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Quantum Cryptography and Teleportation
Published in F.J. Duarte, Quantum Optics for Engineers, 2017
Albeit still in use, classical paper-based code systems have been largely replaced by various computerized mathematical methods that enable the electronic transmission of encrypted messages. The message is encrypted prior to transmission, transmitted via an unsecured channel in encrypted form, and decoded, once received. A widely used system of encryption, of this class, is known as symmetric key algorithm. This approach utilizes the same cryptographic key, or classical algorithm, for encryption and decryption (see Figure 19.2).
Security algorithms for secure cloud environment
Published in Muhammad Imran Tariq, Valentina Emilia Balas, Shahzadi Tayyaba, Security and Privacy Trends in Cloud Computing and Big Data, 2022
Maryam Saleem, Maryam Rasheed, Muhammad Imran Tariq, Shahzadi Tayyaba, Muhammad Arfan Jaffar
Since it belongs to the first group of encryption algorithms known as symmetric, DES encrypts and decrypts data with only one key. The main goal of this algorithm is to ensure data protection. The plain text is used first, followed by the 64 bits of data divided into two halves. Then the data of 56 bits are decreased with 48 bits. Then the output of one side is applied on the second side with XOR operation. And at the end, the ciphertext is generated. AES is also a symmetric key algorithm. First of all, for performing the encryption process, the plain text is taken, then a round key is used that contains further four keys. The keys are Substitution key, Shift Rows key, Column mixing key and add round keys. But the last cycle does not contain the Mix columns key. So, encryption is performed and for performing the decryption process the whole ciphertext is given to the next round. This round also contains four keys. In this way, the decryption process is generated and the plain text is available. 3DES performs a similar operation just like DES algorithm. But 3DES works by using DES algorithm for three times, so 3DES is considered slower than DES algorithm. It uses 168 bits because the DES is used as three times. So, it provides more security than DES algorithm. Blowfish contains 16 rounds just like DES but it is faster than DES. So, it provides more security on data. RSA is an asymmetric key algorithm that works with two different keys. Public and Private keys are used in the RSA algorithm. The public key is available to everyone and can be easily shown to the entire public, but the private key is not shown to the public. It has many faults so it is not secure for some applications. And it is a slow algorithm. Diffie-Hellman is used for the communication between two people, but its security breaks down in the middle of the communication. So, it shows that the AES algorithm is better and strong as compared to other algorithms [30,31].
Proxy re-encryption architect for storing and sharing of cloud contents
Published in International Journal of Parallel, Emergent and Distributed Systems, 2020
Symmetric-key algorithm – the same key is used for encryption/decryption. Key distribution has to be made before information transmission. Key security is very important for keeping information safe. Various algorithms use different methods. They differ in complexity, but in general, the longer the key – the longer it takes to decrypt a message. The US National Institute of Standards and Technology recommend [28].