Which of the following is not a proprietary encryption algorithm?
A.
RC2
B.
RC4
C.
Blowfish
D.
Skipjack
Explanation:
Blowfish is a symmetric block cipher with variable-length key (32 to
448 bits) designed in 1993 by Bruce Schneier as an unpatented, license-free,
royalty-free replacement for DES or IDEA.