In this paper, we proposed a novel triple algorithm based on RSA (Rivest-Shamir-Adleman), AES (Advanced Encryption Standard), and TwoFish in order to further improve the security of Bluetooth that is currently using only 128-bit AES for encryption in its latest versions (Bluetooth 4.0 - 5.0). Further-more, older Bluetooth 1.0A – 3.0 + HS (High-Speed) devices use E0 stream cipher for encryption that has been shown to be weak by numerous researchers and thus it could be considered insufficient for high security purposes nowadays. In our novel approach, the triple protection of AES, RSA, and TWOFISH would enhance the level of security, which shields the data transmission in the Bluetooth. As the first step of our novel approach, we first encrypted the message by using AES with 128-bit key and then further encrypted it by using Twofish with the same 128-bit key. Finally, the 128-bit key generated in the beginning will be encrypted by using RSA with 1024-bit key to protect its over-the-air transfer. In the receiving end, the decryption process goes in reverse order compared with encryption process. We showed with experimental figures that our novel algorithm improved the security of Bluetooth encryption by eliminating all known weaknesses and thus made data exchange between Bluetooth devices secure.
Bluetooth [
Several kinds of Bluetooth devices are used globally. In fact, in 2006, the number of shipped devices reached to one-billionth devices [
As Bluetooth is growing in popularity and it adopts rapidly spreading all around the world, the security of this network is a major source of concern as several threats exist to exploit the vulnerabilities found in this network. Data transmission over Bluetooth network is always at risk of being compromised, as sensitive information and documents are been transmitted over Bluetooth network. Bluetooth being a wireless network can be spied upon from a remote location which may have serious consequences on the integrity of the data being transmitted or the network to which it’s being connected. E0 stream cipher is being currently utilized for data encryption in Bluetooth technology; however, there are few weaknesses found in 128-bit E0 stream cipher implementation, and it can be easily cracked, in some cases by 0 (264) mode [
Our results: In this paper, we propose a hybrid encryption algorithm to securely communicate in Bluetooth network based on the combination of AES, RSA and Twofish. We demonstrate with experimental figures the effectiveness of this proposed algorithm to protect the confidentiality and integrity of messages transmitted over the Bluetooth network by encrypting the message first with AES Key 128 bits, and then with Twofish and RSA. Our results show that this hybrid algorithm will increase the security level of the encryption mechanism in Bluetooth communications and thus the confidentiality of messages transmitted over the network will be guaranteed.
The rest of the paper is organized as follows. Section 2 provides an overview of Bluetooth security. Our novel secure data transmission technique is proposed in Section 3. Section 4 provides our experimental results and analysis. Finally, Section 5 concludes the paper.
In this section we will discuss about the three unique algorithms we implemented in our proposed technique. Sub-section 2.1 discusses about AES, Sub-section 2.2 discusses about Twofish and Sub-section 2.3 discusses about RSA.
AES was introduced by NIST in 2001 to replace DES. The AES algorithm is a symmetric block cipher used to protect important documents by the US government and implemented for data encryption all around the word [
Twofish algorithm is a symmetric block cipher which has fiestel like structure [
RSA algorithm is an asymmetric key cryptographic algorithm; it was invented in 1977 by Ron Rivest, Adi Shamir and Len Adlemen. It uses the concept of two keys; the public and the private key; RSA algorithm converts the plaintext into a ciphertext by encrypting the message using the public key, which only the receiver can decrypt with the use of a private key. RSA algorithm’s invention is base on the arithmetical concept that it is easy to find and multiply large prime numbers but to factor their product is difficult. Both private key and public keys in RSA algorithm are based on prime numbers that are large (100 or more digits) [
The steps below explain RSA algorithm in details [
1) Two prime number p and q are chosen
n = p × q
where n represents a large integer whose factorization produce two large prime number p and q.
2) n = ( p − 1 ) × ( q − 1 )
3) The encryption key is randomly selected
where 1 < e < ϕ ( n ) , gcd ( e , ϕ ( n ) ) = 1 .
4) The following equation is solved to compute decryption key d
d e = 1 mod ϕ ( n ) and 0 ≤ d ≤ n .
5) public key PU = e, n.
6) private key PR = d, n.
Information security in the network has been a challenge, which demands urgent attention. Notably with the rapid development of computer technology, several issues arose to the surface of the Information Security field such as User Authentication, data encryption, data integrity, and access control. Bluetooth is a radio communication standard short-range, which enables electronic devices to be connected as well as communicated wirelessly. Also, Bluetooth functions in the frequency band the 2.4 Hz. It uses FHSS (Frequency Hopping Spread Spectrum) because it makes eavesdropping becomes tough. Frequency Hopping Spread Spectrum, which is a radio transmission process where randomly, chosen frequencies hopping between 79 different frequencies at regular intervals in accordance with a pseudorandom sequence. Further, the transmission range is up to 10 meters, and data can be transmitted over asynchronous (ACL Asynchronous Connection Less) or synchronous channels (SCO, Synchronous Connection-Oriented). In earlier versions of Bluetooth, an E0 stream cipher algorithm is used for encryption process. However, this algorithm has proven to be vulnerable [
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The authors in this paper show a comparison between the RSA public key-based algorithm and DES private key based Algorithm. They found that the central feature that differentiate RSA public key-based algorithm from DES private key based Algorithm was related to the input plain text speed during the encryption and decryption process. Moreover, the authors reported that the time consumed of execution both decryption and encryption process of RSA algorithm is least as compared to DES algorithm. Noteworthy, DES algorithm has a faster speed during encryption and decryption than RSA algorithm [
The primary concern of this study is to highlight the weakness of the Bluetooth encryption mechanism and provide a solution. As the aim is pointed towards the interpretation of flaws in the preceding design, Bluetooth E0 algorithm is suffered from a numerous number of attacks and it is proven that E0 algorithm could be broken in 264 operations [
As the issue is correlated with the security of the data transmitted via Bluetooth communication, we invariably strive to produce a reliable algorithm for securing data. In this section, we will explain the novel algorithm and the experiment along with the results thoroughly. The reason for employing RSA is that the key management is a primary feature. In addition, the method applied in RSA is relied on the difficulty of factoring large numbers. For AES, it gives a great performance and it is robust as well as efficient. Finally, Twofish comes to be chosen because of its unique combination of conservative design, flexibility and speed. Noteworthy, it is strong and conceptually simple.
First plaintext is encrypted with AES and we get a cipher text then again cipher text encrypted with Twofish algorithm. Finally, we get a complex encryption value against plain text passing through two time encryption algorithms.
During the decryption of the hybrid encryption algorithm, the process is the reverse of the encryption process (see
Our proposed hybrid algorithm was successfully implemented, in which we clearly demonstrated the effectiveness of this hybrid technique in efficiently securing the transmission of data and it has shown to be a stronger information security technique for data communications. The combination of AES, Twofish and RSA encryption algorithm formed a strong secured protocol that has increased the security of Bluetooth communication against any known attacks.
Our result is depicted with
Bluetooth is an inspiring innovative technology, which revolutionizes the way we communicate. However, the security mechanism of earlier versions Bluetooth technology has not been equipped with adequate level of security. Thus, it is more vulnerable to different attacks. Even though the current security mechanism of the latest versions (4.0 - 5.0 v) has been provided an acceptable level of security, however, a high level of security is paramount. In light of this paper, the proposed method was feasible as well as successfully implemented, and it is utilized in live scenarios. In the context of the feasibility of our approach, because the high level of security provided the encryption key remains secret, the original message remains safe. In case of intrusion, the organization of the complex message is intricate, which confused the intruder in understanding which part of the complex message contains the ciphertext and encrypted key. Moreover, the private key of the receiver will not be known. Therefore, the process of transmission data remains secure due to the unique security combination provided by our novel triple algorithm. Indeed, the proposed method has improved the security of encryption algorithm in Bluetooth. In the future, we plan to further develop new ideas concerning the Bluetooth security. First, we plan to analyze the current encryption mechanism weakness, after which we will propose a proper solution. Second, we will propose a geographic pairing based protocol, which will offer resistance against several attacks and add another authentication factor to the pairing process in order to present a strong authentication approach during the Bluetooth pairing process. Positively, these contributions will supply an extra security layer to achieve a high level of security.
Albahar, M.A., Olawumi, O., Haataja, K. and Toivanen, P. (2018) Novel Hybrid Encryption Algorithm Based on Aes, RSA, and Twofish for Bluetooth Encryption. Journal of Information Security, 9, 168-176. https://doi.org/10.4236/jis.2018.92012