Shulou(Shulou.com)06/01 Report--

What is the block cipher? Grouping, as its name implies, is to encrypt plaintext messages into groups, that is, the encrypter can only process a set of data of a specific length at a time, and the "set of data" here is called a packet. We also call the number of bits of each packet as the packet length.

After reading the explanation of the block cipher, you can see whether the cipher of the stream cipher and the cipher of the block cipher contain the explanation of memory element: for the block cipher, it ends an encryption process after processing a group. so there is no need to record the progress of encryption through the internal state On the contrary, for stream ciphers, it is a continuous encryption of a data stream, so the memory elements in it need to be encrypted to record the internal state of the cipher.

Block password:

Block cipher, which is the number sequence x0, x1, … Xi,... And divide it into groups x = (x0, x1, … , xn-1), each packet of length n has the key k = (K0, K1, … Under the control of kt-1), it is transformed into an equal-length output digital sequence y = (y0, y1, … , ym-1), whose encryption functions E: Vn × K → Vm,Vn and Vm are n-dimensional vector space and m-dimensional vector space respectively, and K is the key space.

As can be seen in the figure, enter a plaintext packet of length n, and output a ciphertext of length m after passing through the cipher. But in general, we take mencrypn, and if we encounter n > m, it shows that there is data compression in data encryption.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.