LS47 Decrypt

Category: Ciphers

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

Input / output: string → string

Background: https://github.com/exaexa/ls47

What it does

This is a slight improvement of the ElsieFour cipher as described by Alan Kaminsky. We use 7x7 characters instead of original (barely fitting) 6x6, to be able to encrypt some structured information. We also describe a simple key-expansion algorithm, because remembering passwords is popular. Similar security considerations as with ElsieFour hold. The LS47 alphabet consists of following characters: _abcdefghijklmnopqrstuvwxyz.0123456789,-+*/:?!'() An LS47 key is a permutation of the alphabet that is then represented in a 7x7 grid used for the encryption or decryption.

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`	Password	`string`	`''`	`''`
`1`	Padding	`number`	`10`	A Python integer or floating-point value

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 = ['', 10]
result = bake(input_value, [{"op": 'LS47 Decrypt', "args": args}])
print(result)

Pipeline example

from pychef import Pipeline

args = ['', 10]
transform = Pipeline().then('LS47 Decrypt', *args)
result = transform("example")

Dedicated operation module

The registered entry point lives in pychef.operations.by_operation.ls47_decrypt. Direct calls receive the input value and a positional argument tuple:

from pychef.operations.by_operation.ls47_decrypt import run

result = run("example", tuple(['', 10]))

pychef.operations.by_operation.ls47_decrypt.run(value, args)

Run this operation using its shared internal implementation.

Parameters:

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

Return type:

str | bytes