/**
* Encode
*
* This function accepts an array of information describing the
* extended key. It will determine the magic bytes depending on the
* network, testnet, and type indexes. The fingerprint is accepted
* as-is, because the CKD() and master_key() functions work that out
* themselves. The child number is fixed at '00000000'. Private key's
* are padded with \x00 to ensure they are 33 bytes. This information
* is concatenated and converted to base58check encoding.
* The input array has the same indexes as the output from the import()
* function to ensure compatibility.
*
* @param array $data
* @return string
*/
public static function encode($data)
{
// Magic Byte - 4 bytes / 8 characters - left out for now
$magic_byte_var = strtolower($data['network']) . "_" . ($data['testnet'] == TRUE ? 'testnet' : 'mainnet') . "_{$data['type']}";
$magic_byte = self::${$magic_byte_var};
$fingerprint = $data['fingerprint'];
$child_number = $data['i'];
$depth = str_pad(gmp_strval(gmp_init($data['depth'], 10), 16), 2, '0', STR_PAD_LEFT);
$chain_code = $data['chain_code'];
$key_data = $data['type'] == 'public' ? $data['key'] : '00' . $data['key'];
$string = $magic_byte . $depth . $fingerprint . $child_number . $chain_code . $key_data;
return BitcoinLib::base58_encode_checksum($string);
}
