ChaCha

Category: Ciphers

Status: Registered and callable in the CyberChef 11.3.0 compatibility inventory.

Input / output: string → string

Background: https://wikipedia.org/wiki/Salsa20#ChaCha_variant

What it does

ChaCha is a stream cipher designed by Daniel J. Bernstein. It is a variant of the Salsa stream cipher. Several parameterizations exist; ‘ChaCha’ may refer to the original construction, or to the variant as described in RFC-8439. ChaCha is often used with Poly1305, in the ChaCha20-Poly1305 AEAD construction. Key: ChaCha uses a key of 16 or 32 bytes (128 or 256 bits). Nonce: ChaCha uses a nonce of 8 or 12 bytes (64 or 96 bits). Counter: ChaCha uses a counter of 4 or 8 bytes (32 or 64 bits); together, the nonce and counter must add up to 16 bytes. The counter starts at zero at the start of the keystream, and is incremented at every 64 bytes.

Note

Status here means the operation name is implemented and callable. It does not by itself promise byte-for-byte parity for every upstream option. See Compatibility and current status for the verified scope and known boundaries.

Arguments and options

Arguments are positional. Keep their order when using bake() or Pipeline.then().

Index	Name	UI type	PyChef default	Accepted values / format
`0`	Key	`toggleString`	`{'string': '', 'option': 'Hex'}`	`''`
`1`	Nonce	`toggleString`	`{'string': '', 'option': 'Hex'}`	`''`
`2`	Counter	`number`	`0`	A Python integer or floating-point value
`3`	Rounds	`option`	`'20'`	`'20'`, `'12'`, `'8'`
`4`	Input	`option`	`'Hex'`	`'Hex'`, `'Raw'`
`5`	Output	`option`	`'Raw'`	`'Raw'`, `'Hex'`

Recipe template

Important

This is a call template built from the documented defaults. Replace placeholder values such as empty keys, paths, patterns, or lookup data before running it.

from pychef import bake

input_value = "example"
args = [{'string': '', 'option': 'Hex'}, {'string': '', 'option': 'Hex'}, 0, '20', 'Hex', 'Raw']
result = bake(input_value, [{"op": 'ChaCha', "args": args}])
print(result)

Pipeline example

from pychef import Pipeline

args = [{'string': '', 'option': 'Hex'}, {'string': '', 'option': 'Hex'}, 0, '20', 'Hex', 'Raw']
transform = Pipeline().then('ChaCha', *args)
result = transform("example")

Dedicated operation module

The registered entry point lives in pychef.operations.by_operation.chacha. Direct calls receive the input value and a positional argument tuple:

from pychef.operations.by_operation.chacha import run

result = run("example", tuple([{'string': '', 'option': 'Hex'}, {'string': '', 'option': 'Hex'}, 0, '20', 'Hex', 'Raw']))

pychef.operations.by_operation.chacha.run(value, args)

Run this operation using its shared internal implementation.

Parameters:

value (str | bytes)
args (Sequence[Any])

Return type:

str | bytes