[PHP] str_replace - is this even possible?

[RedPillow]

Hi again.
I'd like to make simple crypter by myself, this is what I've done so far:

Code: PHP [Select]

1. //This is the key-table for crypter.
2. $cryptkey = array('0' => 286, '1' => 949, '2' => 695, '3' => 348, '4' => 438, '5' => 977,
3.         '6' => 320, '7' => 418, '8' => 970, '9' => 482, '[' => 466, ']' => 770, '.' => 569,
4.         ' ' => 242, '-' => 166, 'A' => 583, 'B' => 575,  'C' => 247,  'D' => 564, 'E' => 192,
5.          'F' => 513,  'G' => 653,  'H' => 605,  'I' => 450,  'J' => 404,  'K' => 831,  'L' => 315,  'M' => 953,
6.           'N' => 439,  'O' => 266,  'P' => 231,  'Q' => 633,  'R' => 881,  'S' => 113,  'T' => 935,  'U' => 559,
7.            'V' => 318,  'W' => 927,  'X' => 906,  'Y' => 463,  'Z' => 184, 'a' => 263,  'b' => 453,  'c' => 208,
8.            'd' => 591,  'e' => 511, 'f' => 343,  'g' => 969,  'h' => 415,  'i' => 420,  'j' => 175,  'k' => 410,
9.            'l' => 295,  'm' => 265, 'n' => 877,  'o' => 200,  'p' => 837,  'q' => 913,  'r' => 515,  's' => 262,
10.            't' => 524,  'u' => 874, 'v' => 525,  'w' => 700,  'x' => 670,  'y' => 918,  'z' => 290, '<' => 331,
11.            '>' => 533, "'" => 425, ',' => 101, ':' => 495, '$' => 114, '\\' => 268, '/' => 721, '=' => 454);
12. //Don't mind about some fails in the table ... solving them later.
13.  
14. //This is the string we're going to crypt.
15. $notcrypted1 = "[$curdate] - Rotation was <font color = '$color'><b>$rotation</b></font> degrees, done by <b>$ip</b>, who says: ''<b>$msg</b>''\r\n";
16.  
17. //Splitting the string here. (is this even needed?)
18. $split1 = str_split($notcrypted1);
19.  
20. //And this is the problem area
21. foreach ($split1 as $char) {
22.         foreach ($cryptkey as $char2 => $key2) {
23.                 $crypted1 = str_replace($char, $key2, $notcrypted1);
24.                 }
25.         }
26.  
27. //Im using this PHP.net's example
28.  
29. // Provides: Hll Wrld f PHP
30. $vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");
31. $onlyconsonants = str_replace($vowels, "", "Hello World of PHP");

So basically, it is supposed to replace the characters in the $notcrypted1 with the key-table's corresponding int value.
But the problem is, that I'd like to know if there's any way to tell the program to switch the character it is going trought with the key-table's corresponding int value ... And like without doing 3000 if's.

Since it can replace the vowels with blank in the example - is it possible to switch the characters with the ints in my code?
My brains are jamming with this one ... I know it will not work like this and I even know why it isn't working - I just can't find a way to solve it ...


I wouldn't want to do it like so:

Code: PHP [Select]

1. foreach ($split1 as $char) {
2.         foreach ($cryptkey as $char2 => $key2) {
3.                 if ($char == "A") {
4.                         $crypted1 = str_replace($char, "A", $notcrypted1);
5.                 }
6.         }

[JoTo]

Hi RedPillow,

i think your problem is, that str_replace finds already replaced characters in your string and replace it again and again and again.

This version of your slightly adapted script works for me. Maybe give it a try.

Code: PHP [Select]

1. <?php
2. //This is the key-table for crypter.
3. $cryptkey = array('0' => 286, '1' => 949, '2' => 695, '3' => 348, '4' => 438, '5' => 977,
4.                   '6' => 320, '7' => 418, '8' => 970, '9' => 482, '[' => 466, ']' => 770,
5.                   '.' => 569, ' ' => 242, '-' => 166, 'A' => 583, 'B' => 575, 'C' => 247,
6.                   'D' => 564, 'E' => 192, 'F' => 513, 'G' => 653, 'H' => 605, 'I' => 450,
7.                   'J' => 404, 'K' => 831, 'L' => 315, 'M' => 953, 'N' => 439, 'O' => 266,
8.                   'P' => 231, 'Q' => 633, 'R' => 881, 'S' => 113, 'T' => 935, 'U' => 559,
9.                   'V' => 318, 'W' => 927, 'X' => 906, 'Y' => 463, 'Z' => 184, 'a' => 263,
10.                   'b' => 453, 'c' => 208, 'd' => 591, 'e' => 511, 'f' => 343, 'g' => 969,
11.                   'h' => 415, 'i' => 420, 'j' => 175, 'k' => 410, 'l' => 295, 'm' => 265,
12.                   'n' => 877, 'o' => 200, 'p' => 837, 'q' => 913, 'r' => 515, 's' => 262,
13.                   't' => 524, 'u' => 874, 'v' => 525, 'w' => 700, 'x' => 670, 'y' => 918,
14.                   'z' => 290, '<' => 331, '>' => 533, "'" => 425, ',' => 101, ':' => 495,
15.                   '$' => 114, '\\' => 268, '/' => 721, '=' => 454);
16. //Don't mind about some flaws in table ... solving them later.
17.  
18. // Just some dummy values to keep PHP happy :)
19. $curdate = "03/28/2011";
20. $color = "#ffffff";
21. $rotation = "RoundItGoes";
22. $ip = "192.168.0.1";
23. $msg = "Hello world!";
24.  
25. //This is the string we're going to crypt.
26. $notcrypted1 = "[$curdate] - Rotation was <font color = '$color'><b>$rotation</b></font> degrees, done by <b>$ip</b>, who says: ''<b>$msg</b>''\r\n";
27.  
28. //Splitting the string here.
29. $split1 = str_split($notcrypted1);
30.  
31. // Replace the characters in the string with their crypted equivalents
32. foreach($split1 as $key => $value)
33. {
34.     if(array_key_exists($value, $cryptkey))
35.         $split1[$key] = $cryptkey[$value];
36.     else
37.     {
38.         // An error occurred, the character is not present in the cryptkey table
39.         // do sth. like outputting an error or inserting a special number or the original
40.         // character or whatever
41.         print "OOPS! An error occurred. Do something, QUICK! :)";
42.     }
43. }
44.  
45. // Joining again to get back a single string
46. $crypted1 = implode("", $split1);
47.  
48. // Output the crypted result
49. print "\nCrypted result is: <".$crypted1.">\n";
50. ?>

I get this result string from it:
Crypted result is: <466286348721695970721695286949949770242166242881200524263524420200877242700263262242331343200877524242208200295200515242454242425#343343343343343343425533331453533881200874877591450524653200511262331721453533331721343200877524533242591511969515511511262101242591200877511242453918242331453533949482695569949320970569286569949331721453533101242700415200242262263918262495242425425331453533605511295295200242700200515295591!331721453533425425
>

What looks correct for me, in the way you described your goal, when i check some samples manually.

Hope this helps!

Greetings
JoTo

[RedPillow]

Oh my god, it works perfectly! THAAAANKS!
I was worried that nobody wouldn't make any sense of what I want to achieve  

Now, to reverse that back ... Im going to seek for function which switches the key-table's keys with values like so:

OLD:

Code: PHP [Select]

1. $cryptkey = array('0' => 286, '1' => 949, '2' => 695);

NEW:

Code: PHP [Select]

1. $cryptkey = array('286' => 0, '949' => 1, '695' => 2);

Edit: array_flip seems to do the work.

[JoTo]

Hi RedPillow again,

YW!

Yes, array_flip exchanges keys with values and vice versa in an array.

You can use the same slightly changed lines to reverse the cryption.

Just split the crypted string with str_split again and use the length parameter with value 3 to get chunks of 3 chars in each array element.
Then use the same foreach construct to search for keys (formerly the values) in cryptkey and replace it by the values (formerly the keys) and you should be there.

Good luck
JoTo

[Veign]

Might be easier, and faster to create two arrays: Keys, Values and then use the 'array' find/replace aspect of the str_replace function.

Sample (air-code):
// The setup
$keys = array('a', 'b', 'c');
$values = array('263', '453', '208');

$to_encrypt = 'a b c - abc';
$my_encrypted = str_replace($keys, $values, $to_encrypt);

No loop required.  Much more efficient.

[RedPillow]

Since I got your attention already, I'll ask if anyone knows, if it is possible in anyway for random <|p> and <|/p> -tags to get insterted into my code.
ALSO, str_replace wont find em either.

This is the output, don't mind about the contents  

Code: Text [Select]

1. <p>[18.26.23] - Rotation was <font color = 'orange'><b>225</b></font> degrees, done by <b>127.0.0.1</b>, who says: '<b>HIGHWAY|||</p><p>|||-CHESS BOARD|||</p><p>|||</b>'

I've highlighted the tags with '|||'s, which cause problem and I assure you, that I've gone trought EVERY FILE RELATED trying to find where those tags pop-up.
I've tried using find in text-editor, I've tried to strip and trim them and no I don't know what to do anymore...

This is just my foolish theory but ... might it be possible, since 'HIGHWAY' and 'CHESSBOARD' are obtained from text-file,
that they somehow contain invisible tags or something after them? Like HIGHWAY<|/p><|p> ?

[Veign]

No such thing as invisible tags in a text file.  Your code has to be adding them or the text files have to already contain them.  Text files have 0 knowledge of HTML.

[RedPillow]

Still weird tho ... I can print ie. CHESSBOARD as much as I want and it always puts <|/p><|p> after the word.  

[Veign]

If you're taking raw text from a text file, processing it and spitting out some cleaned/washed version then your code is adding it or it exists in plain site.  No other options.

[JoTo]

Hi Veign,

i was thinking about the array functionality of str_replace as well before i posted my solution of course. Problem is, that the replacements contain characters that will be replaced again (are in the search array).

E.g. if an "E" gets replaced with "012" and a "1" with "345" you end up with "03452" when using this approach. I've tested it first before i came back to my posted solution. As the characters in his string are random, you cant find an order of the search array that prevents this "reentrance".

Seems str_replace is not made for that you replace sth. with sth. that is in the search array. So this approach is not more effective but just won't work at all. Therefore this workaround.

For the other point i must agree with Veign. No black magic or voodoo here. Either the tags are in your source text already or your code adds them.

Greetings
JoTo

[Veign]

You are correct JoTo.  Not sure why I thought it would work.  Makes sense that it wouldn't.  Its loops through the already-replaced results looking to replace more items.  What they need is flag that would prevent an item from being replaced twice with the order of replace dictated by the order of the arrays passed into the function.

[JoTo]

Hi Veign,

glad that you proofed it. I just thought i am too dumb again to use the str_replace function correctly and gave out a bad advise.

Happy replacing all
JoTo

[RedPillow]

The <|/p> and <|p> tags somehow come from joining these two together:

$Firstpart[$rand] . $SecondPart[$rand];

[Veign]

Nope.  Didn't come from joining.  Code constructs have no clue what HTML is.  The variable had to have already contained the information.