LEA - the Lowery Encryption Algorithm

I pronounce it lay·uh (like Princess Leia), but pronounce it however you like, this isn't GNU. There are two main components to it, the ECHO hashing algorithm, and the BSC symmetric encryption algorithm. Both of these components are built and designed by me.

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ECHO - Expand Compact Hashing Order

ECHO uses two key steps in its hashing process: Bit Interleaving Expansion (BIE) and Sequential Bit Compaction (SBC). These work together to transform a password into a 256-bit keyhash with strong diffusion, ensuring similar inputs produce very different outputs.

Bit Interleaving Expansion (BIE)

What it does: Expands a 256-bit input into 512 bits by mixing original bits with transformed, input-derived bits.

How it works:

1. Split the input into 32 bytes (8 bits each). If input is shorter, loop over it.
2. For each byte (e.g., 01000001 for "A"):
   • Multiply its value by a prime (e.g., 17), take the 8-bit result (e.g., 01010001).
   • Flip those bits (e.g., 10101110).
3. Interleave: Place original bits (reversed) at even indices (0, 2, ...), transformed bits at odd indices (1, 3, ...).

Example:

• Input: 01000001.
• Byte: 01000001 → * 17 = 1105 (truncate bits after 8) → 01010001 → flip to 10101110.
• Interleave reversed input (10000010) with transformed byte (10101110): 1100010001011100.
• Output: 16 bits, half original, half scrambled.

Why: Doubles the data with chaos, making small changes (e.g., 0100 to 0101) spread wide.

Sequential Bit Compaction (SBC)

What it does: Compresses the 512-bit BIE output back to 256 bits while mixing bits further.

How it works:

1. Take the 512-bit input.
2. XOR each pair of adjacent bits (0 with 1, 2 with 3, etc.) to produce 256 output bits.

Example:

• Input: 01 00 11 01 (8 bits, imagine 512 total).
• XOR pairs: 0^1=1, 0^0=0, 1^1=0, 0^1=1.
• Output: 1001 (4 bits, scales to 256 in full).
• Full run: Each of 256 output bits combines an original and transformed bit.

Why: Folds the expanded data, ensuring every output bit reflects both input and its derived chaos.

Together

• BIE: Spreads 256 bits to 512 with interleaved transforms.
• SBC: Compacts 512 back to 256, mixing original and derived bits.
• Result: A 256-bit hash where tiny input changes (e.g., "abc" vs "abd") flip many output bits, proven by testing 10M+ hashes to ensure Collision Resistance and Avalanche Effect achievement.

More rounds and tweaks (rotation, flips) build on this core for extra strength.