Cyber Security what is a onetime pad and what are its advant

 Cyber Security:  -what is a one-time pad  and what are its advantages and disadvantages? 

 -what is blockcipher and how many bits AES uses for its key and block size? 

Solution

1)

One-time pad

is a pad of keys for a cipher,where we destroy each page after a single use. so that each message is sent using a unique/seperate/different key

Advantages of one-time pad

1)It cannot be cracked easily

2)Information is kept fully secret

disadvantage of one-time pad

1)very long keys.Their size is almost same as message size

2)only one message can be encrypted securely or safely

2)block cipher is also called as stream cipher.It is the approach of encrypting plain text to obtain ciphertext in which a cryptographic key and algorithm are applied to a block of contigious data at once as a group rather than to single bit at a time.

block size of AES(Advanced encryption standard):128 bits

key size:

3 sizes: 128,192,256 bits