Preserving Privacy of Data in Distributed Systems Using Homomorphic Encryption

Distributed systems like cloud platforms are being used widely in recent times. However, such platforms face a major issue of data storage on cloud in terms of security. If data on the cloud is not encrypted, it can be accessed by unauthorized members. This violates the confidentiality of the data. If data is stored in an encrypted format, every authorized party member will have to decrypt the data first in order to perform operations on it and then encrypt it back to upload it on the distributed platform. This has to be done every time, and every member performs operations on data. Needles to say, it complicates the entire procedure of sharing data and a lot of time is wasted in encrypting and decrypting data even for small operations like searching and sorting. To avoid these complications, this paper suggests a way to store data on cloud by homomorphically encrypting it. Homomorphic encryption allows user to compute on encrypted data without the need of decrypting it. In this paper, elliptic curve cryptography (ECC) is used for homomorphic encryption of data. The size of the ciphertext generated by ECC is smaller than the ciphertext generated by other encryption schemes. As cloud is mostly used for storing databases, this paper further employs searching and sorting techniques on the encrypted data.