Poral Nagaraja, Ashwini Hongal
Cloud computing is a recently developing technology which can be used to access and store data easily. Cloud storage will provide good reliability and lowest cost. Its functionality is sharing data with other users securely, efficiently and flexibly in cloud environment. We introduce a special type of public key encryption called as Key- Aggregate cryptosystem (KAC). In KAC user encrypts message with public key and also with an identifier of cipher text. In KAC any set of secret keys can be aggregated and made them as single key.