Steam cipher is a method of encryption in which plain digits are combined with the pseudo-random stream to generate ciphertext one bit at a time. It operates on small plaintext units. It requires less code. It is used only once. It is used for hardware implementation and it is used within the Secure Sockets Layer (SSL).  A Block cipher is a method of encryption where a cryptographic key and algorithm are implemented to a block of data, like a group, in order to generate the ciphertext. It works on large data blocks. It is used to encrypt files and databases. It requires more code. Reuse of key is possible. It is used for file and database encryption. It is used to implement software.