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Types of` Symmetric Ciphers

Stream ciphers

In a stream cipher the plaintext digits are encrypted one at a time, and the transformation of successive digits varies during the encryption. In practice, the digits are typically single bits or bytes. It is a symmetric key cipher where plaintext bits are combined with a pseudorandom cipher bit stream (keystream), typically by an exclusive-or (xor) operation. These are more suitable for hardware implementations. Stream ciphers can be designed to be exceptionally fast, much faster than any block cipher.

Characteristics of a strong and effective cipher algorithm include:

Block ciphers

It is a symmetric key cipher operating on fixed-length groups of bits, termed as blocks. Common block sizes are 64 and 128 bits.  Encryption takes place under the action of a user-provided secret key. Decryption is performed by applying the reverse transformation to the ciphertext block using the same secret key.
When we use a block cipher to encrypt a message of arbitrary length, we use techniques known as modes of operation for the block cipher. The standard modes are Electronic Code Book (ECB), Cipher Block Chaining (CBC), Cipher Feedback (CFB), and Output Feedback (OFB).