diff --git a/oqsprov/oqs_prov.h b/oqsprov/oqs_prov.h
index bb8ed1a9..33d74350 100644
--- a/oqsprov/oqs_prov.h
+++ b/oqsprov/oqs_prov.h
@@ -203,7 +203,7 @@ char *get_oqsname_fromtls(char *tlsname);
 char *get_oqsname(int nid);
 char *get_cmpname(int nid, int index);
 int get_oqsalg_idx(int nid);
-int get_composite_idx(int idx);
+int get_composite_idx(char *name);
 
 /* Workaround for not functioning EC PARAM initialization
  * TBD, check https://github.com/openssl/openssl/issues/16989
diff --git a/oqsprov/oqs_sig.c b/oqsprov/oqs_sig.c
index 83305bb2..91250642 100644
--- a/oqsprov/oqs_sig.c
+++ b/oqsprov/oqs_sig.c
@@ -447,7 +447,7 @@ static int oqs_sig_sign(void *vpoqs_sigctx, unsigned char *sig, size_t *siglen,
         unsigned char *buf;
         int i;
         int nid = OBJ_sn2nid(oqsxkey->tls_name);
-        int comp_idx = get_composite_idx(get_oqsalg_idx(nid));
+        int comp_idx = get_composite_idx(oqsxkey->tls_name);
         if (comp_idx == -1)
             goto endsign;
         const unsigned char *oid_prefix = composite_OID_prefix[comp_idx - 1];
@@ -799,7 +799,7 @@ static int oqs_sig_verify(void *vpoqs_sigctx, const unsigned char *sig,
         CompositeSignature *compsig;
         int i;
         int nid = OBJ_sn2nid(oqsxkey->tls_name);
-        int comp_idx = get_composite_idx(get_oqsalg_idx(nid));
+        int comp_idx = get_composite_idx(oqsxkey->tls_name);
         if (comp_idx == -1)
             goto endverify;
         unsigned char *buf;
diff --git a/oqsprov/oqsprov.c b/oqsprov/oqsprov.c
index 899032c3..559e9826 100644
--- a/oqsprov/oqsprov.c
+++ b/oqsprov/oqsprov.c
@@ -997,13 +997,20 @@ static const OSSL_ALGORITHM oqsprovider_decoder[] = {
 };
 
 // get the last number on the composite OID
-int get_composite_idx(int idx) {
-    char *s;
+int get_composite_idx(char *name) {
+    char *s = NULL;
     int i, len, ret = -1, count = 0;
 
-    if (2 * idx > OQS_OID_CNT)
-        return 0;
-    s = (char *)oqs_oid_alg_list[idx * 2];
+    for (i = 1; i <= OQS_OID_CNT; i += 2) {
+        if (!strcmp((char *)oqs_oid_alg_list[i], name)) {
+            s = (char *)oqs_oid_alg_list[i - 1];
+            break;
+        }
+    }
+    if (s == NULL) {
+        return ret;
+    }
+
     len = strlen(s);
 
     for (i = 0; i < len; i++) {