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Informally, a message authentication code system consists of three algorithms: A key generation algorithm selects a key from the key space uniformly at random. A MAC generation algorithm efficiently returns a tag given the key and the message. A verifying algorithm efficiently verifies the authenticity of the message given the same key and the tag.
Authenticated Encryption (AE) is an encryption scheme which simultaneously assures the data confidentiality (also known as privacy: the encrypted message is impossible to understand without the knowledge of a secret key [1]) and authenticity (in other words, it is unforgeable: [2] the encrypted message includes an authentication tag that the sender can calculate only while possessing the ...
For example, SHA-256 operates on 512-bit blocks. The size of the output of HMAC is the same as that of the underlying hash function (e.g., 256 and 512 bits in the case of SHA-256 and SHA3-512, respectively), although it can be truncated if desired. HMAC does not encrypt the message.
All algorithms support authenticated encryption with plaintext P and additional authenticated data A (that remains unencrypted). The encryption input also includes a public nonce N, the output - authentication tag T, size of the ciphertext C is the same as that of P. The decryption uses N, A, C, and T as inputs and produces either P or signals ...
Because asymmetric key algorithms are nearly always much more computationally intensive than symmetric ones, it is common to use a public/private asymmetric key-exchange algorithm to encrypt and exchange a symmetric key, which is then used by symmetric-key cryptography to transmit data using the now-shared symmetric key for a symmetric key ...
The Lightweight Encryption Algorithm (also known as LEA) is a 128-bit block cipher developed by South Korea in 2013 to provide confidentiality in high-speed environments such as big data and cloud computing, as well as lightweight environments such as IoT devices and mobile devices. [1] LEA has three different key lengths: 128, 192, and 256 bits.
The key length is a multiple of n by 2, 3, or 4, which is the value m. Therefore, a Simon cipher implementation is denoted as Simon2 n / nm . For example, Simon64/128 refers to the cipher operating on a 64-bit plaintext block ( n = 32) that uses a 128-bit key. [ 1 ]
For example, encryption using an oversimplified three-round cipher can be written as = ((())), where C is the ciphertext and P is the plaintext. Typically, rounds R 1 , R 2 , . . . {\displaystyle R_{1},R_{2},...} are implemented using the same function, parameterized by the round constant and, for block ciphers , the round key from the key ...