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openssl3.2 - 官方demo学习 - encrypt - rsa_encrypt.c

概述

从内存中的DER共钥数据构造pub_key, 用公钥加密明文, 输出密文. 非对称加密
从内存中的DER私钥数据构造priv_key, 用私钥解密密文, 输出明文, 非对称解密
使用的哪种非堆成加解密算法是生成证书中指定的.
在从DER证书中构造key时, 也要指定RSA参数.
在加解密初始化, 要设置RSA相关参数
加解密之前, 都有API可以从要操作的数据长度估算出操作后的数据长度
这个例子演示了从内存中拿数据来进行非对称加解密, 避免了公钥/私钥数据落地

笔记

/*!
\file rsa_encrypt.c
\note openssl3.2 - 官方demo学习 - encrypt - rsa_encrypt.c
从内存中的DER共钥数据构造pub_key, 用公钥加密明文, 输出密文. 非对称加密
从内存中的DER私钥数据构造priv_key, 用私钥解密密文, 输出铭文, 非对称解密
使用的哪种非堆成加解密算法是生成证书中指定的.
在从DER证书中构造key时, 也要指定RSA参数.
在加解密初始化, 要设置RSA相关参数
加解密之前, 都有API可以从要操作的数据长度估算出操作后的数据长度
这个例子演示了从内存中拿数据来进行非对称加解密, 避免了公钥/私钥数据落地
*//*-* Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.** Licensed under the Apache License 2.0 (the "License").  You may not use* this file except in compliance with the License.  You can obtain a copy* in the file LICENSE in the source distribution or at* https://www.openssl.org/source/license.html*//** An example that uses EVP_PKEY_encrypt and EVP_PKEY_decrypt methods* to encrypt and decrypt data using an RSA keypair.* RSA encryption produces different encrypted output each time it is run,* hence this is not a known answer test.*/#include <stdio.h>
#include <stdlib.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/decoder.h>
#include <openssl/core_names.h>
#include "rsa_encrypt.h"#include "my_openSSL_lib.h"/* Input data to encrypt */
static const unsigned char msg[] =
"To be, or not to be, that is the question,\n"
"Whether tis nobler in the minde to suffer\n"
"The slings and arrowes of outragious fortune,\n"
"Or to take Armes again in a sea of troubles";/** For do_encrypt(), load an RSA public key from pub_key_der[].* For do_decrypt(), load an RSA private key from priv_key_der[].*/
static EVP_PKEY* get_key(OSSL_LIB_CTX* libctx, const char* propq, int public)
{OSSL_DECODER_CTX* dctx = NULL;EVP_PKEY* pkey = NULL;int selection;const unsigned char* data;size_t data_len;if (public) {selection = EVP_PKEY_PUBLIC_KEY;data = g_pub_key_der;data_len = sizeof(g_pub_key_der);}else {selection = EVP_PKEY_KEYPAIR;data = g_priv_key_der;data_len = sizeof(g_priv_key_der);}dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, "DER", NULL, "RSA",selection, libctx, propq);(void)OSSL_DECODER_from_data(dctx, &data, &data_len);OSSL_DECODER_CTX_free(dctx);return pkey;
}/* Set optional parameters for RSA OAEP Padding */
static void set_optional_params(OSSL_PARAM* p, const char* propq)
{static unsigned char label[] = "label";/* "pkcs1" is used by default if the padding mode is not set */*p++ = OSSL_PARAM_construct_utf8_string(OSSL_ASYM_CIPHER_PARAM_PAD_MODE,OSSL_PKEY_RSA_PAD_MODE_OAEP, 0);/* No oaep_label is used if this is not set */*p++ = OSSL_PARAM_construct_octet_string(OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL,label, sizeof(label));/* "SHA1" is used if this is not set */*p++ = OSSL_PARAM_construct_utf8_string(OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST,"SHA256", 0);/** If a non default property query needs to be specified when fetching the* OAEP digest then it needs to be specified here.*/if (propq != NULL)*p++ = OSSL_PARAM_construct_utf8_string(OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS,(char*)propq, 0);/** OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST and* OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS can also be optionally added* here if the MGF1 digest differs from the OAEP digest.*/*p = OSSL_PARAM_construct_end();
}/** The length of the input data that can be encrypted is limited by the* RSA key length minus some additional bytes that depends on the padding mode.**/
static int do_encrypt(OSSL_LIB_CTX* libctx,const unsigned char* in, size_t in_len,unsigned char** out, size_t* out_len)
{int ret = 0, public = 1;size_t buf_len = 0;unsigned char* buf = NULL;const char* propq = NULL;EVP_PKEY_CTX* ctx = NULL;EVP_PKEY* pub_key = NULL;OSSL_PARAM params[5];/* Get public key */pub_key = get_key(libctx, propq, public);if (pub_key == NULL) {fprintf(stderr, "Get public key failed.\n");goto cleanup;}ctx = EVP_PKEY_CTX_new_from_pkey(libctx, pub_key, propq);if (ctx == NULL) {fprintf(stderr, "EVP_PKEY_CTX_new_from_pkey() failed.\n");goto cleanup;}set_optional_params(params, propq);/* If no optional parameters are required then NULL can be passed */if (EVP_PKEY_encrypt_init_ex(ctx, params) <= 0) {fprintf(stderr, "EVP_PKEY_encrypt_init_ex() failed.\n");goto cleanup;}/* Calculate the size required to hold the encrypted data */if (EVP_PKEY_encrypt(ctx, NULL, &buf_len, in, in_len) <= 0) {fprintf(stderr, "EVP_PKEY_encrypt() failed.\n");goto cleanup;}buf = OPENSSL_zalloc(buf_len);if (buf == NULL) {fprintf(stderr, "Malloc failed.\n");goto cleanup;}if (EVP_PKEY_encrypt(ctx, buf, &buf_len, in, in_len) <= 0) {fprintf(stderr, "EVP_PKEY_encrypt() failed.\n");goto cleanup;}*out_len = buf_len;*out = buf;fprintf(stdout, "Encrypted:\n");BIO_dump_indent_fp(stdout, buf, (int)buf_len, 2);fprintf(stdout, "\n");ret = 1;cleanup:if (!ret)OPENSSL_free(buf);EVP_PKEY_free(pub_key);EVP_PKEY_CTX_free(ctx);return ret;
}static int do_decrypt(OSSL_LIB_CTX* libctx, const char* in, size_t in_len,unsigned char** out, size_t* out_len)
{int ret = 0, public = 0;size_t buf_len = 0;unsigned char* buf = NULL;const char* propq = NULL;EVP_PKEY_CTX* ctx = NULL;EVP_PKEY* priv_key = NULL;OSSL_PARAM params[5];/* Get private key */priv_key = get_key(libctx, propq, public);if (priv_key == NULL) {fprintf(stderr, "Get private key failed.\n");goto cleanup;}ctx = EVP_PKEY_CTX_new_from_pkey(libctx, priv_key, propq);if (ctx == NULL) {fprintf(stderr, "EVP_PKEY_CTX_new_from_pkey() failed.\n");goto cleanup;}/* The parameters used for encryption must also be used for decryption */set_optional_params(params, propq);/* If no optional parameters are required then NULL can be passed */if (EVP_PKEY_decrypt_init_ex(ctx, params) <= 0) {fprintf(stderr, "EVP_PKEY_decrypt_init_ex() failed.\n");goto cleanup;}/* Calculate the size required to hold the decrypted data */if (EVP_PKEY_decrypt(ctx, NULL, &buf_len, in, in_len) <= 0) {fprintf(stderr, "EVP_PKEY_decrypt() failed.\n");goto cleanup;}buf = OPENSSL_zalloc(buf_len);if (buf == NULL) {fprintf(stderr, "Malloc failed.\n");goto cleanup;}if (EVP_PKEY_decrypt(ctx, buf, &buf_len, in, in_len) <= 0) {fprintf(stderr, "EVP_PKEY_decrypt() failed.\n");goto cleanup;}*out_len = buf_len;*out = buf;fprintf(stdout, "Decrypted:\n");BIO_dump_indent_fp(stdout, buf, (int)buf_len, 2);fprintf(stdout, "\n");ret = 1;cleanup:if (!ret)OPENSSL_free(buf);EVP_PKEY_free(priv_key);EVP_PKEY_CTX_free(ctx);return ret;
}int main(void)
{int ret = EXIT_FAILURE;size_t msg_len = sizeof(msg) - 1;size_t encrypted_len = 0, decrypted_len = 0;unsigned char* encrypted = NULL, * decrypted = NULL;OSSL_LIB_CTX* libctx = NULL;if (!do_encrypt(libctx, msg, msg_len, &encrypted, &encrypted_len)) {fprintf(stderr, "encryption failed.\n");goto cleanup;}if (!do_decrypt(libctx, encrypted, encrypted_len,&decrypted, &decrypted_len)) {fprintf(stderr, "decryption failed.\n");goto cleanup;}if (CRYPTO_memcmp(msg, decrypted, decrypted_len) != 0) {fprintf(stderr, "Decrypted data does not match expected value\n");goto cleanup;}ret = EXIT_SUCCESS;cleanup:OPENSSL_free(decrypted);OPENSSL_free(encrypted);OSSL_LIB_CTX_free(libctx);if (ret != EXIT_SUCCESS)ERR_print_errors_fp(stderr);return ret;
}

END