What I understood from CWSP book is ?Suppose I am using WEP key ID 3 at transmitter side for encryption then same key ID 3 must be used at receiver side for decryption??..correct me if I am wrong?. but suppose I am using key 3 with key= 693a7e9574 at transmitter and key 4 with same key 693a7e9574 at receiver side?..key 3 at receiver is having another key like 693a7e8888??do we decrypt the data at receiver side?how if answer is YES.
No. In this case, it would not properly decrypt the payload. When WEP encryption is used, the transmitter encrypts the payload using one of [up to] four possible keys. The transmitter also expands the frame body with encryption information, including a 4-octet IV field and a 4-octet ICV field. The IV field includes the initialization vector value as well as a 2-bit Key ID. The Key ID indicates the WEP key that was used to encrypt this payload. When the receiver processes this frame, it will use this Key ID field to select the appropriate key. If the configured keys do not match, the decryption will fail.