Please explain the relationship between keys and algorithms

Please explain the relationship between keys and algorithms (ciphers). Which one is more important to keep a secret? Why?

Solution

Cipher algorithm is a step by step process for encrypting and decrypting messages/text and the acheive this step by step process, this operation requires and depends on a specific element called key.Its selected before using a cipher to encrypt a message.

The basic idea is to keep the key secret as without key it would be impossible to decrypt the message and that is our whole purpose of encrypting, to safely sends the messgae over network without any unintended audience to read it.