Secure Database in cloud

Mohammad Ahmadian ahmadian@knights.ucf.edu

COP-6087University of Central Florida

PART 2

DbCrypt Goal: protect confidentiality and Integrity of data

ApplicationDB ServerSQL

Threat 1: passive attacks on DB

server

Threat 2: active/passive attacks on all servers

User 1

User 2

User 3

Proxy

1. Process SQL queries on encrypted data

2. Capture and enforce cryptographically access control in SQL: chain keys from user passwords to data item (Keygen)

user password

ApplicationDB Server

curious DB administrators

hackers curious cloud/employees physical attacks

SQL

User 1

User 2

User 3

Threat Model

Consider attacks on any part of the servers, Consider passive attack like modification of information in database by

malicious cloud insider

Threat 1: Active attack to connection the cloud

DB ServerSQL

Trusted

All queries are encrypted

Proxy

application queries unencrypted

Client & server side both are trustedThe session between client and db server is compromised

Under attack

The benefit of attackers are very low

Trusted

Threat 2: Passive attacks to DB Server

DB ServerSQL

Trusted

Perform SQL query processing on encrypted data

Proxy

application queries unencrypted

Client side enjoys issuing query without concerning about underlying security mechanisms in proxy DB server is unchanged It is impossible to attacker to change data without revealing to user

Under attack

1. Support standard SQL queries on encrypted data

2. Process queries completely at the DB server3. No change to existing DBMS

1. RND-Advanced Encryption Standard◦ Obs.: set of SQL operators is limited◦ Different encryption schemes provide different

functionality

2. OPE-Order Preserving Encryption◦ Enable to comparison, order by, join, sort, MAX,

MIN.

3. MAC –Message authentication code◦ Provides integrity for data element

Solution: Cryptographic techniques

?

Example

col1/rank col2/name

table1 (cinfo)

SELECT * FROM cinfo WHERE income= 100

x5a8c34

x934bc1x5a8c34

x5a8c34

x84a21c

x5a8c34

≥

x638e54

x638e54x922eb4

x1eab81

SELECT * FROM cinfo WHERE income= x5a8c34≥

Proxy

60100800100

?x5a8c34x5a8c34x5a8c34

x638e54x922eb4x638e54

X4be219x95c623

x2ea887

x17cea7

x638e54col3/salary

Application

Encryption Technics comparison

e.g., =, !=, GROUP BY, IN, COUNT, DISTINCT

Highest Scheme Operation Detail

RND None AES

HOM +, *

AES in CTR DET equality

e.g., Paillier

OPE orderBoldyreva et

al.’09

e.g., >, <, ORDER BY, SORT, MAX, MIN

first practical implementation

Security

AES

The Advanced Encryption Standard (AES) is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001. Rijndael is a family of ciphers with different key and block sizes. For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths: 128, 192 and 256 bits.

AES is one of secure block cipher for digital information. I adapt it with key size 128 bit for this project for encrypting text columns. One of negative point of AES is it’s speed, actually it’s key generation is not so fast.

AES

Order Preserving Encryption(OPE)Order Preserving encryption(OPE) is an encryption scheme whose deterministically preserves numerical order of plaintext in the ciphertext. For quick start, consider a random order-preserving function from M to N, so that |M|<|N|. Without loss of generality, we can consider M the set {1,2,...,M} and N likewise {1,2,...,N}. Now, pick M elements of N randomly and put them in order. Our function f:M → N is simply this ordered set. To encrypt i in M, just output the ith element of this list. Consider f is an order-preserving function which maps elements in domain to ordered list of elements of the range. Obviously, the elements of range can be divided in two categories of marked and unmarked. If an element is selected by f then it is member of marked otherwise it is member of unmarked category. Thus elements of the range are partitioned into the marked and unmarked subsets, as being balls in a bin. If we draw balls without replacement, the number x of marked balls we've drawn after y samples can be described by the Hyper Geometric Distribution(HGD)

OPE-Encryption

OPE-Decryption

Multi-user

What I did in this project I spend 3 weeks to install open source cryptdb

It failed because it is depended to lots of packages and libraries and there isn’t any documentation.

I spend 3 weeks to writing my own mysql-proxy It is almost 1200 lines of code in c++ and easy to

install. It needs to add some features to handle all type of datbases

Acknowledgment & Reference

John Singleton Salih Safa

Reference:1- CryptDB: Confidentiality for Database Applications with Encrypted Query ProcessingRaluca Ada Popa, Catherine Redfield, Nickolai Zeldovich, and Hari Balakrishnan MIT CSAIL

2-Order-Preserving Symmetric EncryptionAlexandra Boldyreva, Nathan Chenette, Younho Lee and Adam O'NeillGeorgia Institute of Technology, Atlanta, GA, USA

Questions & Demo