diff --git a/src/dpp-util.c b/src/dpp-util.c
index c805b14a..cfdedbdd 100644
--- a/src/dpp-util.c
+++ b/src/dpp-util.c
@@ -1376,8 +1376,9 @@ bool dpp_derive_z(const uint8_t *mac_i, const uint8_t *mac_r,
 	hkdf_extract(sha, NULL, 0, 1, prk, k_x, bytes);
 
 	/* HKDF-Extract (since it doesn't take non-string arguments)*/
-	prf_plus(sha, prk, bytes, z_out, bytes, 5, mac_i, 6, mac_r, 6, m_x,
-			bytes, n_x, bytes, key, strlen(key));
+	prf_plus(sha, prk, bytes, z_out, bytes, 5,
+		mac_i, (size_t) 6, mac_r, (size_t) 6, m_x, bytes,
+		n_x, bytes, key, strlen(key));
 
 	*z_len = bytes;
 
diff --git a/src/erp.c b/src/erp.c
index 85923346..05d1b3e2 100644
--- a/src/erp.c
+++ b/src/erp.c
@@ -325,7 +325,7 @@ static bool erp_derive_reauth_keys(const uint8_t *emsk, size_t emsk_len,
 	if (!prf_plus(L_CHECKSUM_SHA256, r_rk, emsk_len,
 				r_ik, emsk_len, 3, ERP_RIK_LABEL,
 				strlen(ERP_RIK_LABEL) + 1,
-				&cryptosuite, 1, &len, sizeof(len)))
+				&cryptosuite, (size_t) 1, &len, sizeof(len)))
 		return false;
 
 	return true;