"1) Taking longer is not an indication of strength of the algorithm. Just like banging your head into a wall, multiple times isn't the best way to pass through

"1) Taking longer is not an indication of strength of the algorithm. Just like banging your head into a wall, multiple times isn't the best way to pass through it." You do realize that this is how all modern "cryptographically secure" hash functions work, right? For that matter, so do the symmetric-key block ciphers that hashes are closely related to. All of them simply use S-boxes to obfuscate the numbers, followed by repeated "rounds" of simple bitwise primitives (bitshift, and, xor, perhaps addition modulo a power of 2). There's no inherent mathematical reason why combinations of these simple functions should be strong, when each function individually is weak. This is precisely why cryptography is such a tricky field to work in.