Abstract—In this paper the development of a software to encrypt messages with asymmetric cryptography is presented. In particular, is used the RSA (Rivest, Shamir and Adleman) algorithm to encrypt alphanumeric information. The software allows to generate different public keys from two prime numbers provided by the user, the user must then select a public-key to generate the corresponding private-key. To encrypt the information, the user must provide the public-key of the recipient as well as the message to be encrypted. The generated ciphertext can be sent through an insecure channel, so that would be very difficult to be interpreted by an intruder or attacker. At the end of the communication, the recipient can decrypt the original message if provide his/her public-key and his/her corresponding private-key. or a courier. Figure 1 shows a block diagram of the symmetric key cryptography [3]. The key exchange problem becomes even more difficult if many people want to exchange encrypted messages, for example on the internet. If a network communication system has n users and any two of them exchange a key, then n(n-1)/2 secret key exchanges are necessary and all those keys have to be stored securely [4].

Abstract—In this paper the development of a software to encrypt messages with asymmetric cryptography is presented. In particular, is used the RSA (Rivest, Shamir and Adleman) algorithm to encrypt alphanumeric information. The software allows to generate different public keys from two prime numbers provided by the user, the user must then select a public-key to generate the corresponding private-key. To encrypt the information, the user must provide the public-key of the recipient as well as the message to be encrypted. The generated ciphertext can be sent through an insecure channel, so that would be very difficult to be interpreted by an intruder or attacker. At the end of the communication, the recipient can decrypt the original message if provide his/her public-key and his/her corresponding private-key. or a courier. Figure 1 shows a block diagram of the symmetric key cryptography [3]. The key exchange problem becomes even more difficult if many people want to exchange encrypted messages, for example on the internet. If a network communication system has n users and any two of them exchange a key, then n(n-1)/2 secret key exchanges are necessary and all those keys have to be stored securely [4].