with ECB mode but it doesn't encrypt well. so if we change the key length then will it effect the ...
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1answer
503 views

Cryptopals challenge 2.11: Distinguish ECB and CBC encryption

I'm going through the Matasano crypto challenges (also known as cryptopals) and I recently got stuck in the following challenge: http://cryptopals.com/sets/2/challenges/11 The goal of the challenge ...
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1answer
433 views

Is AES in OFB mode with same IV more robust than ECB mode?

I am looking at implementing AES128 bit encryption of a data stream. Since AES128 is a block cipher, which is inherently less robust than a stream cipher, I have considered configuring AES128 as a ...
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1answer
3k views

AES-ECB known ciphertext/plaintext attack

i'm new to crypto and am working on a little exercise to understand the weakness of ECB mode encryption. Here is the scenario. I have the plain text ...
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1answer
1k views

Encrypting Keys in a Firmware-Update

I have a bootloader on a small device (Cortex-M0/M3). I want to publish encrypted firmware updates, that can be installed on the device, using the bootloader. The whole point of the encryption is to ...
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1answer
584 views

MySQL/MariaDB AES_ENCRYPT() - ECB mode, IV, Padding Oracle Attack Question

Multipart question all related to AES encryption with MariaDB. Strangely enough, it looks like even today MariaDB only has AES with ECB mode. MySQL allows CBC and more I believe. Anyway I'm stuck ...
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618 views

Manipulate encrypted file: AES / ECB / PKCS5Padding

As part of a competition I want to manipulate (or decrypt) a file. I know, that the file contains gzip compressed text and is encrypted with AES / ECB / PKCS5. I also have the plain text and the ...
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1answer
146 views

Is CBC still better than ECB if the key and a large part of the texts are random?

I am doing protection for my software, which involves storing a part of the crucial algorithm inside a smart-card based dongle. I will supply the input to the dongle, and I will expect the output of ...
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1answer
231 views

encode plaintext with ecb

I have a plaintext "DENKMAL" which I have to encode in the ECB mode with the block size = 1 character (whereby the assignment $A\leftrightarrow 0, B \leftrightarrow 1$, etc.) Now I should find the ...
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523 views

Why are ECB CBC and CFB parallelizable?

I guess I do not understand the word 'parallelizable'. Why are ECB CBC and CFB parallelizable? It would be nice if someone could explain it in a short way.
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ECB attack to bank transfer

I have a problem with a task from my university. We have two banks and these banks are sending data in ECB mode. Plaintext and ciphertext look like this: Plaintext: ...
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2answers
626 views

ECB vs CBC for encrypting high entropy data

I have a master AES key and I need to encrypt other AES keys with this key. Is ECB safe to encrypt highly random data (a key)? What benefit would I get if I use CBC instead? In particular, are the ...
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How does GnuPG compress a file and how to deal with it? [closed]

When encrypting a file symmetrically with gpg -c file.txt, when and how does it compress the file? I was working on a cryptopals challenge and wanted to test out ...
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Implement AES-CTR on top of AES-ECB

I using a microcontroller which only support AES-ECB encryption i.e. no decryption-mode, CBC, GCM or similar modes. However, I'm wondering if it's possible to implement AES-CTR or similar on top of ...
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457 views

Attack mode for DES + ECB

Given that the plain text(P) and the ciphertext is known, and there's a random string(8 bytes)(S) concatenated to the plain text(P || S), how to go about figuring out the random string. Querying of ...
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1answer
190 views

64 bits cipher and birthday boundaries in ECB

I am using a 64 bits symmetric ciphers (blowfish), to encrypt a plain block using ECB. The plaintext is always 64 bits long, but due to some limitations I have to use the same key (448 bits long) ...
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1answer
931 views

AES-256-ECB to encrypt VOIP audio-stream?

I need to encrypt a live audio-stream that is being sent over the internet. The details are: The stream contains spoken language (VOIP) Only the raw stream is transmitted (no meta-data or container) ...
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2answers
162 views

Can you tell if this ECB mode mitigation idea is “OK”?

The context: you have to encrypt passwords (reversible, for accessing external services), and also some customer data for privacy reasons, and you need to use AES-ECB mode... The idea to mitigate the ...
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Chosen Plaintext attack on AES in ECB mode

I am familiar with the following method for an chosen-plaintext injection attack on ECB ciphers, where I am allowed to append a block of bytes to the packet being encrypted: I inject a string with ...
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1answer
968 views

ECB vs. CBC, I've seen the pictures, but what's the actual strength difference?

I hope that this is not a duplicate because I'm looking for nuance. I understand the difference between ECB and CBC for a block cipher, and I understand that ECB is susceptible to replay attacks, but ...
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4answers
362 views

Using a block cipher with timestamp instead of counter

I have a system where machine A sends updates to machine B. The updates are sent over the internet, where each update is a single UDP datagram. Machine A sends a local timestamp in each update (we can ...
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1answer
196 views

Using rainbow tables to find encryption keys of block ciphers?

Hi I have a question in mind. Let's consider a block cipher whose key length is 36 bits. The bit-length of the plaintext is 256 bits, but there are only 16 possible plaintexts $m_0, m_1, . . . , ...
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2answers
2k views

Is it possible to break AES-128 ECB if you are given a ciphertext and a small portion of the key?

If you are given the ciphertext and the first half bytes (8 bytes) of the encryption key (key is 16 bytes in total), can you use this to break AES-128 ECB encryption and determine the last 8 bytes of ...
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How can I find or reverse engineer the whitening in an AES algorithm?

I am working with this black box cryptography scheme. I know the plain text, cipher text, and everything else except how they whiten the data (or key?). Everything is 128 bit, 16 bytes. I have two ...
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2answers
293 views

Is it feasable to combine ECB and CTR block modes of operation?

Both ECB and CTR block modes have advantages over other block modes. They both support parallel encryption and decryption and random reads/writes. Yet both have major disadvantages: (I'm assuming AES ...
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AES ECB one more experiment

I checked the most common AES modes and I think I got the goal of them: avoid same cyper text for same plain text. However all modes except ECB have the weakness that lost part of the message stream ...
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1answer
490 views

How can I break this block-cipher?

So we've got to do this assignment for our study, but we can't figure out what to do, can someone help? Assume that Alice and Bob want to communicate via encrypted email. To this end, they first meet ...
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2answers
912 views

Key recovery when AES ECB is used for short but repeated messages

My question is based on the specification of the protocol LoRaWAN and especially on the part 6.2.5 Join-accept message. It is said that the join-accept message is encrypted using AES ECB. This is (...