OJO. CUIDADO CON ESTO!
create or replace package data_cryption as
function BinaryConvert(mask char) return char;
function cryption(mask char,data char) return char;
end data_cryption;
/
create or replace package body data_cryption AS
function BinaryConvert(mask char) return char is
outer_loop number;
value number;
divisor number;
r1 varchar2(30);
begin
r1 := \'\';
value := ascii(mask);
divisor := 128;
for outer_loop in 0..7 loop
if trunc(value/divisor) = 1 then
r1 := r1 || \'1\';
else
r1 := r1 || \'0\';
end if;
value := value mod divisor;
divisor := divisor / 2;
end loop;
return r1;
end;
function cryption(mask char,data char) return char is
outer_loop number;
inner_loop number;
r1 varchar2(8);
r2 varchar2(8);
r3 number;
result varchar2(40);
divisor number;
begin
result := \'\';
for outer_loop in 1..length(mask) loop
r1 := BinaryConvert(substr(mask,outer_loop,1));
r2 := BinaryConvert(substr(data,outer_loop,1));
divisor := 128;
r3 := 0;
for inner_loop in 1..8 loop
if to_number(substr(r1,inner_loop,1))+to_number(substr(r2,inner_loop,1))=1 then
r3 := r3 + divisor;
end if;
divisor := divisor / 2;
end loop;
result := result || chr(r3);
end loop;
return(result);
end;
End data_cryption;
/
/* ____________ Prueba ________________ */
set serveroutput on
declare
result varchar2(30);
mask varchar2(30);
begin
mask := \'abc\'; /* Must be greater or equal to the value that
will be \"Encrypted\" */
result := data_cryption.cryption(\'ABD\',mask); /* \"Encrypt\" */
dbms_output.put_line(result);
result := data_cryption.cryption(result,mask); /* \"Decrypt\" */
dbms_output.put_line(result);
end;
/
