The lack of data security in public mobile telecommunication system increases the need for a strong data protection and security mechanisms.

Nowadays, cloud computing has experienced remarkable growth. Indeed, one of the main challenges of cloud computing is to protect data from different sensor devices during processing and storing. In 2014, Henze et al. proposed the Sensor Cloud Security library (SCSlib) which allows cloud developer to access encrypted sensor data stored in the cloud. SCSLib drawback is that it allows a dishonest referee, dealing with a dispute, to decrypt all the future and past authenticated cipher-text between parties. In this study, we proposed an improved scheme for the SCSlib that prevent the users of the library from such attacks. In addition, the proposed scheme fulfils the following security requirements: Integrity, authenticity, confidentiality and availability. Moreover, security analysis in the cloudcomputing environment is presented.

Cryptography offers effective techniques to ensure users' security and privacy in an efficient way. To protect networks from intruders/attackers and transmit a message over an insecure channel, encryption and digital signature algorithms could be used within different designs to provide secure networks and security solutions in order to protect users' information and their data from being attacked. These designs would ensure confidentiality, authenticity, integrity, and non-repudiation. Signcryption algorithms achieve the properties of both digital signature and encryption schemes. In this paper, we implement the Schnorr Signcryption and RSA Encrypt-Sign-Encrypt (Sign-Encrypt-Sign) schemes. Moreover, we will illustrate the comparison between the RSA Encrypt-Sign-Encrypt and Schnorr Signcryption schemes in terms of computation cost. Additionally, we will present an improvement factor in the case of parallelisation techniques applied to Schnorr Signcryption and RSA Encrypt-Sign-Encrypt (Sign-Encrypt-Sign) schemes.