[siriusmd99]

Why would md5 hash string encryption be better and safer than my method?

Uniqueid = ( str[0] + str[1] + ... str[last char] ) * sqr(strlen(str))

Example :

str[ ] = "hello"

Uniqueid = (104 + 101 + 108 +108 + 111) * sqr(5) = 532 * 25 = 13300

Its simple and the strings are encrypted well. There cannot be when two strings have the same ID, because I do square operation to string length and the ID value grows geometrically.

So I wonder is there any leak in this method or something? I just made up this method and I don't want to complicate life with md5 or other stuff.

And also, I want to say that I don't want to make unique id for two equal strings but different timestamp. If I wanted that I could add get_systime() above the ID.

[klippy]

That's not encrypting, that's hashing (as is MD5).

There cannot be when two strings have the same ID, because I do square operation to string length and the ID value grows geometrically.

Subtract 1 from a character in the string, add 1 to another one (instead of 108 + 108 like in your example, have 107 + 109) and there - different strings, same ID.

I don't want to complicate life with md5 or other stuff.

How is that complicating anything? Just call one function and get the hash of a given string. Wouldn't be much different than your method.

We wouldn't have a need for MD5 (and other much more advanced and better algorithms) if logic behind hashing was that basic.


Anyway, what are you actually trying to do? Why do you need this?

[siriusmd99]

Yes, I forgot about different characters and the same length. But I can sum squares of each character's code.
Anyway...
So I can use md5 hashing but I it stores has as string. What's the point then? I want to reduce memory use and store just an ID to SQL not a whole string. Md5 function in Amxx is copying hash result as string. I want integer instead.

[HamletEagle]

Originally Posted by siriusmd99 Yes, I forgot about different characters and the same length. But I can sum squares of each character's code. Anyway... So I can use md5 hashing but I it stores has as string. What's the point then? I want to reduce memory use and store just an ID to SQL not a whole string. Md5 function in Amxx is copying hash result as string. I want integer instead.

str_to_num huh

[siriusmd99]

Originally Posted by HamletEagle str_to_num huh

Nope. It has letters.

Something like a5485d82ae55dac
I can't use str to num here. Not all symbols are digits.

[fysiks]

What are you actually trying to do with your string? As previously mentioned, a hash is not a method of encryption. You will never be able to get your original string from the hash.

Note that the string is actually a number represented as hexadecimal. So, it can be converted to a number. I don't think str_to_num() handles hex values.

[HamletEagle]

Originally Posted by siriusmd99 Nope. It has letters. Something like a5485d82ae55dac I can't use str to num here. Not all symbols are digits.

You still can use str_to_num, but you won't be able to convert back from the number to the hash. If you want to get a number from the hash and then convert it back you could to a stupid trick like that:

PHP Code:

#include <amxmodx>
#include <fakemeta>

public plugin_init()
{
    new const String[] = "test"
    new HashedString[34], OtherString[34]
    md5(String, HashedString)
    
    new Offset = engfunc(EngFunc_AllocString, HashedString) //get the offset
    
    global_get(glb_pStringBase, Offset, OtherString, charsmax(OtherString))//convert back to a string
    server_print("[%s] [%s] [%i] [%s]", String, HashedString, Offset, OtherString)
    
} 


Output:

[test] [098f6bcd4621d373cade4e832627b4f6] [41524840] [098f6bcd4621d373cade4e832627b4f6]

Note that allocating a string is an expensive operation so depending on what you want to do it may not be a good idea. As fysiks said, you should explain what you are trying to do.

[klippy]

MD5 outputs a 128-bit string, you can use a 4 element long array to represent it too.

[siriusmd99]

I don't need to convert it back. Just to get unique ID to save SQL.
Hash_column[0] = some hash
Hash_column[1] = some hash
And so on..
Then I read a text file and create an array to save hashes after I read string.
Like
fget string
Md5 hash
Str to num
And then save num to a global array
Hashes[i] = num

When player connects I get Hash_column from SQL and loop every ID to check if it's contained in Hashes[] global array.

So I just want str to num work without any engfunc and the generated integer id be unique so that there won't be different strings with same ID after using str to num. That's all.

[klippy]

When player connects I get Hash_column from SQL and loop every ID to check if it's contained in Hashes[] global array.

It seems that you are looking for hash maps (Tries). Given that you are using SQL, something can probably done with SQL queries too.

This looks like an XY problem; better describe the problem itself, not what you think the solution to the problem is.