diff --git a/ctaocrypt/test/test.c b/ctaocrypt/test/test.c
index 8eac3de8d..88a3e475a 100644
--- a/ctaocrypt/test/test.c
+++ b/ctaocrypt/test/test.c
@@ -1941,40 +1941,88 @@ int gmac_test(void)
 {
     Gmac gmac;
 
-    const byte k[] =
+    const byte k1[] =
     {
         0x89, 0xc9, 0x49, 0xe9, 0xc8, 0x04, 0xaf, 0x01,
         0x4d, 0x56, 0x04, 0xb3, 0x94, 0x59, 0xf2, 0xc8
     };
-
-    const byte iv[] =
+    const byte iv1[] =
     {
         0xd1, 0xb1, 0x04, 0xc8, 0x15, 0xbf, 0x1e, 0x94,
         0xe2, 0x8c, 0x8f, 0x16
     };
-
-    const byte a[] =
+    const byte a1[] =
     {
        0x82, 0xad, 0xcd, 0x63, 0x8d, 0x3f, 0xa9, 0xd9,
        0xf3, 0xe8, 0x41, 0x00, 0xd6, 0x1e, 0x07, 0x77
     };
-
-    const byte t[] =
+    const byte t1[] =
     {
         0x88, 0xdb, 0x9d, 0x62, 0x17, 0x2e, 0xd0, 0x43,
         0xaa, 0x10, 0xf1, 0x6d, 0x22, 0x7d, 0xc4, 0x1b
     };
 
-    byte t2[sizeof(t)];
+    const byte k2[] =
+    {
+        0x40, 0xf7, 0xec, 0xb2, 0x52, 0x6d, 0xaa, 0xd4,
+        0x74, 0x25, 0x1d, 0xf4, 0x88, 0x9e, 0xf6, 0x5b
+    };
+    const byte iv2[] =
+    {
+        0xee, 0x9c, 0x6e, 0x06, 0x15, 0x45, 0x45, 0x03,
+        0x1a, 0x60, 0x24, 0xa7
+    };
+    const byte a2[] =
+    {
+        0x94, 0x81, 0x2c, 0x87, 0x07, 0x4e, 0x15, 0x18,
+        0x34, 0xb8, 0x35, 0xaf, 0x1c, 0xa5, 0x7e, 0x56
+    };
+    const byte t2[] =
+    {
+        0xc6, 0x81, 0x79, 0x8e, 0x3d, 0xda, 0xb0, 0x9f,
+        0x8d, 0x83, 0xb0, 0xbb, 0x14, 0xb6, 0x91
+    };
 
-    memset(t2, 0, sizeof(t2));
+    const byte k3[] =
+    {
+        0xb8, 0xe4, 0x9a, 0x5e, 0x37, 0xf9, 0x98, 0x2b,
+        0xb9, 0x6d, 0xd0, 0xc9, 0xb6, 0xab, 0x26, 0xac
+    };
+    const byte iv3[] =
+    {
+        0xe4, 0x4a, 0x42, 0x18, 0x8c, 0xae, 0x94, 0x92,
+        0x6a, 0x9c, 0x26, 0xb0
+    };
+    const byte a3[] =
+    {
+        0x9d, 0xb9, 0x61, 0x68, 0xa6, 0x76, 0x7a, 0x31,
+        0xf8, 0x29, 0xe4, 0x72, 0x61, 0x68, 0x3f, 0x8a
+    };
+    const byte t3[] =
+    {
+        0x23, 0xe2, 0x9f, 0x66, 0xe4, 0xc6, 0x52, 0x48
+    };
 
-    GmacSetKey(&gmac, k, sizeof(k));
-    GmacUpdate(&gmac, iv, sizeof(iv), a, sizeof(a), t2, sizeof(t2));
+    byte tag[16];
 
-    if (memcmp(t, t2, sizeof(t2)) != 0)
+    memset(tag, 0, sizeof(tag));
+    GmacSetKey(&gmac, k1, sizeof(k1));
+    GmacUpdate(&gmac, iv1, sizeof(iv1), a1, sizeof(a1), tag, sizeof(t1));
+    if (memcmp(t1, tag, sizeof(t1)) != 0)
         return -126;
 
+    memset(tag, 0, sizeof(tag));
+    GmacSetKey(&gmac, k2, sizeof(k2));
+    GmacUpdate(&gmac, iv2, sizeof(iv2), a2, sizeof(a2), tag, sizeof(t2));
+    if (memcmp(t2, tag, sizeof(t2)) != 0)
+        return -127;
+
+    memset(tag, 0, sizeof(tag));
+    GmacSetKey(&gmac, k3, sizeof(k3));
+    GmacUpdate(&gmac, iv3, sizeof(iv3), a3, sizeof(a3), tag, sizeof(t3));
+    if (memcmp(t3, tag, sizeof(t3)) != 0)
+        return -128;
+
     return 0;
 }
 #endif /* HAVE_AESGCM */