Questions tagged [chacha]
ChaCha is a family of stream ciphers proposed by Daniel J. Bernstein, as an evolution of Salsa20 with (conjecturally) improved resistance to cryptanalysis.
179
questions
7
votes
2
answers
780
views
Fast cipher without needing hardware support (like ChaCha20) for disk encryption
On my old laptop, ChaCha20 is quite a bit faster than AES as there is no hardware acceleration for AES. But for disk encryption AES based schemes seem to be the only option, as a stream cipher like ...
- 233
7
votes
3
answers
3k
views
Is it safe to use a random numbers instead of a counter in ChaCha20?
Besides the IV, ChaCha20 takes a random number and a counter as input.
I couldn't find more precise information about this but it seems to be that the counter is just a safety measure in case of a ...
- 229
2
votes
2
answers
109
views
Can you use ChaCha20 as one-time pad?
My knowledge of cryptography nothing beyond basic so I am by no means an expert, but I do know a bit of undergraduate mathematics including number theory.
I know that stream ciphers like ChaCha20 is ...
- 93.4k
0
votes
0
answers
49
views
ChaCha20 1Gb encryption speed question
I wrote a simple implementation of ChaCha20 encryptor for files in C using MbedTLS implementation. The process of encryption is standard - I set key, then for each block of fixed size I generate new ...
- 1
1
vote
1
answer
340
views
ChaCha20 as a block cipher
Would it be possible to use ChaCha20 as a block cipher? With the key, the entire block function can be reversed.
- 143k
1
vote
2
answers
156
views
Constant values of ChaCha20
Is it possible to change the constant values of ChaCha20?
and how it will affect the security of the cipher.
- 298
1
vote
0
answers
72
views
Extended-Chacha20
Research paper: "Extended-Chacha20 Stream Cipher With
Enhanced Quarter Round Function"
The initial matrix is 6x6, but what are the exact inputs for each index, in other words, how will you ...
- 233
1
vote
2
answers
316
views
Hamming Distance and Avalanche effect in Cryptography?
I am new to Cryptography and I know there are better ways to test a cipher's effectiveness out there but in this case I am trying to test a cryptographic algorithm's(AES,xchacha20,twofish) hamming ...
- 1,102
3
votes
1
answer
485
views
Is there any way to measure entropy of encryption algorithms in python?
I am new to cryptography and I am trying to find a way to measure ciphertext entropy of encryption algorithms such as AES, Chacha20, etc for a school project. Is there any way to do it on Python? I ...
- 93.4k
2
votes
1
answer
244
views
Why doesn't ChaCha use a 512bit key and xor parameters into it?
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX-like ($k=0$) approach such that the ChaCha key is 512 bits and all the other things are ...
- 1,659
2
votes
1
answer
199
views
48-bit nonce reuse with ChaCha20
The situation:
I have a group with 20 members, each member broadcasting 1 message per second. Communicating one on one is possible, but 1 message per member per second is the absolute limit and every ...
- 43
0
votes
1
answer
161
views
Chacha20 key/nonce/counter correct usage
Setting all 48 ChaCha state bytes (key, nonce, initial counter) from one result of strong hash function like sha3-384 or blake2b - correct usage? or bad practice?
PS: using original chacha20 (8bytes ...
0
votes
1
answer
361
views
ChaCha20-Poly1305 and AES-GCM-SIV output size
Background information:
I need to encrypt 168bit messages, the ciphertext should, preferably, match the plaintext size. Message Authentication and Integrity is not a must, but a really important ...
- 49.1k
63
votes
5
answers
101k
views
What's the appeal of using ChaCha20 instead of AES?
I read about ChaCha20 being used in TLS by Google, SSH, and towards standardization in general.
What's the appeal of using something other than AES, what with AES receiving dedicated CPU instructions ...
- 101
2
votes
1
answer
139
views
Recommended output filter for Rumba20 [closed]
Rumba20 is a compression function that maps a 192-byte (1536-bit) string to a 64-byte (512-bit) string. It's designed to provide collision resistance by using Salsa20 (or ChaCha20) with the ...
- 1,833