diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index 94ea88f..c809d9a 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -33,11 +33,32 @@
     TEST_ASSERT( mbedtls_cipher_info_from_string( info->name ) == info );
 
     key_bitlen = mbedtls_cipher_info_get_key_bitlen( info );
-    TEST_ASSERT( key_bitlen % 8 == 0 );
-    /* All current and plausible supported ciphers use a 64-bit, 128-bit
-     * or 256-bit key, except XTS which uses a double AES key. */
-    TEST_ASSERT( key_bitlen >= 64 );
-    TEST_ASSERT( key_bitlen <= 512 );
+    if( info->type == MBEDTLS_CIPHER_NULL )
+        TEST_ASSERT( key_bitlen == 0 );
+    else if( info->mode == MBEDTLS_MODE_XTS )
+    {
+        TEST_ASSERT( key_bitlen == 256 ||
+                     key_bitlen == 384 ||
+                     key_bitlen == 512 );
+    }
+    else if( ! strncmp( info->name, "DES-EDE3-", 9 ) )
+    {
+        TEST_ASSERT( key_bitlen == 192 );
+    }
+    else if( ! strncmp( info->name, "DES-EDE-", 8 ) )
+    {
+        TEST_ASSERT( key_bitlen == 128 );
+    }
+    else if( ! strncmp( info->name, "DES-", 4 ) )
+    {
+        TEST_ASSERT( key_bitlen == 64 );
+    }
+    else
+    {
+        TEST_ASSERT( key_bitlen == 128 ||
+                     key_bitlen == 192 ||
+                     key_bitlen == 256 );
+    }
 
     return( 1 );