Compiletime string constant obfuscation for Rust.
The string constant itself is embedded in obfuscated form and deobfuscated locally. This reference to a temporary value must be used in the same statement it was generated. See the documentation for more advanced use cases.
Looking for obfuscating formatting strings? See fmtools (github, crates.io, docs.rs) with the optional dependency obfuscate enabled to automatically apply string obfuscation to formatting strings.
The obfstr! macro returns the deobfuscated string as a temporary value:
use obfuscate::obfuscate as s;
assert_eq!(s!("Hello 🌍"), "Hello 🌍");The wide! macro provides compiletime utf16 string constants:
let expected = &['W' as u16, 'i' as u16, 'd' as u16, 'e' as u16, 0];
assert_eq!(obfuscate::wide!("Wide\0"), expected);The random! macro provides compiletime random values:
const RND: i32 = obfuscate::random!(u8) as i32;
assert!(RND >= 0 && RND <= 255);Compiletime random values are based on file!(), line!(), column!() and a fixed seed to ensure reproducibility.
This fixed seed is stored as text in the environment variable OBFSTR_SEED and can be changed as desired.
The djb2 hashing algorithm (k=33) was first reported by Dan Bernstein many years ago in comp.lang.c. Another version of this algorithm (now favored by Bernstein) uses xor:
hash(i) = hash(i - 1) * 33 ^ str[i];The magic of number 33 (why it works better than many other constants, prime or not) has never been adequately explained.
Licensed under MIT License, see license.txt.
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