Hence, the current encryption box is not only dependent on the current plain text but also on the result of the former block. While encryption of a block, along with the key the encryption result of the previous block is also fed to the current encryption. To establish this, a method of chaining is done here. Hence, ECB is preferred for small plain texts with fewer or no repetitive characters.Ĭipher Block Chaining Mode − to overcome the problem of repetitive texts in ECB, CBC was developed which produces new cipher texts every time for identical blocks. That is, if there are two identical blocks, the process will not produce two different cipher texts for them. In the encryption process, since the same key was used, it always produces the same result for a single character. These blocks are decrypted separately with the help of the same key for all the blocks. After encryption, the blocks of cipher text are sent to the receiver which goes through a decryption process to decode the plain text.
Each of the blocks separately goes through encryption with the help of the same key.
Cipher key 64 bits#
The modes are as follows −Įlectronic Code Book Mode − in this type of operation, the plain text is divided into multiple blocks of 64 bits each.
There are 5 modes of operation of block cipher so that algorithm can be improved and a wider range of applications can be achieved. It is a reversible function having a public and a private key, which makes its computation easy and also a deterministic process. But if there are two identical blocks, the process will produce two different cipher texts for them. This type of encryption process considered each block at a time and gives an output of n bits for an input of n bits. In block ciphers, the length of the plain text is equal to the length of the cipher text. His type of encryption method can encrypt on blocks of 128 bits, the key can be 128, 192, or 256 bits. If the length of the plain text does not allow block division of equal size, padding is done over the plain text. The plain text is divided into several blocks of equal size. Block Cipher is an encryption algorithm that works with a symmetric key in a deterministic way.
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