Review for CryptDB

The theft of sensitive data from users is always a big problem. The CryptDB wants to protect user's data without trusting DBMS or DBA (Database Administrator)s. To achieve that, CryptDB let DBMS to store all the encrypted data and process the SQL queries directly without having the decryption keys.

The main idea of CryptDB consists of three parts.
1.SQL-aware encryption strategy: We can directly perform SQL-query on data encrypted with current encryption schemes without knowing the decryption key. And CryptDB only a novel cryptographic construction for privacy-preserving joins. Then CryptDB uses these encryption techniques for data encryption.

2. adjustable query-based encryption: CryptDB can dynamically adjust the data encryption level on each data item in runtime. Basically, CryptDB initially use the strongest level encryption on each piece of data and then dynamically adjust the encryption level on the server.

3.onion of encryptions: CryptDB uses this techniques to only reveal the relation between the data items but no reveal of other data information or data relation not used in this query.

The difference of CryptDB from other previous works is that CryptDB is the first private system that supports all the operators on SQL query without modifying DBMS or clients applications.

For the trade-off, based on the evaluation side, I think the overhead of encryption / decryption is very high, especially in Sum operation.

I think CryptDB will still be influential since it proposes a system to achieve data encryption without modifying the DBMS or client app.