pubkeybitcoin - calculate a secp256k1 public key from a private key. Secp256k1 is used in Bitcoin.
Examples:
sh pubkeybitcoin.sh -f hex FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364140
sh pubkeybitcoin.sh -f wif L5oLkpV3aqBjhki6LmvChTCV6odsp4SXM6FfU2Gppt5kFLaHLuZ9
Output: 0379BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798.
