feat: add gmssl headers

include/gmssl/sm2_key_share.h

@@ -0,0 +1,45 @@
+/*
+ *  Copyright 2014-2022 The GmSSL Project. All Rights Reserved.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the License); you may
+ *  not use this file except in compliance with the License.
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+// SM2 Key Shamir Secret Sharing
+
+
+#ifndef GMSSL_SM2_KEY_SHARE_H
+#define GMSSL_SM2_KEY_SHARE_H
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <gmssl/sm2.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+#define SM2_KEY_MAX_SHARES 12 // 12! = 479001600 < 2^31 = 2147483648
+
+
+typedef struct {
+	SM2_KEY key;
+	size_t index;
+	size_t total_cnt;
+} SM2_KEY_SHARE;
+
+int sm2_key_split(const SM2_KEY *key, size_t recover_cnt, size_t total_cnt, SM2_KEY_SHARE *shares);
+int sm2_key_recover(SM2_KEY *key, const SM2_KEY_SHARE *shares, size_t shares_cnt);
+int sm2_key_share_encrypt_to_file(const SM2_KEY_SHARE *share, const char *pass, const char *path_prefix);
+int sm2_key_share_decrypt_from_file(SM2_KEY_SHARE *share, const char *pass, const char *file);
+int sm2_key_share_print(FILE *fp, int fmt, int ind, const char *label, const SM2_KEY_SHARE *share);
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif