This presentation introduces a new symmetric cryptosystem called "Rotating Disk." The security of this system is based on the difficulty of breaking a large number into its prime factors, a problem that is very hard to solve. 

In our method, a virtual disk is divided into p tracks and q sectors, where both p and q are large prime numbers. A special mask, generated using a simple random number method, is used to decide where to place the bits of the message during encryption. The plaintext is first turned into binary code, then written onto the disk following the pattern set by the mask, and finally, the encrypted message is read from the disk in a specific order. This approach combines basic ideas from number theory with the unpredictable nature of random systems to create a strong encryption method.