Framework for knowledge about key types

New Python module intended to gather knowledge about key types and
cryptographic mechanisms, such as the ability to create test data for
a given key type and the determination of whether an algorithm is
compatible with a key type.

This commit just creates a class for knowledge about key types.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

scripts/mbedtls_dev/crypto_knowledge.py

@@ -0,0 +1,51 @@
+"""Knowledge about cryptographic mechanisms implemented in Mbed TLS.
+
+This module is entirely based on the PSA API.
+"""
+
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import re
+from typing import List, Optional
+
+class KeyType:
+    """Knowledge about a PSA key type."""
+
+    def __init__(self, name: str, params: Optional[List[str]] = None):
+        """Analyze a key type.
+
+        The key type must be specified in PSA syntax. In its simplest form,
+        this is a string 'PSA_KEY_TYPE_xxx' which is the name of a PSA key
+        type macro. For key types that take arguments, the arguments can
+        be passed either through the optional argument `params` or by
+        passing an expression of the form 'PSA_KEY_TYPE_xxx(param1, param2)'
+        as the a string.
+        """
+        self.name = name.strip()
+        if params is None:
+            if '(' in self.name:
+                m = re.match(r'(\w+)\s*\((.*)\)\Z', self.name)
+                assert m is not None
+                self.name = m.group(1)
+                params = ','.split(m.group(2))
+        if params is None:
+            self.params = params
+        else:
+            self.params = [param.strip() for param in params]
+        self.expression = self.name
+        if self.params is not None:
+            self.expression += '(' + ', '.join(self.params) + ')'
+        self.private_type = re.sub(r'_PUBLIC_KEY\Z', r'_KEY_PAIR', self.name)