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arc4

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library0.5.0pypypi✓ verified 84d ago

A small and insanely fast ARCFOUR (RC4) cipher implementation of Python. Version 0.5.0. Maintenance releases as needed.

security

pip install arc4

github ↗homepage ↗

INSTALL

IMPORT

SIG · ARC4

arc4

securitypythonv0.5.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

ARC4

✓ from arc4 import ARC4

✗ import arc4

arc4 is a module, not the class. Use 'from arc4 import ARC4'.

Encrypt and decrypt bytes with ARC4. Must re-initialize ARC4 for decryption to reset the state.

from arc4 import ARC4 key = b'secret' arc4 = ARC4(key) ciphertext = arc4.encrypt(b'plaintext') print(ciphertext.hex()) arc4 = ARC4(key) plaintext = arc4.decrypt(ciphertext) print(plaintext.decode())

Debug

Known issues

gotchaARC4 is a stream cipher; the same key must be reinitialized for decryption (state is mutated).

fix

Create a new ARC4 instance with the same key before decrypting.

affects: all

gotchaARC4 is considered broken; do not use for new encryption. Use modern ciphers like AES.

fix

Use cryptography library's AES-GCM instead.

affects: all

Errors

Common errors & fixes

AttributeError: module 'arc4' has no attribute 'ARC4'

Using 'import arc4' and then 'arc4.ARC4'.

fix

Use 'from arc4 import ARC4'.

TypeError: key must be a bytes-like object

Passing a string instead of bytes for key or data.

fix

Encode strings: b'mykey' or 'mykey'.encode()

Upgrade

Version history

0.5.0latest on PyPI · released Apr 5, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

45 hits · last 30 days

node

Resources

githubhttps://github.com/manicmaniac/arc4 ↗

homepagehttps://github.com/manicmaniac/arc4 ↗