文章目录
- openssl3.2 - 官方demo学习 - encode - ec_encode.c
- 概述
- 笔记
- 产生ecc私钥
- 产生ecc公钥
- 测试工程
- 备注
- 备注
- END
openssl3.2 - 官方demo学习 - encode - ec_encode.c
概述
官方demos/encode 目录中给了2个例子工程
功能是载入(RSA/ECC)公钥, 然后自己就可以拿内存中的公钥对象干活了.
刚开始过官方demo时, 没明白.
现在回头看, 挺简单的.
昨天已经将rsa_encode.c搞定了.
现在准备做ec_encode.c的实验.
肉眼分辨这2个.c, 区别很小. 用BC4看了一下区别, 主要是算法不同.
openssl的高级接口封装的真好, 类似的算法使用, 唯一的区别是算法名称不同.
笔记
产生ecc私钥
根据前面的实现(openssl3.2 - exp - 选择最好的内建椭圆曲线), 强度最好的内建椭圆曲线名称为 sect571k1/sect571r1, 2选1都行, 那我选择sect571r1
查看openssl帮助, 可知 openssl ecparam -genkey 可以产生ecc私钥.
查找ecparam -genkey, 在openssl源码中看到了产生ecc私钥的例子.
下面2种命令都行, 区别在将输出是否加密
输出分2段, 前面是EC参数, 后面是私钥
openssl ecparam -genkey -name sect571r1 -out ec_privkey_sect571r1_001.key输出只有一段, 内容被加密
openssl ecparam -genkey -name sect571r1 -param_enc explicit -out ec_privkey_sect571r1_001.key
对于ECC, 私钥产生和公钥产生是分开的, 并不像RSA那样(私钥里面包含公钥), 对于使用是这样. 私钥只能当私钥用, 公钥只能当公钥用.
但是用openssl命令是可以从同一个ECC私钥中, 导出相同的ECC公钥, 说明ECC公钥就在ECC私钥里面, ECC私钥是一个KeyPair.
产生ecc公钥
openssl ec -in ec_privkey_sect571r1_001.key -pubout -out ec_pubkey_sect571r1_001.key
openssl ec -in ec_privkey_sect571r1_001.key -pubout
执行多次, 看到的公钥都是一样的, 说明ecc公钥包含在ecc私钥里面
跟一下, 看看怎么从ecc私钥中取ecc公钥.
将ec_privkey_sect571r1_001.key转成C数组, 就可以在工程中, 通过buffer来载入公钥了.
既然载入不同类型(RSA/ECC)公钥, 只有算法名称不同. 将测试程序改了一下, 载入私钥时, 参数为密钥文件类型 + buffer + buffer_lenn
测试工程
/*!
* \file main.cpp
* \note openssl3.2 - 官方demo学习 - encode - ec_encode.c
* 对于ecc的pem数据, 只能载入ecc公钥到 EVP_PKEY
* 如果给的是ecc私钥, 无法从私钥中载入公钥 到 EVP_PKEY
* 如果想从ecc私钥中载入公钥, 可以参照 openssl ec -in ec_privkey_sect571r1_001.key -pubout
*/
#include "my_openSSL_lib.h"
#include <openssl/crypto.h>
#include <openssl/bio.h>
#include <openssl/decoder.h>
#include <openssl/encoder.h>
#include <openssl/evp.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include "CMemHookRec.h"
// 为了内存操作, 已经将私钥数据文件转成了数组, 嵌入到工程中
//! \ref https://lostspeed.blog.csdn.net/article/details/136486115
//! 数组为 const char ucAry_ecc_priv_key_for_test[472];
#include "ecc_priv_key_for_test.h"
#include "ecc_pub_key_for_test.h" // ucAry_ecc_pub_key_for_test
#include "ec_privkey_sect571r1_pub_priv.h" // ucAry_ec_privkey_sect571r1_pub_priv
#include <cassert>
#define PWD_PRIV_KEY NULL
void my_openssl_app();
// 都是在操作内存, 从内存中的私钥数据, 转出到内存中的公钥数据
bool exportRsaPrivKeyToRsaPubKey(bool isPrivkeyBuffer, const char* key_type, const char* pBufPrivKey, int lenPrivKey, const char* pBufPrivKeyPwd, char*& pBufPubKey, int& lenPubKey);
// 载入buffer到 EVP_PKEY时, 不区分是公钥还是私钥, 只要是有效的key数据, 都能正常载入
EVP_PKEY* load_key(bool isPrivkeyBuffer, const char* key_type, OSSL_LIB_CTX* libctx, const char* pBufPrivKey, int lenPrivKey, const char* passphrase);
bool export_Key(bool isPrivkeyBuffer, EVP_PKEY* pkey, const char* passphrase, char*& pBufPubKey, int& lenPubKey);
int main(int argc, char** argv)
{
setvbuf(stdout, NULL, _IONBF, 0); // 清掉stdout缓存, 防止调用printf时阻塞
mem_hook();
my_openssl_app();
mem_unhook();
/*! run result
*/
return 0;
}
void my_openssl_app()
{
bool b_rc = false;
char* pszPubKey = NULL;
int lenPubKey = 0;
BIO* bio_out = BIO_new_fp(stdout, 0);
assert(NULL != bio_out);
do {
// 载入公钥
// 这个函数只能载入公钥, 如果像ecc私钥, 是无法载入公钥的
// 但是 openssl ec -in ec_privkey_sect571r1_001.key -pubout -out ec_pubkey_sect571r1_001.key 可以, 一会跟一下
// 执行上面这个命令多次, 看到的公钥都是一样的, 说明 ecc私钥中包含ecc公钥数据
// 载入公钥数组(单独的ecc公钥文件转换来的) ok
// b_rc = exportRsaPrivKeyToRsaPubKey(false, "EC", ucAry_ecc_pub_key_for_test, sizeof(ucAry_ecc_pub_key_for_test), PWD_PRIV_KEY, pszPubKey, lenPubKey); // ok
// 载入私钥数组(单独的ecc私钥文件转换来的) err
b_rc = exportRsaPrivKeyToRsaPubKey(true, "EC", ucAry_ecc_priv_key_for_test, sizeof(ucAry_ecc_priv_key_for_test), PWD_PRIV_KEY, pszPubKey, lenPubKey); // err
// 载入公钥和私钥数组(自己手工拼的, 前面是ecc私钥文件, 后面呢是ecc公钥文件), err
// b_rc = exportRsaPrivKeyToRsaPubKey(false, "EC", ucAry_ec_privkey_sect571r1_pub_priv, sizeof(ucAry_ec_privkey_sect571r1_pub_priv), PWD_PRIV_KEY, pszPubKey, lenPubKey); // err
// 结论 - 这个官方例子, 只能单独载入ecc公钥文件, 得到公钥数据
// 对于rsa这种(私钥中包含公钥), 可以直接从私钥中得到公钥
// 对于ecc这样(私钥中也包含公钥), 却不可以直接从私钥中得到公钥, 一会看看 openssl ec -in ec_privkey_sect571r1_001.key -pubout 咋实现的
BIO_printf(bio_out, "b_rc = %s\n", (b_rc ? "true" : "false"));
if (!b_rc)
{
assert(false);
break;
}
// now can use pszPubKey
BIO_printf(bio_out, "the EC public key is below:\n");
BIO_dump_fp(stdout, pszPubKey, lenPubKey);
} while (false);
if (NULL != pszPubKey)
{
OPENSSL_free(pszPubKey);
pszPubKey = NULL;
}
if (NULL != bio_out)
{
BIO_free(bio_out);
bio_out = NULL;
}
}
bool exportRsaPrivKeyToRsaPubKey(bool isPrivkeyBuffer, const char* key_type, const char* pBufPrivKey, int lenPrivKey, const char* pBufPrivKeyPwd, char*& pBufPubKey, int& lenPubKey)
{
bool b_rc = false;
EVP_PKEY* pubKey = NULL;
do {
// 如果ras私钥是没有口令保护的, 可以不给口令
if ((NULL == pBufPrivKey) || (lenPrivKey <= 0))
{
break;
}
pubKey = load_key(isPrivkeyBuffer, "EC", NULL, pBufPrivKey, lenPrivKey, pBufPrivKeyPwd);
if (NULL == pubKey)
{
break;
}
if (!export_Key(isPrivkeyBuffer, pubKey, NULL, pBufPubKey, lenPubKey))
{
break;
}
b_rc = true;
} while (false);
if (NULL != pubKey)
{
EVP_PKEY_free(pubKey);
pubKey = NULL;
}
return b_rc;
}
EVP_PKEY* load_key(bool isPrivkeyBuffer, const char* key_type, OSSL_LIB_CTX* libctx, const char* pBufPrivKey, int lenPrivKey, const char* passphrase)
{
int ret = 0;
EVP_PKEY* pkey = NULL;
OSSL_DECODER_CTX* dctx = NULL;
int selection = 0;
int i_tmp = 0;
BIO* bio_privKey = NULL;
if (NULL == key_type)
{
goto cleanup;
}
bio_privKey = BIO_new(BIO_s_mem());
if (NULL == bio_privKey)
{
goto cleanup;
}
i_tmp = BIO_write(bio_privKey, pBufPrivKey, lenPrivKey);
if (i_tmp != lenPrivKey)
{
goto cleanup;
}
/*
* Create PEM decoder context expecting an RSA key.
*
* For raw (non-PEM-encoded) keys, change "PEM" to "DER".
*
* The selection argument here specifies whether we are willing to accept a
* public key, private key, or either. If it is set to zero, either will be
* accepted. If set to EVP_PKEY_KEYPAIR, a private key will be required, and
* if set to EVP_PKEY_PUBLIC_KEY, a public key will be required.
*/
dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, "PEM", NULL, key_type,
selection,
libctx, NULL);
if (dctx == NULL) {
// fprintf(stderr, "OSSL_DECODER_CTX_new_for_pkey() failed\n");
goto cleanup;
}
/*
* Set passphrase if provided; needed to decrypt encrypted PEM files.
* If the input is not encrypted, any passphrase provided is ignored.
*
* Alternative methods for specifying passphrases exist, such as a callback
* (see OSSL_DECODER_CTX_set_passphrase_cb(3)), which may be more useful for
* interactive applications which do not know if a passphrase should be
* prompted for in advance, or for GUI applications.
*/
if (passphrase != NULL) {
if (OSSL_DECODER_CTX_set_passphrase(dctx,
(const unsigned char*)passphrase,
strlen(passphrase)) == 0) {
// fprintf(stderr, "OSSL_DECODER_CTX_set_passphrase() failed\n");
goto cleanup;
}
}
/* Do the decode, reading from file. */
if (OSSL_DECODER_from_bio(dctx, bio_privKey) == 0) { // 如果f是stdin, 就需要自己输入私钥内容, 所以函数入参的f必须是一个实际文件的FILE*
// fprintf(stderr, "OSSL_DECODER_from_fp() failed\n");
goto cleanup;
}
ret = 1;
cleanup:
OSSL_DECODER_CTX_free(dctx);
/*
* pkey is created by OSSL_DECODER_CTX_new_for_pkey, but we
* might fail subsequently, so ensure it's properly freed
* in this case.
*/
if (ret == 0) {
EVP_PKEY_free(pkey);
pkey = NULL;
}
if (NULL != bio_privKey)
{
BIO_free(bio_privKey);
bio_privKey = NULL;
}
return pkey;
}
bool export_Key(bool isPrivkeyBuffer, EVP_PKEY* pkey, const char* passphrase, char*& pBufPubKey, int& lenPubKey)
{
int ret = 0;
int selection;
OSSL_ENCODER_CTX* ectx = NULL;
unsigned char* pdata = NULL;
size_t sz_len_data = 0;
/*
* Create a PEM encoder context.
*
* For raw (non-PEM-encoded) output, change "PEM" to "DER".
*
* The selection argument controls whether the private key is exported
* (EVP_PKEY_KEYPAIR), or only the public key (EVP_PKEY_PUBLIC_KEY). The
* former will fail if we only have a public key.
*
* Note that unlike the decode API, you cannot specify zero here.
*
* Purely for the sake of demonstration, here we choose to export the whole
* key if a passphrase is provided and the public key otherwise.
*/
// 如果给出口令, 就导出公私钥对;
// 如果不给口令, 就只导出公钥
// 实际应用中, 我们就只有导出公钥的需求
/*selection = (passphrase != NULL)
? EVP_PKEY_KEYPAIR
: EVP_PKEY_PUBLIC_KEY;*/
// 不根据口令来判断要从EVP_PKEY中选择啥数据
// 而是按照我们自己传的参数(如果load_key时的buffer是私钥数据, 就会传true; 如果载入的是公钥数据, 就会传false)
// 如果我们载入的是私钥数据(e.g. ECC私钥, 那么OSSL_ENCODER_CTX_new_for_pkey要选择公钥数据, 就会失败)
// ecc私钥中就有公钥数据, 但是OSSL_ENCODER_CTX_new_for_pkey载入的是啥, 要指定好
selection = (isPrivkeyBuffer ? EVP_PKEY_KEYPAIR : EVP_PKEY_PUBLIC_KEY);
// selection = EVP_PKEY_PUBLIC_KEY; // 就选择公钥呢? 也不行
// selection = EVP_PKEY_KEYPAIR; // 载入的是私钥数据, 导出私钥数据行么? 也不行
// 如果载入的是ECC私钥, 确要导出ECC公钥, OSSL_ENCODER_to_data()会失败
// 就只能载入ECC公钥, 导出ECC公钥数据才行. 关键是我就有要用的公钥/私钥数据, 为啥要导出, 不是很懂官方的意思.
ectx = OSSL_ENCODER_CTX_new_for_pkey(pkey, selection, "PEM", NULL, NULL);
if (ectx == NULL) {
// fprintf(stderr, "OSSL_ENCODER_CTX_new_for_pkey() failed\n");
goto cleanup;
}
/*
* Set passphrase if provided; the encoded output will then be encrypted
* using the passphrase.
*
* Alternative methods for specifying passphrases exist, such as a callback
* (see OSSL_ENCODER_CTX_set_passphrase_cb(3), just as for OSSL_DECODER_CTX;
* however you are less likely to need them as you presumably know whether
* encryption is desired in advance.
*
* Note that specifying a passphrase alone is not enough to cause the
* key to be encrypted. You must set both a cipher and a passphrase.
*/
if (passphrase != NULL) {
/* Set cipher. AES-128-CBC is a reasonable default. */
if (OSSL_ENCODER_CTX_set_cipher(ectx, "AES-128-CBC", NULL) == 0) {
// fprintf(stderr, "OSSL_ENCODER_CTX_set_cipher() failed\n");
goto cleanup;
}
/* Set passphrase. */
if (OSSL_ENCODER_CTX_set_passphrase(ectx,
(const unsigned char*)passphrase,
strlen(passphrase)) == 0) {
// fprintf(stderr, "OSSL_ENCODER_CTX_set_passphrase() failed\n");
goto cleanup;
}
}
/* Do the encode, writing to the given file. */
if (OSSL_ENCODER_to_data(ectx, &pdata, &sz_len_data) == 0) {
// fprintf(stderr, "OSSL_ENCODER_to_fp() failed\n");
goto cleanup;
}
pBufPubKey = (char*)pdata;
lenPubKey = (int)sz_len_data;
ret = 1;
cleanup:
OSSL_ENCODER_CTX_free(ectx);
return ret;
}
备注
跟了 openssl ec -in ec_privkey_sect571r1_001.key -pubout
大部分都是内部函数, 不好整理出来.
想了一下, 现在用官方demo, 主要是导出key出错.
但是载入私钥/公钥到EVP_PKEY, 都是成功的. 也就是说 load_key()一个有效的密钥/公钥buffer, 总可以得到一个有效的EVP_PKEY.
那就拿这个EVP_PKEY干活就完了, 也不导出什么公钥了.
需要私钥时, 就load_key()私钥buffer, 得到EVP_PKEY干活.
需要公钥时, 就load_key()公钥buffer, 得到EVP_PKEY干活.
官方demo实现中, 如果载入的buffer需要口令, 就当私钥来载入, 这个有点容易误判, 一会改一下. 从参数传入, 这个buffer是公钥还是私钥.
代码已经更新了, 不好使.
载入ECC私钥, 但是要导出ECC公钥数据时失败.
那么就拿官方这个demo当作load_key()用好了, 我们载入一个buffer(里面是有效的公钥文件/私钥文件转换来的数组), 得到一个EVP_PKEY干活. 先这样.
备注
从EVP_PKEY中拿到公钥/私钥, 官方另外一个工程中有演示, openssl3.2 - 官方demo学习 - pkey - EVP_PKEY_EC_keygen.c
那就可以在本工程中载入buffer之后, 得到key. 再从key中得到公钥和私钥的数据.
不行啊, 做了实验了.
int get_key_values(EVP_PKEY* pkey)
{
// 载入ECC私钥时, 用get_key_values()实现, 除了名字, 啥也得不到.
/*
Curve name: sect571r1
Failed to get public key
Failed to get private key
*/
// 载入手工拼装的合体文件(ECC私钥 + ECC公钥)buffer时, 用get_key_values()实现, 除了名字, 啥也得不到.
// 载入ECC公钥时, 用get_key_values()实现, 除了名字, 啥也得不到.
// 为啥呢? get_key_values()用程序来产生ECC密钥对那个工程(EVP_PKEY_EC_keygen.c)好使的
int ret = 0;
// 载入密钥对的buffer长度要给够
char out_curvename[0x100];
unsigned char out_pubkey[0x100];
unsigned char out_privkey[0x100];
BIGNUM* out_priv = NULL;
size_t out_pubkey_len, out_privkey_len = 0;
if (!EVP_PKEY_get_utf8_string_param(pkey, OSSL_PKEY_PARAM_GROUP_NAME,
out_curvename, sizeof(out_curvename),
NULL)) {
fprintf(stderr, "Failed to get curve name\n");
// goto cleanup;
}
else {
fprintf(stdout, "Curve name: %s\n", out_curvename);
}
if (!EVP_PKEY_get_octet_string_param(pkey, OSSL_PKEY_PARAM_PUB_KEY,
out_pubkey, sizeof(out_pubkey),
&out_pubkey_len)) {
fprintf(stderr, "Failed to get public key\n");
// goto cleanup;
}
else {
fprintf(stdout, "Public key:\n");
BIO_dump_indent_fp(stdout, out_pubkey, (int)out_pubkey_len, 2);
}
if (!EVP_PKEY_get_bn_param(pkey, OSSL_PKEY_PARAM_PRIV_KEY, &out_priv)) {
fprintf(stderr, "Failed to get private key\n");
// goto cleanup;
}
else {
out_privkey_len = BN_bn2bin(out_priv, out_privkey);
if (out_privkey_len <= 0 || out_privkey_len > sizeof(out_privkey)) {
fprintf(stderr, "BN_bn2bin failed\n");
// goto cleanup;
}
else {
fprintf(stdout, "Private Key:\n");
BIO_dump_indent_fp(stdout, out_privkey, (int)out_privkey_len, 2);
}
}
ret = 1;
// cleanup:
/* Zeroize the private key data when we free it */
if (NULL != out_priv)
{
BN_clear_free(out_priv);
}
return ret;
}
还是用EVP_PKEY_EC_keygen.c来产生ecc密钥对, 不用openssl自带的了. 跟了一下, 只能看出EVP_PKEY_EC_keygen.c调用的函数比较简洁.
