Efficient and fine-grained sharing of encrypted files

In this work, we present an efficient fine-grained sharing approach of encrypted files. A concept named safe capsule (SC) is proposed as the organization unit for files. By using safe capsule, user can provide one of the fine-grained access permissions of their own data to others, such as read-only. Data are encrypted(decrypted) transparently when writing(reading) to keep its privacy.