Communication of Confidential Documents Through Email using Hybrid and Key-Exchange Algorithm

One of the fastest and most low-cost means of communication is Email. Most of the people made Email as part of their lifestyle, it changes the way of working. Email can be sent to an individual or group. It is more and more important to protect the transmission of data in the communication network. The existing PGP protocol uses RSA algorithm, it is not user-friendly, more complex in nature, slow encryption and both users need to use the same version of software. The aim of this project is to develop a new hybrid algorithm combining the benefits of AES, RSA and Polybius square cipher algorithms to improve the execution speed, improve security and transfer the secret key in a secured manner. This algorithm uses CFB mode instead of CBC mode for encryption to produce a unique output. The key of AES algorithm is now encrypted using RSA algorithm, but RSA only accepts numeric values. Using Polybius square cipher algorithm, the key value gets converted into numeric value. The key exchange algorithm will help us to prevent the attacks made to disclose the key which is transferred between client and receiver. The combination of hybrid and key exchange algorithm is to ensure the confidential documents are securely transferred.