Use sodium function to generate curve25519 keypair

sbotc.c

@@ -100,14 +100,6 @@ static void usage() {
 	exit(EXIT_FAILURE);
 }
 
-static int auth_keypair(unsigned char *pk, unsigned char *sk, unsigned char *seed) {
-	unsigned char pk_ed[32], sk_ed[64];
-	int rc = crypto_sign_seed_keypair(pk_ed, sk_ed, seed);
-	rc |= crypto_sign_ed25519_pk_to_curve25519(pk, pk_ed);
-	rc |= crypto_sign_ed25519_sk_to_curve25519(sk, sk_ed);
-	return rc;
-}
-
 static int tcp_connect(const char *host, const char *port) {
 	struct addrinfo hints;
 	struct addrinfo *result, *rp;
@@ -166,9 +158,7 @@ static void shs_connect(int s, const unsigned char pubkey[32], const unsigned ch
 	unsigned char local_app_mac[32], remote_app_mac[32];
 
 	unsigned char kx_pk[32], kx_sk[32];
-	unsigned char seed[32];
-	randombytes_buf(seed, sizeof(seed));
-	rc = auth_keypair(kx_pk, kx_sk, seed);
+	rc = crypto_box_keypair(kx_pk, kx_sk);
 	if (rc < 0) errx(1, "failed to generate auth keypair");
 
 	rc = crypto_auth(local_app_mac, kx_pk, 32, appkey);