a **hash** **function** which resists second preimage attacks (like MD5 [21]; namely: collision resistance is no longer required) and a commitment scheme. Other so- lutions such as MANA protocols [13,14] have been proposed. They can reduce the amount of information to be authenticated down to 20 bits, but they work as- suming a stronger hypothesis on the authenticated channel, namely that the au- thentication occurs without any latency for the delivery. Some protocols based on the Diffie-Hellman one were proposed [11,15] with an incomplete security analysis. A provably **secure** solution was finally proposed by Vaudenay [22]. This protocol can work with only 20 bits to authenticate and is based on a com- mitment scheme. Those authentication protocols can be pretty cheap (namely: without public-**key** **cryptography**) and provably **secure** (at least in the random oracle model). So, the remaining overwhelming cost is still the Diffie-Hellman protocol. Since **key** agreement is the foundation to public-**key** **cryptography**, it seems that setting up **secure** communications with an authenticated channel only cannot be solved at a lower expense than regular public-**key** algorithms.

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Abstract—Due to the recent innovations in the internet and the network applications and the wide spread of internet and networks, it is now completely possible to conduct electronic commerce on the internet or through the local area networks, and the wide spread of computer and communication network promoted many users to transfer files and sensitive information through the network, this sensitive data requires special deal. This work presents a security system that can provides privacy and integrity for exchanging sensitive information through the internet or the communication networks, based on the use of recently developed encryption algorithms, such as AES, IDEA and RSA. The aim of the work is to develop a simple file transfer system that can obtains privacy, integrity and authentication for the file transfer process. The proposed system uses **symmetric** **cryptography** system for securing file transfer while **using** public **key** cryptosystem and one way **hash** **function** to provide integrity, authentication and **key** distribution. The system is developed while putting into consideration the optimization of the communication channel and the speed of the encryption process.

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Abstract— This paper is presenting **cryptography** model of block based cipher technique. This model is divided into two sub model one is encryption model and other is decryption model. **Using** encryption model, encrypt any type of data like text, image, pdf, audio. **Using** decryption model, decrypt same data. Due to the simplicity of the proposed model, it is very efficient. This model is also much secured due to **key** length which is used at the time of encryption and decryption. The Proposed model is **using** 256 **key** lengths. The proposed model applied the basic computing operations to design model in this study. The Proposed model used the inserting dummy symbols, XOR, Shifting like right circular shift and left circular shift and inserting control byte to build the data in the proposed model of encryption and decryption. These operations are simple and easily to implement. Without knowing the data, it is difficult to do cryptanalysis. In the decryption model, it used these data to decrypt cipher text to plaintext. The Proposed model easily applies these two models to transmit data in network and the data transmission is **secure**.

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IT-related capabilities are provided as services to multiple external customer through Cloud Computing **using** internet technology. The use of the Internet and new technologies nowadays, for business and for the current users, is already part of everyday life. It allows users to consume services without knowledge and control technology and infrastructure supporting them. To days’ businesses are very complicated, whenever there is a new requirement we need to purchase new hardware, software licenses etc. organizations also need experts to install, configure, test and run them. Cloud computing reduces this entire burden as organizations need not to own all these resources. Resources are owned by the third party cloud provider. The basic idea behind this is reusability of IT resources. Services are provided as utility in cloud computing so user only pay according to the type and amount of service they used. Beside all the advantages of cloud since it is a distributed and shared environment there are several issues related to its security. One of them is Authentication that must be solved in Cloud computing environment as soon as possible. Therefore, we wishes to propose protocol that can solve suitable user and services

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Abstract: Security is a critical challenge for the effective expansion of all new emerging applications in the Internet of Things paradigm. Therefore, it is necessary to define and implement different mechanisms for guaranteeing security and privacy of data interchanged within the multiple wireless sensor networks being part of the Internet of Things. However, in this context, low power and low area are required, limiting the resources available for security and thus hindering the implementation of adequate security protocols. Group keys can save resources and communications bandwidth, but should be combined with public **key** **cryptography** to be really **secure**. In this paper, a compact and unified co-processor for enabling Elliptic Curve **Cryptography** along to Advanced Encryption Standard with low area requirements and Group-**Key** support is presented. The designed co-processor allows securing wireless sensor networks with independence of the communications protocols used. With an area occupancy of only 2101 LUTs over Spartan 6 devices from Xilinx, it requires 15% less area while achieving near 490% better performance when compared to cryptoprocessors with similar features in the literature.

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In the paper, we will organize the rest as follows. In Section 2, we will introduce the **function** of positioning protocols and one **secure** positioning protocol. In Section 3, one model and the definition of positioning-protocol-based **symmetric** **cryptography** are provided. We will propose one positioning-protocol-based **symmetric** cryptographic scheme in Section 4. Its correctness is proved in Section 5. The security of the proposed scheme will be briefly analyzed in Section 6. Finally, the conclusion is given.

Rivest,Shamir and Adelman introduces RSA. RSA is a form of public **key** **cryptography**. The public **key** **cryptography** creates its public and secret **key** with the following procedure. RSA is the most commonly standards of encryption in computer world. The RSA is most widely used in web browser such as net space to email encryption programs. The security is based on integrated factorization problem (IFP). They use large integers (1024 bites). The main importance of RSA, it was not been proven that breaking RSA algorithm is equal to factoring large number but neither has it been proven the factorization is not equivalent. The different types of attacks on RSA such as searching the massage space, guessing private **key** , cycle attack , common modular, low exponent, and final factoring variable N which is factoring the public **key** and it‟s the best way to crack RSA. In enhanced form of RSA we will going to add one more objective with p and q, the third objective will be r.

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RSA: The first, and still most common, PKC implementation, named for the three MIT mathematicians who developed it Ronald Rivest, Adi Shamir, and Leonard Adleman. RSA today is used in hundreds of software products and can be used for **key** exchange, digital signatures, or encryption of small blocks of data. RSA uses a variable size encryption block and a variable size **key**. The **key**-pair is derived from a very large number, n, that is the product of two prime numbers chosen according to special rules; these primes may be 100 or more digits in length each, yielding an n with roughly twice as many digits as the prime factors. The public **key** information includes n and a derivative of one of the factors of n; an attacker cannot determine the prime factors of n and, therefore, the private **key** from this information alone and that is what makes the RSA algorithm so **secure**. Some descriptions of PKC erroneously state that RSA's safety is due to the difficulty in factoring large prime numbers. In fact, large prime numbers, like small prime numbers, only have two factors. The ability for computers to factor large numbers, and therefore attack schemes such as RSA, is rapidly improving and systems today can find the prime factors of numbers with more than 200 digits. Nevertheless, if a large number is created from two prime factors that are roughly the same size, there is no known factorization algorithm that will solve the problem in a reasonable amount of time; a 2005 test to factor a 200-digit number took 1.5 years and over 50 years of compute time. Regardless, one presumed protection of RSA is that users can easily increase the **key** size to always stay ahead of the computer processing curve. As an aside, the patent for RSA expired in September 2000 which does not appear to have affected RSA's popularity one way or the other.

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main purpose of the **cryptography** is not to only provide confidentiality, but also to give solutions for other problems like: Integrity of data, authentication and non-repudiation. **Cryptography** is the method that allows information to be sent in a **secure** form in such a way that the only receiver is able to retrieve this information. Presently continuous researches on the new cryptographic algorithms are going on. However, it is very difficult to find out the specific algorithm, because they must consider many factors like: security, the features of algorithm, the time complexity and space complexity. Figure 1 is representing conventional encryption model.

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In the present paper the authors have introduced a new updated two-way generalized vernam cipher method called TTSJA. Chatterjee et.al developed a method [1] where they used three independent methods such as MSA [2], NJJSAA [3] and modified generalized vernam cipher method. Nath et al already developed some **symmetric** **key** methods [2,3,4,5] where they have used bit manipulation method and some randomized **key** matrix for encryption and decryption purpose. In the present work the authors have used updated generalized vernam cipher method in two directions. One from first character to last character and then we perform vernam method with XOR operation from last to first We found the results are quite satisfactory even for short message and repeated characters also. The advantage of the present method is that the overhead is minimum but the encryption is very hard. This method may be applied to encrypt short message such as SMS, password, ATM code etc. In the present work the authors have introduced updated Vernam Cipher method. The authors modified the standard Vernam Cipher method for all characters (ASCII code 0-255) with randomized keypad and also introduced feedback. After first phase encryption the modified vernam cipher method applied from last character to the first **using** random keypad and feedback. In the second phase instead of adding the keypad ASCII the authors performed the XOR with keypad and the encrypted text (after first phase). This method closely monitored on different known plain text and it was found that this method is almost unbreakable. The present method allows the multiple encryption and multiple decryption. To initiate the encryption process a user has to enter a text-**key** which may be maximum of 16 characters long. From the text- **key** the randomization number and the encryption number is calculated **using** a method proposed by Nath et al [2]. A minor change in the text-**key** will change the randomization number and the encryption number quite a lot. The present method is a block cipher method and it can be applied to encrypt confidential data in Defense system, Banking sector, mobile network, Short message Service, Password, ATM **key** etc. The advantage of the present method is that one can apply this method on top of any other standard algorithm such

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Encryption algorithm plays an imperative task for information security guarantee in recent mounting internet and network application. In this paper, we studied two **symmetric** **key** encryption algorithms: AES and BLOWFISH. We assessed encryption speed, throughput and power burning up for their performance. The simulation results showed that Blowfish has superior performance than AES since Blowfish has not any known security weak points so far, it can be considered as an excellent standard encryption algorithm. BLOWFISH algorithm sprints faster than AES and showed poor performance results compared to BLOWFISH algorithms since it requires more processing power. Thus Blowfish algorithm maybe more appropriate for wireless set-up which swaps small size packets.

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In AES-CBC encryption, the first input block is formed by XOR the first block of the plaintext with IV. The AES cipher **function** is applied to each input block to produce the ciphertext block (output block). With CBC mode, an XOR is performed on the input plaintext and the previously ciphertext block (output block). Since previously encrypted data is not available for the first operation an initialization vector (IV) must be provided. CBC works on complete 128-bits blocks of plaintext. In AES-CBC decryption, the AES inverse cipher **function** is applied to the first ciphertext block, and the resulting output block is XOR with the IV to recover the first plaintext block. In general, to recover any plaintext block (except the first), the AES inverse cipher **function** is applied to the corresponding ciphertext block, and the resulting block is XOR with the previous ciphertext block as shown in (Figure 4).

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Data storage correctness scheme classified in two categories (a) without use of third party auditor (Non TPA) (b) With use of third party auditor (TPA).In case of **using** TPA, an external Third Party Auditor (TPA) that verifies the data integrity and se nds report to user, some time in form of extra hardware or cryptographic coprocessor is required. This hardware scheme provides better performance due to dedicated hardware for the auditing process but has some drawbacks

Signature: code hash of message using private key PKCS-1: standard encrypt using secret key. 0||1||at least 8 byte FF base 16|| 0|| specification of used hash function || hash(M)[r]

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An important and unique property of quantum **cryptography** is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the **key**. These results from a fundamental part of quantum mechanics: the process of measuring a quantum system in general disturbs the system. A third party trying to eavesdrop on the **key** must in some way measure it, thus introducing detectable anomalies. By **using** quantum superposition or quantum entanglement and transmitting information in quantum states, a communication system can be implemented which detects eavesdropping. If the level of eavesdropping is below a certain threshold a **key** can be produced which is guaranteed as **secure** (i.e. the eavesdropper has no information about), otherwise no **secure** **key** is possible and communication is aborted.

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Abstract: In this work we study the energy consumption by various modern secured **hash** functions (MD2, MD5, SHA-1, and SHA-2) and modern **symmetric** **key** encryption protocols (Blowfish, DES, 3DES, and AES) from the algorithmic perspective. We identify various parameters that moderate energy consumption of these hashes and protocols. Our work is directed towards redesigning or modifying these algorithms to make them consume lesser energy. As a first step, we try to determine the applicability of the asymptotic energy complexity model by Roy et. al. on these hashes and protocols. Specifically, we try to observe whether parallelizing the access of blocks of data in these algorithms reduces their energy consumption based on the energy model. Our results confirm the applicability of the energy model on these hashes and protocols. Our work is motivated by the relevance and importance of cryptographic hashes and **symmetric** **key** protocols for modern ICT (Information and Communication Technology), and ICT enabled industry to keep them protected from dynamically changing threat scenarios. Hence the design of more energy efficient hashes and protocols will definitely contribute in reducing the ICT energy consumption that is continuously increasing.

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A. Data Encryption Standard (DES): DES is the most widely used **symmetric** cipher. It was designed by IBM based on their Lucifer Cipher. DES is a 64 bit block cipher which means that it encrypts data 64 bits at a time. DES is based on a cipher known as the Feistel block cipher. This was a block cipher developed by the IBM **cryptography** researcher Horst Feistel in the early 70’s. As with most encryption schemes, DES expects two inputs - the plaintext to be encrypted and the secret **key**. It consists of a number of rounds where each round contains bit-shuffling, non-linear substitutions (S-boxes) and exclusive OR operations. Initially, 56 bits of the **key** are selected from the initial 64 by permuted choice. The remaining eight bits are either discarded or used as parity check bits. The 56 bits are then divided into two 28-bit halves; each half is thereafter treated separately. In successive rounds, both halves are rotated left by one or two bits and then 48 sub **key** bits are selected by permuted choice(2),24 bits from the left half and 24 from the right. The **key** schedule for decryption is similar, the sub keys are in reverse order compared to encryption.

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The parameters we select directly affect the area and performance of the crypto engine. Typically, to reduce the area, lightweight cryptographic systems utilize shorter keys (80-bits). In our design, we aim to find the best configuration that will at least meet this security level while minimizing the area. We utilize SIMON 96/96 for **symmetric** **key** encryption and PRNG, and SIMON 96/144 for hashing. One of the challenges in selecting the parameters of the crypto engine is to satisfy the security needs of the **hash** **function**. The security level of a **hash** is determined by the size of the output digest and the probability of a collision on the value of a digest. We choose the most stringent security constraint of strong collision resistance [27] which requires that a **hash** at a k-bit security level provides a 2k-bit digest. A common practice in building **hash** functions is to use a block cipher with single-block-length (SBL) constructions like Davies- Meyer [35] or double-block-length (DBL) constructions like Hirose [20]. In SBL, the output size of the **hash** **function** is equal to the block size of the underlying block cipher, while in DBL it is twice the block size. To have a strong collision resistance of minimum 80-bits in SBL, the underlying block cipher must have a block size of at least 160-bits. On the other hand, DBL can achieve the same level of security with a block size of only 80-bits.

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