PHP base64 encode and strict decode

<?php
function b64_encode(string $data): string
{
    return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
}

function b64_decode(string $text): string
{
    $padded = strtr($text, '-_', '+/');
    $padded .= str_repeat('=', (4 - strlen($padded) % 4) % 4);
    $decoded = base64_decode($padded, true);
    if ($decoded === false) {
        throw new InvalidArgumentException('Invalid base64 input');
    }
    return $decoded;
}