int secp256k1_borromean_sign(const secp256k1_ecmult_context *ecmult_ctx, const secp256k1_ecmult_gen_context *ecmult_gen_ctx, unsigned char *e0, secp256k1_scalar *s, const secp256k1_gej *pubs, const secp256k1_scalar *k, const secp256k1_scalar *sec, const size_t *rsizes, const size_t *secidx, size_t nrings, const unsigned char *m, size_t mlen)
int secp256k1_borromean_verify(const secp256k1_ecmult_context *ecmult_ctx, secp256k1_scalar *evalues, const unsigned char *e0, const secp256k1_scalar *s, const secp256k1_gej *pubs, const size_t *rsizes, size_t nrings, const unsigned char *m, size_t mlen)
"Borromean" ring signature.