The

$[$Select$]$

ciphers are better used when the

size of the plaintext message is fixed or known in advance, while the

$[$Select$]$

ciphers are often better for use in cases

where the size of the plaintext message is either unknown, or the

message is continuous. By comparison, the block ciphers have

$[$Select$]$

speed and

error propagation than the stream

ciphers.