Public domain

C# port + code by Christian Winnerlein (CodesInChaos)

Poly1305 in c
        written by Andrew M. (floodyberry)
        original license: MIT or PUBLIC DOMAIN
        https://github.com/floodyberry/poly1305-donna/blob/master/poly1305-donna-unrolled.c

Curve25519 and Ed25519 in c
        written by Dan Bernstein (djb)
        public domain
        from Ref10 in SUPERCOP http://bench.cr.yp.to/supercop.html

(H)Salsa20 in c
        written by Dan Bernstein (djb)
        public domain
        from SUPERCOP http://bench.cr.yp.to/supercop.html

SHA512
        written by Christian Winnerlein (CodesInChaos)
        public domain
        directly from the specification