Schneier made Blowfish as a general-purpose algorithm, to be used as a replacement for the old DES algorithm and to remove the problems and difficulties of other encryption algorithms. At the time Blowfish was released, many other algorithms were proprietary, or were secrets. Schneier has said that, "Blowfish is unpatented, and will remain so in all countries. The algorithm is hereby placed in the public domain, and can be freely used by anyone."