Conceptual Framework for Lightweight Ciphertext Policy-attribute

based Encryption Scheme for Internet of Thing Devices

Jasni Mohamad Zain

, Norhidayah Muhammad

Faculty of Computer & Mathematical Sciences, Universiti Teknologi Mara, 40450, Shah Alam, Selangor, Malaysia

Keywords: Cryptography, ABE, CP-ABE, Lightweight Cryptography, Internet of Thing.

Abstract: The paper proposes a conceptual model for data security in the Internet of thing devices. Estimated by Jumoki

in early 2018 to 2022, there will be about 18 billion devices connected IoT. Therefore many issues concern

in IoT devices especially in data security. Cryptography with lightweight features is one of focus area by

researchers to develop a powerful cryptography scheme for IoT devices. Lightweight cryptography scheme

has been discussed and proposed widely recently. There are AES, PRESENT, Hash algorithm declared as a

lightweight algorithm under consideration in ISO/IEC 29192 “Lightweight Cryptography”. Unfortunately

these lightweight algorithm is one-to-one communication cryptography technique. This algorithm is suitable

to be implemented for individual or for small group communication. It is however not suitable to be

implemented in a big company as it involves many users and become a bottleneck. Therefore we propose a

lightweight Ciphertext Policy-Attribute Based Encryption (CP-ABE) algorithm to implement in IoT devices.

CP-ABE algorithm is one-to-many technique suitable for secure grouping communication, but this algorithm

is not a lightweight features. Therefore this paper proposes a lightweight CP-ABE algorithm for IoT devices.

1 INTRODUCTION

Cryptography was known as encryption become

an important thing in data security, especially

enabling safe internet communications in cloud

computing. In cryptography, lightweight issues have

long been identified and many studies have been

conducted in producing more lightweight

cryptography methods especially for constrain device

such as IoT device. Lightweight cryptography was

standardized with the properties of lightweight

cryptography discussed in ISO/IEC 29192 (Katagi &

Moriai, 2008). In ISO/IEC 29192, lightweight

properties are described based on target platforms.

Cryptographic algorithm tailored with

constrained resources including RFID tags, sensors,

contactless smart cards, health-care devices and so

on. Figure 1 show IoT devices role was connected

today. In hardware implementations, chip size and/or

energy consumption are the important measures to

evaluate the lightweight properties. In software

implementations, the smaller code and/or RAM size

are preferable for the lightweight applications.

Security solutions need to consider the efficiency and

lightweight requirements if they want to produce a

method that can be used on lightweight devices to

ensure that it does not increase the processing time

(Yang et al., 2016).

AES was known as lightweight cryptography if

compared to RSA because AES is a symmetric key

cryptography, it's using a small size of keys and only

has one key for both encrypting and decrypting

processes. Similarly with IBE, many researchers have

developed IBE which is more lightweight and

suitable for implementation in constraint devices. But

all of these algorithms are for one-to-one

communication, it is better suited for communication

between individuals and small groups that do not

involve many users. To meet the security

requirements in the cloud system, one-to-many

communication is required to facilitate data sharing

and to ensure data security.

Previously people familiar with some well-known

cryptography algorithms such as AES, RSAs are

commonly used to ensure data security, but it

provides problems for users to share data or

ciphertext and requires a lot of steps to share data with

many users because those algorithm is one-to-one

communication encryption technique (Yuan, 2016).

Zain, J. and Muhammad, N.

Conceptual Framework for Lightweight Ciphertext Policy-attribute based Encryption Scheme for Internet of Thing Devices.

DOI: 10.5220/0010043303790383

In Proceedings of the 3rd International Conference of Computer, Environment, Agriculture, Social Science, Health Science, Engineering and Technology (ICEST 2018), pages 379-383

ISBN: 978-989-758-496-1

379

Figure 1: Role of IoT devices (Agarwal, 2015)

In one-to-many technique, one ciphertext can be

accessed by many users as long as it meets the access

policy specified in the ciphertext. This makes it easy

for the data owner because it does not have to send

one by one the same ciphertext to different users. This

method is very efficient for a large company that has

many users (Vaanchig et al., 2016). Goyal first person

who introduced the concept of grouping by

developing an Attribute based encryption (ABE).

Then Sahai and Waters (2005) introduce (CP-ABE)

more efficient because users have the right to

determine who is eligible to access the ciphertext.

Many encryption algorithm can offer short

decryption keys. For example, identity-based

broadcast encryption (Delerablée, 2007), identity-

based encryption with traitor tracing (Guo et al.,

2012), multi-identity single-key decryption (Guo et

al., 2013). Unfortunately, a few researcher in

attribute-based encryption scheme offers short

decryption keys. CP-ABE Instead of decryption key,

ciphertext is also have problem with the size because

it’s depend on number of Boolean in access policy.

Therefore key design criteria in a CP-ABE scheme

should include constant size secret key and constant

size ciphertext, as well as a cost efﬁcient mechanism

for encryption and decryption.

2 RELATED WORK

Sahai and Waters (2005) made some initial steps to

improve the primitives existing encryption scheme

with one-to-one communication features by

introduced the concept of Attributed-Based

Encryption (ABE). The idea of ABE is grouping

technique, means that user or decryptor will be scale

in group. Therefore, one ciphertext can be decrypted

by one group of users with certain attribute, stated in

access policy by encryptor. ABE scheme has obvious

advantages in terms of eﬃciency and is ﬁt for large

scale network environment, such as cloud systems. In

an ABE system, a user’s keys and ciphertexts are

labeled with sets of descriptive attributes and a

particular key can decrypt a particular ciphertext only

if there is a match between the attributes of the

ciphertext and the user’s key.

The ABE scheme is allowed for decryption when

at least k attributes overlapped between a ciphertext

and a private key. While this primitive was shown to

be useful for error-tolerant encryption with

biometrics, the lack of impressibility seems to limit

its applicability to larger systems. Attribute-based

encryption (ABE) enforces encrypted data to be

decrypted with a secure access control mechanism

that the assigned attributes must satisfy the access

policies associated with ciphertext and private keys.

ABE has become a promising cryptographic

primitive providing one-to-many encryption.

2.1 Ciphertext Policy-attribute based

Encryption

After the notion of Attribute-based Encryption (ABE)

was introduced by Sahai and Waters (2005), After

that Goyal, Pandey et al. (2006) has proposed the ﬁrst

KP-ABE system, in which ciphertexts are associated

with attributes, and secret keys are associated with

access policies. Then BSW (Bethencourt, Sahai et al.

2007) has proposed CP-ABE scheme contrast with

KP-ABE where attribute is associated with private

key and access policy is associated with ciphertext

and become better than Key Policy-Attribute Based

Encryption (KP-ABE) based on specification of CP-

ABE provide fine-grained access control, CP-ABE

scheme in which the data owner hold direct control

on access policy and decide who should or should not

have access to the ciphertext. Then, Cheung and

Newport (Cheung & Newport, 2007) proposed

another CP-ABE in which the access structures are

AND gates

. Both scheme is based on bilinear map

and pairing based cryptography practically

implementing fine grained access control for data

owner to control deep security and very usable in

cloud system (Zain, 2010).

Table 1 show previous research focuses on

constant ciphertext and a constant private key. The

proposed algorithm is focused on one either private

key or ciphertext. Schemes with constant size

ciphertexts (Zhang et al., 2014), (Emura et al.,

ICEST 2018 - 3rd International Conference of Computer, Environment, Agriculture, Social Science, Health Science, Engineering and

Technology

380

2009),(Herranz et al., 2010) and constant size secret

keys (Emura et al., 2009),(Guo et al., 2014) with an

expressive access structure based on bilinear maps

have been proposed. According to (Zheng et al.,

2015) and (Li et al., 2014), the schemes based on

bilinear maps, which is signiﬁcantly more costly than

schemes based on conventional cryptosystems.

Besides that, even though Emura makes the size is

constant, but it uses the structure (n, n) threshold.

Where the threshold property is the number of

attributes in the access structure and the user attribute

in the private key must be the same. Thus, designing

a cost efﬁcient and expressive access structure CP-

ABE with the constant size secret keys and

ciphertexts using conventional public-key

cryptosystems remains a research challenge (Liew et

al., 2013).

Table 1: CP-ABE scheme with constant private key and

constant ciphertext

Author

Size

Private Key Ciphertext

BSW(Bethencourt

et al., 2007)

(2|A| + 1) G

(2|P| + 1) G +

(Herranz et al.,

2010)

(n + |A|) G 2G + G

(Emura et al., 2009) 2G 2G + G

(Zhang et al., 2014) (n +1) G 2G + G

(Guo et al., 2014) 2G

(n - |P| + 2 )

G + G

+ L

(Odelu et al., 2017) 2G 3G + L

2.2 Proposed Conceptual Model

The weakness of CP-ABE is in terms of size

decryption key and ciphertext, because it’s growing

linearly with the number of attributes, if the number

of attributes is more, then the size key will be bigger

because attribute combined with the key. And this

will be a barrier to constrain devices such as IoT.

Each device has a different number of attributes. The

challenge is to produce a constant size ciphertext, and

making the size ciphertext is not dependent on the

number of boolean in the access policy (Odelu et al.,

2017). As well as the challenge for generating a size

private key that is constant and independent of the

size attribute. This is because the attribute will be

combined with the user private key and it should

match the boolean in the access policy (Ambrosin et

al., 2016). Thereby enabling the process decryption to

succeed.

As shown in figure 2, this is theoretical

framework

proposed. Four important component involved in this

framework. The first is the key authority or key

center. The key center will generate a public key and

also a private key for the user. It also has the power

to verify the user's status by ensuring that the attribute

used by the user is correct. Therefore the key

authority plays a very important role in ensuring data

security. The second is data owner. The data owner is

the individual who will encrypt the data and he also

will determine who has the right to access the data.

The group of user that has access to the data will be

specified in the access policy, and the access policy

will be merged together with the ciphertext.

Third

component is cloud, after data owner

encrypts the data and put the ciphertext to cloud.

Cloud is a storage that gathers thousands of servers

and provides client service storage according to user

requirements. Data security needs to be emphasized

in cloud storage to ensure data security as data

intrusion can occur easily. The forth is IoT devices.

IoT devices become a new phenomenon today and

forward. IoT devices are used today such as sensors

for safety, medical, and so on systems. These devices

have a lack of resources such as a battery, memory

size, and processor. Therefore it requires a

lightweight algorithm and a small size of data.

Figure 2: Conceptual Framework for CP-ABE algorithm in

IoT devices

As shown in picture 3, there are four algorithms

in the CP-ABE scheme. The first is setup algorithm,

master public key and master secret key will be

generated. Master public key will be used in

encryption algorithm, keygen and also decryption

algorithm. While the master secret key will be used to

generate a private key in the algorithm keygen.

The second algorithm is encryption. After the

master public key is generated, the data owner can

apply from the key authority and can encrypt the data

Conceptual Framework for Lightweight Ciphertext Policy-attribute based Encryption Scheme for Internet of Thing Devices

381

using the master public key that is given and also

defines the access policy for the ciphertext. Only the

attributes mentioned in the access policy that will

successfully access the ciphertext.

The third algorithm is keygen. Keygen algorithm

operates to generate decryption key or private key for

the user to decrypt the ciphertext. The key authority

will validate user attribute and then use the master

secret key and combined with user attribute to create

user private key.

The fourth algorithm is decryption. In this

algorithm, the user or IoT device will use the private

key that has been generated in the keygen algorithm

to decrypt the ciphertext. If the attribute contained in

the private key match with the attribute in the access

policy then the process decrypt will succeed.

3 CONCLUSIONS

This paper proposes a framework to produce a

lightweight CP-ABE algorithm for IoT devices. The

proposed algorithm allows one message or ciphertext

placed in the cloud to be accessed by many IoT

devices as long as it meets the policy set in the access

policy. Expected output that will be obtained from

research analysis later is size decryption key and size

ciphertext that will not increase with the number of

user attribute. Besides the small size, it is also

constant. This is because the big challenge in CP-

ABE is to make sure attributes embedded in a private

key do not influence the size of keys, as well as

boolean in access policy will not affect the size of

ciphertext.

Figure 3: Four Algorithm in CP-ABE cryptography scheme

REFERENCES

Agarwal, M. 2015. "Role of IOT devices and servcies in

the development of smart cities." from

https://www.slideshare.net/mayankagarwal51/role-of-

iot-devices-and-servcies-in-the-development-of-smart-

cities.

Ambrosin, M., A. Anzanpour, M. Conti, T. Dargahi, S. R.

Moosavi, A. M. Rahmani and P. Liljeberg. 2016 "On

ICEST 2018 - 3rd International Conference of Computer, Environment, Agriculture, Social Science, Health Science, Engineering and

Technology

382

the feasibility of attribute-based encryption on internet

of things devices." IEEE Micro 36(6), 25-35.

Bethencourt, J., A. Sahai and B. Waters. 2007 "Ciphertext-

policy attribute-based encryption". IEEE Symposium on

Security and Privacy, IEEE.321-334

Cheung, L. and C. Newport. 2007 "Provably secure

ciphertext policy ABE". Proceedings of the 14th ACM

conference on Computer and communications security,

ACM.456-465

Delerablée, C. 2007 "Identity-based broadcast encryption

with constant size ciphertexts and private keys".

International Conference on the Theory and

Application of Cryptology and Information Security,

Springer.200-215

Emura, K., A. Miyaji, A. Nomura, K. Omote and M. Soshi.

2009 "A Ciphertext-Policy Attribute-Based Encryption

Scheme with Constant Ciphertext Length". ISPEC,

Springer.13-23

Guo, F., Y. Mu and W. Susilo. 2012 "Identity-Based Traitor

Tracing with Short Private Key and Short Ciphertext".

ESORICS, Springer.609-626

Guo, F., Y. Mu, W. Susilo, D. S. Wong and V.

Varadharajan. 2014 "CP-ABE with constant-size keys

for lightweight devices." IEEE Transactions on

Information Forensics and Security 9(5), 763-771.

Guo, H., C. Xu, Z. Li, Y. Yao and Y. Mu. 2013 "Efficient

and dynamic key management for multiple identities in

identity-based systems." Information Sciences 221,

579-590.

Herranz, J., F. Laguillaumie and C. Ràfols. 2010 "Constant

size ciphertexts in threshold attribute-based

encryption". International Workshop on Public Key

Cryptography, Springer.19-34

Katagi, M. and S. Moriai. 2008 "Lightweight cryptography

for the internet of things." Sony Corporation, 7-10.

Li, H., X. Lin, H. Yang, X. Liang, R. Lu and X. Shen. 2014

"EPPDR: an efficient privacy-preserving demand

response scheme with adaptive key evolution in smart

grid." IEEE Transactions on Parallel and Distributed

Systems 25(8), 2053-2064.

Liew, S.-C., Liew, S.-W., Zain, J.M. 2013. "Tamper

localization and lossless recovery watermarking

scheme with roi segmentation and multilevel

authentication". Journal of Digital Imaging, 26 (2), pp.

316-325.

Odelu, V., A. K. Das, M. K. Khan, K.-K. R. Choo and M.

Jo. 2017 "Expressive CP-ABE scheme for mobile

devices in IoT satisfying constant-size Keys and

ciphertexts." IEEE Access 5, 3273-3283.

Sahai, A. and B. Waters. 2005 "Fuzzy identity-based

encryption". Annual International Conference on the

Theory and Applications of Cryptographic Techniques,

Springer.457-473

Vaanchig, N., W. Chen and Z. Qin. 2016 "Ciphertext-

Policy Attribute-Based Access Control with Effective

User Revocation for Cloud Data Sharing System".

International Conference on Advanced Cloud and Big

Data (CBD), IEEE.186-193

Yang, Y., H. Cai, Z. Wei, H. Lu and K.-K. R. Choo.2016

"Towards Lightweight Anonymous Entity

Authentication for IoT Applications. Information

Security and Privacy": 21st Australasian Conference,

ACISP 2016, Melbourne, VIC, Australia, July 4-6,

2016, Proceedings, Part I. J. K. Liu and R. Steinfeld.

Cham, Springer International Publishing, 265-280.

Yuan, W. 2016 "Dynamic Policy Update for Ciphertext-

Policy Attribute-Based Encryption." IACR Cryptology

ePrint Archive, 457.

Zain, J.M. 2010 "Strict authentication watermarking with

JPEG compression (SAW-JPEG) for medical images".

European Journal of Scientific Research, 42 (2), pp.

232-241.

Zhang, Y., D. Zheng, X. Chen, J. Li and H. Li. 2014

"Computationally efficient ciphertext-policy attribute-

based encryption with constant-size ciphertexts".

International Conference on Provable Security,

Zheng, M., Y. Xiang and H. Zhou. 2015 "A strong provably

secure IBE scheme without bilinear map." Journal of

Computer and System Sciences 81(1), 125-131.

Conceptual Framework for Lightweight Ciphertext Policy-attribute based Encryption Scheme for Internet of Thing Devices

383