ABSTRACT
The paper presents the basics of cryptography. Furthermore, it shows the difference between the symmetric cryptosystem (which uses the same key in the encryption and decryption process) and asymmetric cryptosystem (cryptosystem with public key). The asymmetric cryptosystem RSA is explained in detail, as it is the use of cryptography in the Oracle database. The appendix shows the mathematical basis of the RSA cryptosystem and the implementation of its software (for presentation purposes).