rc4-plaintext

Rust program to bruteforce rc4 hidden key given a known key mask to produce a known keystream.

Build

run the following command from the root directory:

cargo build --release

Run

To run the program execute the following in the root directory:

./target/release/rc4_pt_attack "{known_key_mask}" "{target_plaintext}" {start_from_0: bool} {drop_n} {number_of_thread}

CLI Arguments

1. known_key_mask - hex string with ?? as unknown bits - (?s must be on character boundaries)
2. target_plaintext - hex string of ct xor pt
3. start_from_0 - true => start from 0 and work up; false => start from 255 and work down to find key
4. (Optional) drop_n - the number of bytes to drop before generating a keystream (defaults to 0)
5. (Optional) number_of_threads - the number of threads in the threadpool to conduct calculations (defaults to 1)

Examples

To run a plaintext attack against a 72-bit key of 0x37415869??06??9D?? with a drop_n of 256 bytes and a desired keystream of 0x582B4552EBD97C run the following:

./target/release/rc4_pt_attack "0x37415869??06??9D??" "0x582B4552EBD97C" true

To run a plaintext attack against a 104-bit key of 0x??????????5560F28DC480C689 with a drop_n of 256 bytes and a desired keystream of 0xD88125F83E6962 starting from 255 and working down using 32 threads

./target/release/rc4_pt_attack "0x??????????5560F28DC480C689" "0xD88125F83E6962" false 256 32

To run a plaintext attack against a 104-bit key of 0x??76??32??78AD2D347D16??CC with a drop_n of 267 bytes and a desired keystream of 0xC5C593CB6AC6F419A3441A starting from 255 and working down using 16 threads

./target/release/rc4_pt_attack "0x??76??32??78AD2D347D16??CC" "0xC5C593CB6AC6F419A3441A" false 267 16