Linked Questions

19 votes
4 answers
6k views

Is SHA-256 secure as a CTR block cipher?

Generate a 256-bit random nonce. XOR it with a 256-bit reusable symmetric key. This is x. We represent numbers in simple binary instead of a counting function. <...
Jordan's user avatar
  • 585
6 votes
1 answer
32k views

Is regular CTR mode vulnerable to any attacks?

Regular plain CTR mode, is it vulnerable to any attack? I plan to write a program to encrypt a drive with ctr mode. Would this be wise? Would AES be better? When I look at this diagram, it looks ...
tuang's user avatar
  • 63
18 votes
1 answer
32k views

Bit Flipping Attack on CBC Mode

To perform a bit flipping attack, the previous block is modified by using XOR. This results in an altered plaintext. However, now the ciphertext of the previous block is altered, hence it will result ...
CXB's user avatar
  • 321
12 votes
3 answers
3k views

Using a Non-Random IV with modes other than CBC

The weakness CWE-329 is an interesting problem with CBC mode. However, does this same weakness affect the other modes of operation that rely upon an IV such as: PCBC, CFB and OFB? My gut feeling is, ...
Rook's user avatar
  • 1,506
3 votes
3 answers
5k views

Is CTR more secure than CBC?

In cryptography, a block cipher mode of operation is an algorithm that uses a block cipher to provide information security such as confidentiality or authenticity. A block cipher by itself is only ...
moyu's user avatar
  • 73
16 votes
1 answer
8k views

What are the rules for using AES-GCM correctly?

When using AES-GCM I know that I am supposed to use a new initialization vector every time I call the AES-GCM algorithm with the same key. What are other rules must be followed to use AES-GCM ...
ams's user avatar
  • 671
2 votes
2 answers
5k views

What is the difference between pseudorandom permutation/pseudorandom function/block cipher?

What is the difference between; pseudorandom permutation pseudorandom function block cipher? Very confused with the 3 terms and I am not good at advanced math. Can someone explain in plain word?
Mark's user avatar
  • 21
1 vote
2 answers
1k views

How insecure would a cipher based on iterative hashing be?

I was just wondering how the following construction could be insecure. I can tell that known-plain attacks are possible, but I'm not sure about anything else. Let the user pick a password and hash it ...
Li Gang's user avatar
  • 19
4 votes
2 answers
4k views

Proper use of AES CTR

I've read that AES CTR is only safe if used properly. Therefore, I want to be sure that I use it properly. The initial vector (IV) can only be used once, it doesn't have to be random. Is it secure to ...
SOSO30's user avatar
  • 43
2 votes
2 answers
599 views

Does keeping IV secret increase security of CTR mode?

Let's suppose I encrypt something with CTR mode and keep the key and IV secret. Does keeping the IV secret together with the key increase strength of encryption?
phantomcraft's user avatar
5 votes
1 answer
316 views

Stream Cipher Key Stream from Successive Hashes

I'm currently studying crypto and wondered what would be wrong with the following process... I want to encrypt a long message $M$ with a short symmetric key $K$ and a public nonce $X$. The idea is to ...
Contaso's user avatar
  • 53
0 votes
2 answers
1k views

Encryption algorithm multiple threads/cores for higher throughput

There are situations where a single connection (or file) may require additional throughput available. While network bandwidth and CPU cores are available, they cannot be utilised. (Aside from means ...
Kind Contributor's user avatar
1 vote
2 answers
635 views

Why is possible to encrypt multiple messages within the same stream in AES

I have a standard random key and IV. Then I am creating a cipher using these keys and iv and then encrypt a specific message. Later on, if I try to encrypt another message with the same cipher(which ...
user avatar
4 votes
2 answers
635 views

What input parameters can be made public in the AES-CTR mode?

Preface: I am beginner of cryptography and not native English speaker. So I may make terrible mistake (about grammar and cryptography). I understand that the parameters used for AES-CTR are "key&...
kaki's user avatar
  • 41
3 votes
1 answer
1k views

What is the maximum number of messages that can be encrypted using the same key for CTR mode?

In the counter mode of encryption, the nonce cannot be used again unless a new block cipher key is chosen. What is the maximum number of messages that can be encrypted using the same key? The maximum ...
geektobe's user avatar

15 30 50 per page