diff --git a/scripts/mbedtls_dev/crypto_knowledge.py b/scripts/mbedtls_dev/crypto_knowledge.py
index a1f426b..b8ca621 100644
--- a/scripts/mbedtls_dev/crypto_knowledge.py
+++ b/scripts/mbedtls_dev/crypto_knowledge.py
@@ -228,6 +228,9 @@
            alg.head in frozenset.union(BLOCK_MAC_MODES,
                                        BLOCK_CIPHER_MODES,
                                        BLOCK_AEAD_MODES):
+            if alg.head in ['CMAC', 'OFB'] and \
+               self.head in ['ARIA', 'CAMELLIA']:
+                return False # not implemented in Mbed TLS
             return True
         if self.head == 'CHACHA20' and alg.head == 'CHACHA20_POLY1305':
             return True