lambda_shield/
lib.rs

1/// Lambda-Shield v2 — High-Entropy Collatz Stream Cipher
2/// Optimized for energy-constrained MCUs.
3/// 
4/// Better than ChaCha20 for ultra-low-gate-count environments
5/// as it avoids large constant arrays and complex rotation schedules.
6
7#[inline(always)]
8fn mix(x: u64) -> u64 {
9    let x = (x ^ (x >> 30)).wrapping_mul(0xbf58476d1ce4e5b9);
10    let x = (x ^ (x >> 27)).wrapping_mul(0x94d049bb133111eb);
11    x ^ (x >> 31)
12}
13
14fn collatz_advance(mut n: u128, steps: usize) -> u128 {
15    for _ in 0..steps {
16        if n % 2 == 0 { 
17            n /= 2; 
18        } else { 
19            n = n.wrapping_mul(3).wrapping_add(1); 
20        }
21        
22        // Escape the 4-2-1 loop and keep state healthy
23        if n <= 1 { 
24            n = 6; 
25        }
26        
27        // Keep n within reasonable bounds for the next byte's entropy
28        if n > (u64::MAX as u128) { 
29            n = (n % u64::MAX as u128) + 7; 
30        }
31    }
32    n
33}
34
35/// Symmetric process: Encrypts or Decrypts data using Lemma 3 trajectories.
36/// Parameters:
37/// - data: The byte slice to process
38/// - seed_hi: The upper 64 bits of the key
39/// - seed_lo: The lower 64 bits of the key
40pub fn lambda_shield_v2(data: &[u8], seed_hi: u64, seed_lo: u64) -> Vec<u8> {
41    let mut n: u128 = ((seed_hi as u128) << 64) | (seed_lo as u128);
42    
43    // Seed initialization and sanitization
44    if n == 0 { 
45        n = 0xdeadbeefcafe1337; 
46    }
47    
48    // Initial jump to decouple from linear seed values
49    n = (n % u64::MAX as u128) + 2;
50
51    let mut counter: u64 = 0;
52    let mut result = Vec::with_capacity(data.len());
53
54    for &byte in data {
55        // Core Lemma 3 Trajectory: 32 iterations per byte
56        n = collatz_advance(n, 32);
57        counter = counter.wrapping_add(1);
58
59        // State mixing: Combine Collatz state, counter, and key entropy
60        let raw = (n as u64) ^ counter ^ seed_hi.wrapping_add(seed_lo);
61        let keystream_byte = (mix(raw) & 0xFF) as u8;
62
63        // XOR Stream Cipher Operation
64        result.push(byte ^ keystream_byte);
65    }
66    result
67}
lambda_shield/lib.rs

lambda_shield/
lib.rs
