Encode 256 bytes and 10 bytes

functions.php

<?php
function b256_to_b10_encode( $string, $encoding = "UTF-8" ) {
    bcscale( 0 );

    $result = "0";

    for ($i = mb_strlen( $string, $encoding )-1; $i >= 0; $i--) {
        $result = bcadd( $result, bcmul( ord( $string[$i] ), bcpow( 256, $i ) ) );
    }

    return $result;
}
function b10_to_b256_encode( $string ) {
    bcscale(0);

    $result = "";
    $n = $string;

    do {
        $remainder = bcmod( $n, 256 );
        $n = bcdiv( $n, 256 );
        $result .= chr( $remainder );
    } while ($n > 0);

    return $result;
}