Cryptographic Techniques, Threats and Privacy Challenges in Cloud Computing Jissy Ann George 1 , Dr.M.Hemalatha 2 1 Research Scholar, Department of Computer Science, Karpagam University Coimbatore, India 2 Professor, Department of Computer Science, Karpagam University Coimbatore, India Abstract— Cryptography is essential for the security and integrity of the data that is stored in the cloud. Several cryptographic techniques are used to protect the integrity of data for various applications. A particular security method makes use of different cryptographic techniques to encrypt data and make it into an un-readable form, which can then be decrypted only with the help of a key. A number of cryptographic techniques are available for use in protection of data in various applications. Cryptographic techniques are essential for the confidentiality of the data saved. Cloud computing is used to share resource as service, software as service, infrastructure as service, platform as service to the clients. The use of cryptography in the cloud will enable the security of the data being shared. Confidentiality and integrity of data in data security are essential in the cloud. This paper presents an overview of the cryptographic techniques, security and privacy challenges related to public cloud computing. Keywords— Cloud computing, cryptographic techniques, domains, encryption, security issues, threats I. INTRODUCTION Privacy of data is of extreme need in this present time and cryptography plays a significant role. Security issues need to be addressed in various areas. At present there are a number of cryptographic algorithms which have been designed for the protection of data in various applications. Cryptography [1] refers to the science of designing ciphers, namely, block ciphers, stream ciphers and hash functions. Encryption refers to the method of converting ordinary text to a secret text to protect its integrity. There are primarily two categories of encryption algorithms [2] which are mainly: symmetric algorithms such as DES, AES, Triple DES and asymmetric or public-key encryption algorithms such as RSA, Diffie-Hellman, ECC, etc. The difference is in the way the keys are used. In symmetric key encryption, the person who is sending the data and the person who is receiving the data share a key which is kept secret. This is then used to encrypt and decrypt the messages. In asymmetric key encryption, two keys are involved wherein one is used for encryption (this is publicly available) and the other is used for decryption (this is kept secret). Cloud Computing is very popular as many companies are now into cloud platforms. A major barrier for cloud adoption is lack of security. Cloud computing security is vulnerable to many issues such as virtualization infrastructure; software platform; identity management and access control; data integrity; confidentiality and privacy; physical and process security aspects; and legal compliance in cloud. Important research directions in cloud security in areas such as Trusted Computing, Information Centric Security and Privacy Preserving Models [3]. Cloud computing enables organizations and individuals to work from anywhere in the world on demand. Cloud computing enables appropriate, on-demand network access to computing resources such as infrastructure, applications and services [4]. Cloud computing can be employed under many models, used in various architectures. The use of cryptography is very important for the maintenance of security in the cloud. This paper gives a comparative analysis of the several cryptographic techniques utilized in the security process of the cloud. It also addresses the various security issues and domains in the cloud computing environment. There are many cryptographic techniques that have been in use for security in the cloud. This article reviews some of the techniques that have been used in the cloud environment. It gives a mapping of the top nine threats faced in the cloud and the security domains in which these fall into. The paper initially discusses the various security issues and threats in the cloud. An overview of the various cryptographic techniques is presented next. Using the mapping as a reference, various controls can be applied to the threats with the use of the cryptographic techniques that have been used. Finally, possible enhancements that can be done in this area are suggested. II. PRIVACY CHALLENGES, SECURITY DOMAINS AND TOP THREATS IN THE CLOUD The privacy challenges in public cloud are namely: lack of user control, potential unauthorized secondary usage, data proliferation, trans border data flow, dynamic provisioning, retention of data, ensuring data has been lost, privacy breaches [5]. Security challenges would include access, control over data lifecycle, availability and backup, lack of standardization, multi-tenancy and audit. Trust challenges [6] are weak trust relationships and lack of customer trust. The different security issues were also classified into levels [7] that exist in cloud environments. Different solutions were provided to deal with the security issues in the cloud as per the type of security provided. Software policies to allow clients to use the security means they need at the levels where the issues happen. Cloud security was grouped into a model comprised of seven categories [8] which were network security, interfaces, data security, virtualization, governance, Jissy Ann George et al, / (IJCSIT) International Journal of Computer Science and Information Technologies, Vol. 6 (2) , 2015, 1080-1083 www.ijcsit.com 1080