Add HMAC-SHA256 support.
Change-Id: I64c7bdf77388e3cb491b702c52c6746d32f317b0
diff --git a/hmac_key.cpp b/hmac_key.cpp
new file mode 100644
index 0000000..40ecfe6
--- /dev/null
+++ b/hmac_key.cpp
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include "hmac_key.h"
+
+#include <openssl/err.h>
+#include <openssl/rand.h>
+
+#include "hmac_operation.h"
+
+namespace keymaster {
+
+Operation* HmacKey::CreateOperation(keymaster_purpose_t purpose, keymaster_error_t* error) {
+ *error = KM_ERROR_OK;
+
+ uint32_t tag_length;
+ if (!authorizations().GetTagValue(TAG_MAC_LENGTH, &tag_length))
+ *error = KM_ERROR_UNSUPPORTED_MAC_LENGTH;
+
+ keymaster_digest_t digest;
+ if (!authorizations().GetTagValue(TAG_DIGEST, &digest) || digest != KM_DIGEST_SHA_2_256)
+ *error = KM_ERROR_UNSUPPORTED_DIGEST;
+
+ if (*error != KM_ERROR_OK)
+ return NULL;
+
+ UniquePtr<Operation> op;
+ switch (purpose) {
+ case KM_PURPOSE_SIGN:
+ case KM_PURPOSE_VERIFY:
+ op.reset(
+ new HmacOperation(purpose, logger_, key_data(), key_data_size(), digest, tag_length));
+ break;
+ default:
+ *error = KM_ERROR_UNSUPPORTED_PURPOSE;
+ return NULL;
+ }
+
+ if (!op.get())
+ *error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
+
+ return op.release();
+}
+
+} // namespace keymaster