encryption and decryption of spl chars

[bang_dba]

hi,

I have a string of Special characters.
I need to encrypt each of the special character to another value in the string, without repeatation, so that i can decrypt it back, for a particular seed value.


string_val=$%&()~'*,-/:;=?_

substr(string_val, mod (instr(string_val,curr_char) + 545,length(string_val)),1)

Curr_char is the value passed to get the encrypted one.

I am getting repeations (for eg., * and , are getting encrypted to $) due to which i am not able to decrypt.

can somebody suggest changes to the above query, so that there wont be any repeatations.

[gandolf989]

Why don't you just use the Obfuscation Toolkit?

[bang_dba]

Due to some bottlenecks in the application, i cannot use it.
I want a common algorith, which works same in front end and back end.

[DaPi]

Your problem is that MOD( , n) gives values from 0 to n-1 and SUBSTR(x, 0, 1) is interpreted as SUSBTR(x, 1, 1). Check with this

declare
	string_val varchar(30) := '$%&()~''*,-/:;=?_';
	curr_char  varchar(1);
	out_line   varchar(100);
begin
	for i in 1..length(string_val) loop
		curr_char := substr(string_val, i, 1);
		out_line  := curr_char||' gives '||
			substr(string_val, mod (instr(string_val,curr_char) + 545,length(string_val))+1,1);
		dbms_output.put_line(out_line);
	end loop;
end;
/

P.S. mod(545,16)=1 why be so complicated?

[bang_dba]

Thx Dapi