Hawkynt

RC4-drop[65536] (DarkCrypt)

Standard RC4 KSA/PRGA with a fixed 1024-bit (128-byte) key, discarding the first 65536 generated keystream bytes before output. As implemented in the DarkCrypt Total Commander plugin (readme entry “RC4-drop[65536] (1024 bit)”).

Properties

Property	Value
Category	Stream Ciphers
Sub-category	Stream Cipher
Security status	❌ Broken
Complexity	Beginner
Inventor	Ron Rivest (RC4); DarkCrypt build by Alexander Myasnikov
Year	1987
Origin	🇷🇺 Russia
Source	algorithms/stream/darkcrypt-rc4drop.js

Parameters

Parameter	Supported values
Key sizes	128 bytes (1024 bits)
Nonce sizes	0 bytes (0 bits)

Security

Status: ❌ Broken

Known vulnerabilities

Issue	Description	Mitigation
Statistical Biases	Dropping the first 65536 bytes mitigates but does not eliminate known RC4 keystream biases	DO NOT USE - Use ChaCha20 or AES-GCM instead

Documentation

• RFC 6229: Test Vectors for RC4
• DarkCrypt plugin (Total Commander PlugRing)

Test vectors

2 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — DarkCrypt Rc4drop — incrementing 128-byte key, 128-byte zero keystream after drop

Field	Value
key	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f 404142434445464748494a4b4c4d4e4f 505152535455565758595a5b5c5d5e5f 606162636465666768696a6b6c6d6e6f 707172737475767778797a7b7c7d7e7f
input	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
expected	d4bb07e3632f1774c816557a74378899 c56bbd2cb76ddd7034c2a15112648524 66314c6b086c59efc926c365d5a778c8 205c27e38386fd45c79cf68ea75681c6 fc8dd9d55726703aa314f76f9c91ba58 3d0875c0fbc7f29c10555aa5b8d312e1 9ba17baf096aa0f982d578774222bbe5 dd363d48454a8f9dce2984ade642e40f

Vector 2 — DarkCrypt Rc4drop — incrementing 128-byte key/plaintext

Field	Value
key	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f 404142434445464748494a4b4c4d4e4f 505152535455565758595a5b5c5d5e5f 606162636465666768696a6b6c6d6e6f 707172737475767778797a7b7c7d7e7f
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
expected	d4ba05e0672a1173c01f5f71783a8696 d57aaf3fa378cb672cdbbb4a0e799b3b 46106e482c497fc8e10fe94ef98a56e7 106d15d0b7b3cb72ffa5ccb59b6bbff9

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