Question:

Public key Start?

Evelyn: 2 weeks ago

What does the public key address start at? and end? is that available? i was trying to see howmany public keys are available, and it would be cool to know at what number it starts and ends. the complete publickey with 04 bit on it

Answer:
Oliver: 2 weeks ago

Bitcoin public keys are simply points on the elliptic curve secp256k1. Each point has an x and y value, and an (uncompressed) public key is encoded with the 0x04 to show that it is an uncompressed public key as opposed to a compressed or other, and then followed by the x and y coordinates, each 32 bytes long. The 0x04 is just a prefix, the key itself is the point on the curve.

There are 2 interpretations of first and last keys that I can see. Either you mean the 'first' key is the one corresponding to a private key of 0x01, or the key with the smallest x and y values. secp256k1 is the curve y2 = x3 + 7, so any x and y values that satisfy this equation (modulo the prime p = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F [ref] (https://en.bitcoin.it/wiki/Secp256k1)) is a valid point on the curve and thus public key. So x=0, y=1 would not be a valid point, because it doesn't satisfy that equation.