Original: Steve Miller and Clifford Neuman, the primary designers of Kerberos version 4, published that version in the late 1980s, although they had targeted it primarily for Project Athena.
Simplified: Steve Miller and Clifford Neuman, the primary designers of Kerberos version 4 (which used the DES encryption algorithm with 56-bit keys), published that version in 1989, although they had targeted it primarily for Project Athena.