Why var_dump return true with different comparison of md5 hash?

Question

I wonder why this code return true instead of false

var_dump(md5('240610708') == md5('QNKCDZO'));

Thanks in advance, any explanation will be appreciated.

The second answer on [this question](http://stackoverflow.com/questions/3333353/string-comparison-using-vs-strcmp) may be helpful for you. — TheGentleman, Apr 08 '17 at 15:53

score 1 · Answer 1 · answered Apr 08 '17 at 15:48

1

Try this instead:

var_dump(md5('240610708') === md5('QNKCDZO'));

answered Apr 08 '17 at 15:48

Sloan Thrasher

4,953
3
22
40

Is it verified? – Siraj Alam Apr 08 '17 at 15:50
Yes, I tested it with your values, and again using the same value for both MD5 expressions. – Sloan Thrasher Apr 08 '17 at 15:53

ghostprgmr · Answer 2 · 2017-04-08T15:57:21.417

1

Looks, like these md5 hashes, which starts from '0e', are parsed by PHP as a decimal numbers with exponent (see var_dump(100 == "1e2"); // 100 == 100 -> true from Comparison Operators).

That is why they are interpreted as equals. To avoid this, must use strict comparison.

Update:

And strcmp gives the correct result, too. If I understand correctly, because there is no conversions in case of strcmp.

edited Apr 08 '17 at 15:57

answered Apr 08 '17 at 15:51

ghostprgmr

488
2
11

1

You can also use `strcmp()` – TheGentleman Apr 08 '17 at 15:52

Why var_dump return true with different comparison of md5 hash?

2 Answers2