How can all possible numbers in 256-bit space be squeezed into 160-bit space? Bitcoin addresses are essentially 160-bit hashes of a 256-bit public key. Huh? How can all possible numbers in 256-bit space be squeezed into 160-bit space? Does that mean any given bitcoin address could be derived from more than just one public key?
It's really 160 bit hash (RIPEMD160) of an already hashed (SHA256) public secp256k1 elliptic curve key. And yes, on the average, every address has about 2256-160=296 pairs of private/public keys.