What are common mistakes when using base64_decode in PHP?

Common mistakes when using base64_decode in PHP include not checking the return value of the function, assuming that base64_decode will always return the decoded string, and not handling errors properly. To solve this, always check the return value of base64_decode to ensure it was successful, and handle any errors that may occur during decoding.

$encoded_string = "VGhpcyBpcyBhIGJhc2U2NCBlbmNvZGVkIHN0cmluZw==";
$decoded_string = base64_decode($encoded_string);

if ($decoded_string === false) {
    // Handle decoding error
    echo "Error decoding base64 string";
} else {
    // Use the decoded string
    echo $decoded_string;
}