size_t modsize,
                      const void *context);
int ed25519_clone(Point **P, const Point *Q);
void ed25519_free_point(Point *p);
int ed25519_cmp(const Point *p1, const Point *p2);
int ed25519_neg(Point *p);
int ed25519_get_xy(uint8_t *xb, uint8_t *yb, size_t modsize, Point *p);
int ed25519_double(Point *p);
int ed25519_add(Point *P1, const Point *P2);
int ed25519_scalar(Point *P, const uint8_t *scalar, size_t scalar_len, uint64_t seed);
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