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Algorithms

 
AnswerRe: I need help decrypting an encrypted text (I also got cleartext examples) Pin
mbyamukama1-Sep-09 21:09
mbyamukama1-Sep-09 21:09 
GeneralRe: I need help decrypting an encrypted text (I also got cleartext examples) Pin
SimpleData2-Sep-09 0:03
SimpleData2-Sep-09 0:03 
QuestionHelp needed. Do you know whether I can use mean-shift to solve this problem? [modified] Pin
superwave30-Aug-09 1:39
superwave30-Aug-09 1:39 
QuestionFinding a polygon that encloses a set of points Pin
gantww28-Aug-09 7:49
gantww28-Aug-09 7:49 
AnswerRe: Finding a polygon that encloses a set of points Pin
Randor 28-Aug-09 8:15
professional Randor 28-Aug-09 8:15 
AnswerRe: Finding a polygon that encloses a set of points Pin
ely_bob18-Nov-09 15:12
professionalely_bob18-Nov-09 15:12 
QuestionEncrypt/Decrypt .EXE Pin
gencast27-Aug-09 20:48
gencast27-Aug-09 20:48 
AnswerRe: Encrypt/Decrypt .EXE Pin
Moreno Airoldi28-Aug-09 1:33
Moreno Airoldi28-Aug-09 1:33 
By what you describe it seems your problem is having strings in your exe that can be read by opening it with an hex editor.

If that's the case, then you can encrypt your strings using any encryption algorithm you like, and implement a decoding routine in your software. Each time you use an encrypted string, you must decode it. For example (C#):

C#
string MyEncodedString = "#@SIRJI3893N";

MyTextBox.Text = DecodeString(MyEncodedString);


There are many encryption algorithms you can use. The simplest are based on XORing and byte swapping. They are very fast and easy to implement but must contain a fair number of operations to make it less easy to understand the encryption method.

If you use .NET, you can also have a look at the System.Security.Cryptographic namespace, which provides standard encryption algorithms. These are stronger but depend on an encryption/decryption key, which must be embedded in the exe and must be obfuscated in some way (XORing and swapping again or similar).

About .NET, you can also make your life easier by simply using an obfuscator which provides string encryption, like eazfuscator[^]. It will do all the work for you.

You should also be aware that there is no way to stop a determined attacker with enough patience and time: he will reverse engineer your decoding routine and apply it to your strings. That said, if you implement it properly, it will take time and sweat to do that. Smile | :)

2+2=5 for very large amounts of 2
(always loved that one hehe!)

QuestionAlgorithm for a de-captcha project Pin
Sepirothftw27-Aug-09 10:33
Sepirothftw27-Aug-09 10:33 
GeneralRe: Algorithm for a de-captcha project Pin
harold aptroot27-Aug-09 11:02
harold aptroot27-Aug-09 11:02 
AnswerRe: Algorithm for a de-captcha project Pin
Eddy Vluggen1-Sep-09 2:34
professionalEddy Vluggen1-Sep-09 2:34 
Answeroff topic Pin
Sauce!8-Sep-09 6:54
Sauce!8-Sep-09 6:54 
GeneralRe: off topic Pin
ely_bob18-Nov-09 15:18
professionalely_bob18-Nov-09 15:18 
AnswerRe: Algorithm for a de-captcha project Pin
TAREQ F ABUZUHRI14-Nov-10 23:01
TAREQ F ABUZUHRI14-Nov-10 23:01 
QuestionImage segmentation help Pin
kabirbdboy26-Aug-09 3:29
kabirbdboy26-Aug-09 3:29 
AnswerRe: Image segmentation help Pin
Alan Balkany26-Aug-09 8:13
Alan Balkany26-Aug-09 8:13 
GeneralRe: Image segmentation help Pin
kabirbdboy27-Aug-09 2:32
kabirbdboy27-Aug-09 2:32 
GeneralRe: Image segmentation help Pin
Alan Balkany27-Aug-09 3:16
Alan Balkany27-Aug-09 3:16 
GeneralRe: Image segmentation help Pin
Tim Craig27-Aug-09 8:27
Tim Craig27-Aug-09 8:27 
QuestionHelp decoding a friendly message Pin
BillyTed24-Aug-09 13:33
BillyTed24-Aug-09 13:33 
AnswerRe: Help decoding a friendly message Pin
Tim Craig24-Aug-09 15:09
Tim Craig24-Aug-09 15:09 
AnswerRe: Help decoding a friendly message Pin
Ian Shlasko25-Aug-09 7:41
Ian Shlasko25-Aug-09 7:41 
AnswerRe: Help decoding a friendly message Pin
supercat926-Aug-09 12:26
supercat926-Aug-09 12:26 
GeneralRe: Help decoding a friendly message Pin
Ian Shlasko27-Aug-09 8:38
Ian Shlasko27-Aug-09 8:38 
GeneralRe: Help decoding a friendly message Pin
BillyTed27-Aug-09 12:23
BillyTed27-Aug-09 12:23 

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