All Questions
Tagged with chacha stream-cipher
43
questions
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.
- 21
1
vote
0
answers
72
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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 ...
- 21
3
votes
2
answers
1k
views
Encrypting arbitrary large files in AEAD chunks - how to protect against chunk reordering?
I would like to encrypt big files using an authenticated cipher. I am convinced to use approach where file is divided into smaller manageable chunks that fit easily in memory (e.g. 1-10MB size) which ...
- 133
1
vote
1
answer
330
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Age: stream cipher with public key cryptography?
I have some rudimentary cryptography knowledge but am by no means an expert.
I generally understand stream ciphers, such as such as ChaCha20-Poly1305, to be symmetric. I am wondering how age (https://...
0
votes
1
answer
140
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Various attacks on cipher-images & tools, especially stream-cipher?
What kind of attack of image encryption that exist out there, especially if the cipherimage was created using secure stream-cipher like Salsa20 (256 key) or ChaCha20 (256 key)?
From https://cr.yp.to/...
- 87
4
votes
0
answers
153
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Why Block Ciphers
I fail to understand what block ciphers can do that stream ciphers cannot.
Also aren't they construct able from one another.
prg(stream cipher) -> prf -> prp(block cipher)
Any practical example ...
- 41
0
votes
1
answer
236
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What is the lightest cipher that provides AES like security?
The lightest, or fastest cipher, that is well known and quite secure like AES. Is ChaCha20 a good option? Are there any better alternatives that are faster but still as secure?
- 25
2
votes
1
answer
5k
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XChaCha20 vs AES 128 security and speed
Is XChaCha20 with 256 bit key and 192 bit nonce more secure than 128 bit key 128 bit key nonce AES, due to using larger key/nonce sizes? Isn't it supposed to be faster due to being a stream cipher? (...
- 25
0
votes
0
answers
57
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Applicability of theoretical attack procedure in actual attack to ChaCha cipher
I was studying the theoretical attacks on ChaCha cipher here (See section 3).
There is one special attack procedure which require key-IV(Initial Vector) pairs. These key-IV pairs are special in the ...
- 145
1
vote
0
answers
248
views
xChaCha20 Block Keys for Poly1305
So xChaCha20 has a nonce size large enough to safely use a random nonce with the same key. Poly1305 generally uses the first block of the cipher's output to generate its nonce. For xChaCha20 it would ...
- 123
0
votes
1
answer
3k
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How to choose between AES256-GCM, XSalsa20Poly1305 and XChaCha20Poly1305?
In libsodium, there're 3 symmetric encryption(stream cipher) which are AES256-GCM(Hardware-accelerated), XSalsa20Poly1305 and XChaCha20Poly1305(uncertain which version of libsodium add support to ...
- 159
1
vote
0
answers
255
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What is the best way to save ChaCha20 Nonce in Cipher-Image BMP file?
I have a question about ChaCha20. As far as I know ChaCha20 is a cipher algorithm that uses 4 inputs:
Key (secret)
Constant (not secret)
Block Number/Counter (keystream block number)
Nonce (random ...
- 87
0
votes
1
answer
207
views
Where can I find test vectors for ChaCha20 (trying to understand Wikipedia example)?
I was playing around with stream ciphers an found this Wikipedia ChaCha20 page (the ChaCha variant). What I'm lost with is how to test this code. There are no testvectors anywhere on that page and I ...
3
votes
1
answer
2k
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It possible to encrypt .bmp bitmap files using Stream Cipher Chacha20?
Maybe this sounds like a stupid question. I'm sorry for that.
I just wanted to know is it possible to encrypt a bitmap image file like *.BMP, and generate the ciphertext which is an obscure bitmap ...
- 87
2
votes
3
answers
465
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Benchmark for CSPRNG as stream ciphers?
My limitation in my security protocol is that I want my RNG as CSPRNG and I also want it to be super fast.
If I use Salsa20 or ChaCha or AES counter mode, I don't get the desired speed. I want my PRNG ...
- 39