Ruby PHP MD5 Incompatible - How is this possible?

Question

How is this possible? I can't get Ruby to give me the same MD5 as PHP does and can't figure this out... I thought encoding, but it seems I've managed to keep every file in the same format.

PHP Code: (result: bfa7df865d9f4aff62c4643d0e1cb33b)

echo md5("9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@#@akskd9");

Ruby Code with Digest-MD5: (result: bd53907a1b47e9a381ee663ec75b59f4)

require 'digest/md5'
puts Digest::MD5.hexdigest("9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@#@akskd9")

Ruby Code with HMAC-MD5: (result: d41d8cd98f00b204e9800998ecf8427e)

require 'hmac-md5'
puts HMAC::MD5.new("9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@#@akskd9").hexdigest

A newline character after the ! might have something to do with it — Mark Baker, Feb 15 '13 at 17:53
Mark, is that a control sequence I'm not aware of? Because I don't have a newline character in there at all ... unless it's through a control sequence like \n or something, which I don't have ... — James Stone, Feb 15 '13 at 17:58
It looks like there's a newline in the code display in your post — Mark Baker, Feb 15 '13 at 18:03
Nah, it was fixed using single quotes, see below. It's strange ruby quirk it seems. — James Stone, Feb 15 '13 at 18:04

Colin M · Accepted Answer · 2013-02-15T18:00:53.503

7

Use single quotes instead of double quotes

Digest::MD5.hexdigest('9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@#@akskd9')

edited Feb 15 '13 at 18:00

answered Feb 15 '13 at 17:55

Colin M

13,010
3
38
58

1

@RomanMittermayr Then there must be a slight difference between the PHP and Ruby input in your code. I just ran this on my computer and got `bfa7df865d9f4aff62c4643d0e1cb33b` – Colin M Feb 15 '13 at 17:58
Yes, but I realized I was using single quotes and it makes a difference. Check my answer now. – Colin M Feb 15 '13 at 18:01
Yes single quotes it is!!! Why is that?? (I'll accept this in a minute or two when it let's me, but this fixes it). – James Stone Feb 15 '13 at 18:01
1

Because the string is evaluated differently inside of double quotes and the hash `#` character is throwing it off. To be honest, I'm not entirely sure why (since I believe ruby control sequence for including variables in strings is `#{...}` (notice the curly braces). – Colin M Feb 15 '13 at 18:02
6

`#@akskd9` will try and include the instance variable named `akskd9`. The critical part is the `#@` together, not just the `#`. – Tomdarkness Feb 15 '13 at 18:12
@Tomdarkness Gah! Forgot about the `@` sign. Thanks for commenting on this one - personally not a ruby guy. – Colin M Feb 15 '13 at 18:12
A bit more elaboration on the #@ and @## feature here http://stackoverflow.com/questions/10091156/why-does-this-string-interpolation-work-in-ruby – bradgonesurfing Feb 15 '13 at 19:18
1

Pro tip: don't use double quotes for strings unless you are interpolating or need the special escapes, default to single quotes so that double quotes will give you a heads up to check the string for interpolation. – mu is too short Feb 15 '13 at 19:47
@muistooshort Yeah, I use that philosophy in PHP as well. Actually, even when I could use double quotes, I use single and concat. Then it's VERY explicit about what I want. – Colin M Feb 15 '13 at 19:55

CCinkosky · Answer 2 · 2013-02-15T18:26:23.747

It is the combination of "#@" that makes it want to treat "@akskd9" at the end of the string as a variable.

For example:

@akskd9 = "foobar"
puts "9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@#@akskd9"

=> 9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@foobar

..without the # in there, then it ignores the @ symbol:

@akskd9 = "foobar"
puts "9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@@akskd9"

=> 9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@@akskd9

...interesting though, without the {...} after the #, it treats the rest of the string as a variable.

@ak = "foobar"
puts "9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@#@akskd9"

=> 9jdaksjdfosdjsljz91m1wms0zkzd0k0askd1m2l3!@3@

Ruby PHP MD5 Incompatible - How is this possible?

2 Answers2