def decode
import bend-collections@1.0.0.0/src/crypto/ed25519/point.bend as Pointimport Base
import bend-collections@1.0.0.0/src/crypto/curve25519/field.bend as F
import bend-collections@1.0.0.0/src/crypto/curve25519/x25519.bend as X
170# RFC 8032 5.1.3 on 32 bytes below 256
171def decode(+c: Cs, +bs: List<&2, U32>) -> Maybe<&2, Pt>:
172 +y = F.of_bytes(bs)
173 dec_y(c, y, X.kbit(bs, 255n), ge_p(y))