diff --git a/src/asn1.c b/src/asn1.c
index be9370f4..5e5b2628 100644
--- a/src/asn1.c
+++ b/src/asn1.c
@@ -38,7 +38,7 @@ const char *asn1_tag_name(int tag)
 	}
 
 	switch (tag & 0xc0) {
-	case ASN1_TAG_CONTENT_SPECIFIC: return asn1_tag_index[tag & 0xe0];
+	case ASN1_TAG_CONTENT_SPECIFIC: return asn1_tag_index[tag & 0x1f];
 	case ASN1_TAG_APPLICATION: return "Application";
 	case ASN1_TAG_PRIVATE: return "Private";
 	}
diff --git a/tests/asn1test.c b/tests/asn1test.c
index f1265e8e..47da8631 100644
--- a/tests/asn1test.c
+++ b/tests/asn1test.c
@@ -59,16 +59,18 @@ static void print_octets(const uint8_t *o, size_t olen)
 
 static int test_asn1_tag(void)
 {
-	int i;
-	format_print(stderr, 0, 0, "Tags:\n");
-	for (i = 1; i <= 13; i++) {
-		format_print(stderr, 0, 4, "%s (0x%02x)\n", asn1_tag_name(i), i);
-	}
-	for (i = 18; i <= 30; i++) {
-		format_print(stderr, 0, 4, "%s (0x%02x)\n", asn1_tag_name(i), i);
-	}
-	printf("%s() ok\n", __FUNCTION__);
-	return 1;
+    int tag;
+    format_print(stderr, 0, 0, "Testing all tag values from 0 to 255:\n");
+    for (tag = 0; tag <= 255; tag++) {
+        const char *name = asn1_tag_name(tag);
+        if (name) {
+            format_print(stderr, 0, 4, "%s (0x%02x)\n", name, tag);
+        } else {
+            format_print(stderr, 0, 4, "Unknown Tag (0x%02x)\n", tag);
+        }
+    }
+    printf("%s() ok\n", __FUNCTION__);
+    return 1;
 }
 
 static int test_asn1_length(void)