Merits and De-merits of secret key encryption

Question

State the merits and de-merits of the secret key encryption?

Answer 1

Merit:

Secret Key algorithms are proficient: it utilizes less time for encrypting the message. The reason is that the key is generally smaller. So it is utilized to encrypt or decrypt the long messages.

De-merit:

a) Each pair of users should have the secret key. If N people in the world want to use this method, there required to be N (N-1)/2 secret keys. For one million people to communicate, the half-billion secret keys are required.

b) The allocation of keys between two parties may be difficult.