how to convert from base64 to hexadecimal in php?

Question

I was thinking to use this:

<?php
$string1 = 'V2h5IEkgY2FuJ3QgZG8gdGhpcyEhISEh';
echo base64_decode($string1);
?>

The output for this example should always be 18 characters! But sometimes this output is less than 18.

24 (base64 characters) multiplied by 6 (bits per base64 character) equals to 144 (bits) divided by 8 (bits per ASCII character) equals to 18 ASCII characters.

The problem is that the output is displayed in plain text; and some characters don't even have a "text representation" and that data will be lost. The next test will show that there are 41 different ASCII characters with no visible output.

<?php
for ($i = 0; $i <= 255; $i++) {
    $string2 = chr($i);
    echo $i . " = " . $string2 . "<br>";
}
?>

My plan was to decode the base64 string and from the output in ASCII reconvert it to hexadecimal. Now that is not possible because of those 41 characters.

I also tried base_convert but there is no base64 support for it.

`bin2hex()` is a built-in function you might be interested in. — mario, Jun 06 '16 at 00:59
Possible duplicate of [Convert base64'd SHA1 hashes to Hex hashes](http://stackoverflow.com/questions/2914504/convert-base64d-sha1-hashes-to-hex-hashes) — zanderwar, Jun 06 '16 at 01:01
See http://stackoverflow.com/questions/2914504/convert-base64d-sha1-hashes-to-hex-hashes — zanderwar, Jun 06 '16 at 01:01

score 8 · Accepted Answer · answered Jun 06 '16 at 01:33

You can do this with bin2hex():

Returns an ASCII string containing the hexadecimal representation of str. The conversion is done byte-wise with the high-nibble first.

php > $string1 = 'V2h5IEkgY2FuJ3QgZG8gdGhpcyEhISEh';
php > echo base64_decode($string1);
Why I can't do this!!!!!
php > echo bin2hex(base64_decode($string1));
57687920492063616e277420646f20746869732121212121
php >

score 2 · Answer 2 · answered Jun 06 '16 at 01:34

2

<?php
$string1 = 'V2h5IEkgY2FuJ3QgZG8gdGhpcyEhISEh';
$binary = base64_decode($string1);
$hex = bin2hex($binary);
echo $hex;
?>

answered Jun 06 '16 at 01:34

cronos

536
2
8
20

score 1 · Answer 3 · answered Sep 27 '21 at 10:11

1

A simple one line solution is:

<?=bin2hex(base64_decode($string1));?>

answered Sep 27 '21 at 10:11

Omair Munir

135
8

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Sep 27 '21 at 10:43

how to convert from base64 to hexadecimal in php?

3 Answers3