A cryptographic system (CS) is provided. The CS (500) is comprised of a data stream receiving means (DSRM), a ring generator (RG) and an encryptor. The DSRM (602) provides a data stream (DS). The RG (400) includes a computing (404-408), converting (404-408) and permutation (410) means. The computing means is configured to perform RNS arithmetic operations to express a random number in a random number sequence as RNS residue values (RNSRV). The converting means is configured to convert each RNSRV to a relatively prime number system so that each RNSRV includes at least one digit. The permutation means is configured to generate an arbitrary permutation ordering of output sequence numbers (OSNs) using a select combination of digits associated with each RNSRV. The arbitrary permutation ordering is determined using a cyclic structure. The encryptor is configured to generate a modified data stream by combining the OSNs and DS.