Why is it important for a cipher to have a large number of potential keys?

Question

Why is it important for a cipher to have a large number of potential keys?

Answer 1

A key is used to encrypt clear text into a cipher using a cryptographic system.  Ideally you would want just one(requires key exchange)  or two keys (public and private) which will enable the cipher to be decrypted into clear text (readable). It is desirable for the cryptographic system

to have many keys but NOT the cipher.

If you have a cipher(the encoded text) with many keys then you have more ways to decode it. This is like having a lock that allows many different keys to open it. A large number of keys degrades the security of the lock. The same is true for a cipher, if you allow many different ways to decode it is makes it easier to break.

I suspect that you mean:

"why it is important to have a key with a long lenght".

A long lenght key strenghtens the cipher against a brute force attack. Increasing the key lenght exponentially increases the number of combinations of which only one unlocks the code....

OR

"Why is it important for a "cryptographic system" to have a large number of potential keys.  

A large number of potential keys again makes a brute force attack diffficult as only one of many keys will work to decrypt the cipher into clear text.    AND a large number of potential keys will allow the cryptographic system to handle a large number of concurrent users to have their own dedicated keys. This prevents other users on the system from decrypting the cipher excluding all except the intended recipient from decoding the message.

Answer 2

what is a cipher

Answer 3

Your question have 2 outlets. It can be positive or negative. Discard anything that ends up to negative. Accept only those that ends up positive. You can understand what i mean if you know basic math. All i can say is that it can apply to anything.

Answer 4

Better...cypher than sorry?

Answer 5

Well with too few keys a cipher can be cracked by simply trying all the possibilities. With modern fast computers this can be done extremely rapidly so to get a cipher that can not be cracked one has to have huge numbers of possibilities. A 128 bit cipher has 3.40 E38 possibilities and that is getting to be not enough. As computer power increases more possibilities can be tried faster.