LockNKey: Improvised Cloud Storage System using Threshold Cryptography Approach

In light of the current cloud security issues, this research focuses on developing a secure mechanism to improve the security of data stored in the cloud for computing service providers using threshold cryptography and encryption. While the data is being uploaded to cloud storage, it is vulnerable to attacks. Recent studies include distribution of keys for encrypted files to enhance the security. This research proposes a system which secures the data with the concept of threshold cryptography on a modified version of the RSA algorithm before uploading it to the cloud storage. The private key generated by the RSA algorithm is split up into N smaller parts or shares which can be stored at different places. The user would require a minimum k number of shares (where k is less than N) to recreate the private key and decrypt the data. The key is regenerated using the Lagrange interpolation algorithm which allows to reconstruct any polynomial of degree K minus 1 from K points on its curve. Thus, the system is even more protected since an attacker will not be able to decode the data even if he has as many as k minus 1 shares. Also, it is more secure in the manner that even if the legitimate user loses N minus k shares, they would still be able to decrypt the data by recreating the private key using the remaining k keys. Thus, in this manner by splitting the private key into a larger number of smaller shares, there is an increase in the security of the data being stored, added to this based on different input sizes there has been a decrease in the encryption time by 1.42 percent on the original RSA algorithm. A Graphical User Interface application is also built to make it easier for the user to secure their documents they want to store on cloud.