WEP (Wired Equivalent Privacy) Wired Equivalent Privacy is a protocol to protect the security of wireless transmission. Originated in 1997, IEEE 802.11 was the first WiFi security standard.
WEP uses keys of 40 or 104 bits, and the keys do not change. Keys were initially limited to 40 bits because of U.S. government restrictions on encryption technology.
A 64-bit WEP is a 40-bit key plus a 24-bit initialization vector. 128-bit WEP uses a 104-bit key.
WEP uses the Rivest Cipher 4 stream cipher technique to ensure confidentiality, which was invented by Ron Rivest in 1987.
Due to the development of computing power, and its own shortcomings, WEP became easy to crack, and the WiFi Alliance retired it in 2004.