使用OpenSSL进行RSA非对称加密(C++版本)

Posted 2021-08-12 好儿郎-志在四方

使用OpenSSL进行RSA非对称加密（C++版本）

• • 运行环境
  • 环境准备
  • 源代码

运行环境

源代码运行环境，Widows 10，Qt Creator 5.14.1 MingW。

环境准备

关于OpenSSL，既可以下载源代码自己编译，也可以下载已经编译好的库，参见文章：https://blog.csdn.net/liang19890820/article/details/51658574

编译好之后，有如下目录结果：

需在 .pro工程文件中配置引用库和依赖路径：

INCLUDEPATH += $$PWD/openssl/include
DEPENDPATH += $$PWD/openssl/include

win32:CONFIG(release, debug|release): LIBS += -L$$PWD/openssl/lib/ -llibcrypto
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/openssl/lib/ -llibcrypto

源代码

#include "openssl/ssl.h"
#include "openssl/rsa.h"

#define BEGIN_RSA_PUBLIC_KEY    "BEGIN RSA PUBLIC KEY"
#define BEGIN_PUBLIC_KEY        "BEGIN PUBLIC KEY"

#define PUBLIC_KEY "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCYN5V1VTcOsHxBgccNPgujoNim5wpEaIy4q1zniuth23yKj+kiIJ47ltxBske7FfX4mTzxGKTfAXUacSWlXZ6oihd/wKjPvkjV4RyJjN9sejlofyaZDBXffWE8EL6UhBu3k9O+fPR/7USgqZ5JJE1QkeztigkR8d3Z5gmN7n8K3wIDAQAB"


QString rsa_pub_encrypt(const QString &cleardata)
{
    QString pubkey=PUBLIC_KEY;
    pubkey.insert(0, "-----BEGIN PUBLIC KEY-----\\n");
    pubkey.append("\\n-----END PUBLIC KEY-----\\n");

    QByteArray pubKeyArry = pubkey.toUtf8();
    uchar* pPubKey = (uchar*)pubKeyArry.data();
    BIO* pKeyBio = BIO_new_mem_buf(pPubKey, pubKeyArry.length());
    if (pKeyBio == NULL){
        return "";
    }

    RSA* pRsa = RSA_new();
    if ( pubkey.contains(BEGIN_RSA_PUBLIC_KEY) ){
        pRsa = PEM_read_bio_RSAPublicKey(pKeyBio, &pRsa, NULL, NULL);
    }else{
        pRsa = PEM_read_bio_RSA_PUBKEY(pKeyBio, &pRsa, NULL, NULL);
    }
    if ( pRsa == NULL ){
        BIO_free_all(pKeyBio);
        return "";
    }

    int nLen = RSA_size(pRsa);
    char* pEncryptBuf = new char[nLen];
    memset(pEncryptBuf, 0, nLen);

    QByteArray clearDataArry = cleardata.toUtf8();
    int nClearDataLen = clearDataArry.length();
    uchar* pClearData = (uchar*)clearDataArry.data();
    int nSize = RSA_public_encrypt(nClearDataLen,
                                   pClearData,
                                   (uchar*)pEncryptBuf,
                                   pRsa,
                                   RSA_PKCS1_PADDING);
    QString strEncryptData = "";
    if ( nSize >= 0 ){
        QByteArray arry(pEncryptBuf, nSize);
        strEncryptData = arry.toBase64();
    }

    // 释放内存
    delete[] pEncryptBuf;
    BIO_free_all(pKeyBio);
    RSA_free(pRsa);
    return strEncryptData;
}