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Hi all,
I want to create a string of alphanumeric values. Actually it is for security purpose. I am using C++ and I want the fuction for that...string must be like this:4gh5js83gk6l0s
what is the exact code to do this??
Can anybody help regarding this?? Plzzzzzzzzzzz
Best Regards,
Symbee
Do you mean you want to generate a random string?
Yes..!!
I want this for the security purpose..like..when I open application ,some random values must be sent to the system for the validation...
Can u help me to get this..
Thanx n regards
Symbee
I'm not at home right now. When I get there, I will send you an example of a program I made which generated a random word. That program generated a random word and used some letters more than the others. Thats why I used a char string, where it chooses a letter from:
And so on. If there's more of one letter, it appears more often.Code:char letters[]={"aaabccdeefghhiiijkkkll"};
I think your program can be made quite easily, because you can just use ASCII character values.
Once I get home I will post some examples.
ok maxorator ..thanx for yr kindness..
Send me those examples n also try to send me the code which also includes numbers with char like aa5bc72h1kc9
Thanx again..waiting for ur reply
regards
symbee
EDIT - you could do it with ASCII values, but it's simpler this way, IMOCode:srand( time(0) );
// letters_numbers is a string type which has all the small and capital letters, with numbers too
string letters_numbers = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
// This is where the 'random' string is stored
string RandomString = "";
for ( loop for whatever amount of times you want )
{
RandomString += letters_numbers[rand() % letters_numbers.size()];
// Possibly add 1 to the % letters_numbers.size()
}
cout<< "Random string: " << RandomString;
Thnx twomers:))
I will try this n will come back to u if would find ny trouble
regards
Symbee
Using rand() to generate your random string isn't very secure (at all).
I got the output....
:)thanx all
Symbee
Why do you need security when generating random things?Quote:
Originally Posted by Salem
Let's say you get e8rt1aadhse4y88t. Even if it sometimes repeats the last letter, it is not guessable.
I am still not home... long day... :(
Ya ..u r right max,
Actually I am working on symbian which is a mobile technology(u might be knowing) and the platform is c++. I want to send a random string of such values through SMS to the main server.
That seraver will create another string through some algorithm which uses our previously sent string.and will return it to the mobile. both would be validated on mobile also..n the purpose would be achieved!!(hope this explanation may not confuse u!!:))
So now I want to use some algorithm..So that the random string will be converted into some another string. which one would be best for this??
Regards,
Symbee
Lemme guess, you're trying to do this
http://en.wikipedia.org/wiki/Challen...authentication
Hi Salem,
Yes, you can say...!!The idea is same but they havn't give anything in C++ prospect:(
So anybody can help me to do the same???
Regards,
Symbee
rand() is deterministic; each value it returns is mathematically based on the previous value. It is not really random at all. If you srand() with the time, as many do, then simply knowing the approximate time the string was created could narrow the search to only a few thousand possibilities.Quote:
Originally Posted by maxorator
Even worse, if you had an app that seeded once and then generated many passwords, if you determined the seed value, you'd know every single password that it would generate until the generator was re-seeded.
This is true, but a cryptographic PRNG used correctly would suffice for security, even though it too would be deterministic.Quote:
rand() is deterministic; each value it returns is mathematically based on the previous value. It is not really random at all.
That is not the fault of rand(), but of the way the seeding was done.Quote:
If you srand() with the time, as many do, then simply knowing the approximate time the string was created could narrow the search to only a few thousand possibilities.
The point is that with the typical implementations of rand(), an attacker may be able to determine the seed value. With a cryptographic PRNG, an attacker's job would be considerably more difficult.Quote:
Even worse, if you had an app that seeded once and then generated many passwords, if you determined the seed value, you'd know every single password that it would generate until the generator was re-seeded.