Question

我尝试使用OpenSSL库在c ++中实现ssl握手（在上下文中，因为节点通过网关进行通信，所以我不能使用已经实现的ssl套接字）

让我们有发件人和收件人

发件人将证书发送给收件人
Receiver从发件人pub_key（包含在证书中）
Receiver使用发件人pub_key加密AES密钥，然后使用其私钥将其发送给发件人（连同其证书）
发件人使用接收者pub_key然后使用其私钥

使用RSA_PKCS1_PADDING进行公共加密使用RSA_NO_PADDING进行私有加密

现在，私人解密部分使用

error:0407106B:rsa routines:RSA_padding_check_PKCS1_type_2:block type is not 02

我不知道如何解决这个问题。

整个代码：

#include <iostream>
#include "openssl/bio.h"
#include "openssl/evp.h"
#include "openssl/aes.h"
#include "openssl/err.h"
#include <openssl/pem.h>
using namespace std;

int main(int argc, char *argv[]) {
  int ret = 0;

  ERR_load_crypto_strings();
  OpenSSL_add_all_algorithms();

  srand(time(NULL));

  X509 *sender_x, *receiver_x;
  RSA *sender_priv_key, *sender_pub_key, *receiver_priv_key, *receiver_pub_key;
  EVP_PKEY *sender_evp_key, *receiver_evp_key;

  string sender_ssl_cert = "unit_test/ini/00000000000Wcert.pem";
  string sender_ssl_key = "unit_test/ini/00000000000Wkey.pem";
  string receiver_ssl_cert = "unit_test/ini/00000000000Rcert.pem";
  string receiver_ssl_key = "unit_test/ini/00000000000Rkey.pem";
  string ssl_ca="unit_test/ini/sitsroot.pem";
  BIO *bio = BIO_new(BIO_s_mem());
    unsigned char tmp_buf[2000 + 1];

    unsigned char key[32], iv[32];

    /** **************************************************************** */
    /** ************************ READ FILES **************************** */
    FILE *f;
    if ((f = fopen(sender_ssl_cert.c_str(), "r")) == NULL) {
      cout << "failed to open file " << sender_ssl_cert << endl;
      return -1;
    }
    if ((sender_x = PEM_read_X509(f, NULL, NULL, NULL)) == NULL) {
      cout << "failed to read cert file " << sender_ssl_cert << endl;
      fclose(f);
      return -1;
    }
    fclose(f);

    if ((f = fopen(sender_ssl_key.c_str(), "r")) == NULL) {
      cout << "failed to open file " << sender_ssl_key << endl;
      return -1;
    }
    if ((sender_priv_key = PEM_read_RSAPrivateKey(f, NULL, NULL, NULL)) == NULL) {
      cout << "failed to read cert file " << sender_ssl_key << endl;
      fclose(f);
      return -1;
    }
    fclose(f);

    if ((f = fopen(receiver_ssl_cert.c_str(), "r")) == NULL) {
      cout << "failed to open file " << receiver_ssl_cert << endl;
      return -1;
    }
    if ((receiver_x = PEM_read_X509(f, NULL, NULL, NULL)) == NULL) {
      cout << "failed to read cert file " << receiver_ssl_cert << endl;
      fclose(f);
      return -1;
    }
    fclose(f);

    if ((f = fopen(receiver_ssl_key.c_str(), "r")) == NULL) {
      cout << "failed to open file " << receiver_ssl_key << endl;
      return -1;
    }
    if ((receiver_priv_key = PEM_read_RSAPrivateKey(f, NULL, NULL, NULL)) == NULL) {
      cout << "failed to read cert file " << receiver_ssl_key << endl;
      fclose(f);
      return -1;
    }
    fclose(f);
    /** ************************ READ FILES **************************** */
    /** **************************************************************** */

    /** **************************************************************** */
    /** *********************** GENERATE KEY *************************** */
    sender_evp_key = X509_get_pubkey(sender_x);

    PEM_write_bio_PUBKEY(bio, sender_evp_key);

    ret = BIO_read(bio, tmp_buf, 2000);

    ret = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha1(), NULL, tmp_buf, ret, 5, key, iv);
    if (ret != 32) {
      cout << "Key size is " << ret << " bytes, should be 256 bits" << endl;
      return -1;
    }
    /** *********************** GENERATE KEY *************************** */
    /** **************************************************************** */

    /** **************************************************************** */
    /** *********************** ENCRYPT KEY **************************** */
    sender_pub_key = EVP_PKEY_get1_RSA(sender_evp_key);

    unsigned char *encrypted_key = (unsigned char*)malloc(RSA_size(sender_pub_key) * sizeof(unsigned char));
    if ((ret = RSA_public_encrypt(32, key, encrypted_key, sender_pub_key, RSA_PKCS1_PADDING)) < 0) {
      cout << "RSA_public_encrypt failed: " << ERR_error_string(ERR_get_error(), NULL) << endl;
      return -1;
    }

    if ((ret = RSA_private_encrypt(ret, encrypted_key, encrypted_key, receiver_priv_key, RSA_NO_PADDING)) < 0) {
      cout << "RSA_private_encrypt failed, " << ERR_error_string(ERR_get_error(), NULL) << endl;
      return -1;
    }

    cout << "RSA_private_encrypt ret: " << ret << endl;
    /** *********************** ENCRYPT KEY **************************** */
    /** **************************************************************** */

    /** **************************************************************** */
    /** *********************** DECRYPT KEY **************************** */
    if ((receiver_evp_key = X509_get_pubkey(receiver_x)) == NULL) cout << "receiver_evp_key NULL" << endl;
    if ((receiver_pub_key = EVP_PKEY_get1_RSA(receiver_evp_key)) == NULL) cout << "receiver_pub_key NULL" << endl;

    unsigned char *decrypted_key = (unsigned char*)malloc(RSA_size(receiver_pub_key) * sizeof(unsigned char) + 1);
    if ((ret = RSA_public_decrypt(ret, encrypted_key, decrypted_key, receiver_pub_key, RSA_NO_PADDING)) < 0) {
      cout << "RSA_public_decrypt failed, " << ERR_error_string(ERR_get_error(), NULL) << endl;
      return -1;
    }
    cout << "RSA_public_decrypt ret: " << ret << endl;

    if ((ret = RSA_private_decrypt(ret, decrypted_key, decrypted_key, sender_priv_key, RSA_PKCS1_PADDING)) < 0) {
      cout << "RSA_private_decrypt failed, " << ERR_error_string(ERR_get_error(), NULL) << endl;
      return -1;
    }
    cout << "RSA_private_decrypt ret: " << ret << endl;

    /** *********************** DECRYPT KEY **************************** */
    /** **************************************************************** */

    return 0;
  }

编辑：在将strlen更改为由加密函数返回的ret值之后，这变成了okey 但是让我们转到第3步。将此代码添加到最后（在返回0;语句之前）

  /** **************************************************************** */
  /** ******************* ANOTHER ENCRYPT KEY ************************ */
  unsigned char *another_encrypted_key = (unsigned char*)malloc(RSA_size(receiver_pub_key) * sizeof(unsigned char));
  if ((ret = RSA_public_encrypt(32, decrypted_key, another_encrypted_key, receiver_pub_key, RSA_PKCS1_PADDING)) < 0) {
    cout << "RSA_public_encrypt failed: " << ERR_error_string(ERR_get_error(), NULL) << endl;
    return -1;
  }

  if ((ret = RSA_private_encrypt(ret, another_encrypted_key, another_encrypted_key, sender_priv_key, RSA_NO_PADDING)) < 0) {
    cout << "RSA_private_encrypt failed, " << ERR_error_string(ERR_get_error(), NULL) << endl;
    return -1;
  }

  /** ******************* ANOTHER ENCRYPT KEY ************************ */
  /** **************************************************************** */

这导致大约15％的机会获得：

error:04066084:rsa routines:RSA_EAY_PRIVATE_ENCRYPT:data too large for modulus

在RSA_private_encrypt上这是我努力的主要问题（之前的那个只是我的错误）

EDIT2：

RSA_public_encrypt ret: 128
RSA_size(sender_priv_key): 128
RSA_private_encrypt failed, error:04066084:rsa routines:RSA_EAY_PRIVATE_ENCRYPT:data too large for modulus

Answer 1

您的代码误用了strlen。 strlen函数只能用于C风格的字符串，而不能用于任意二进制数据。

文档指出RSA_private_encrypt和RSA_private_decrypt返回加密/解密数据的长度。但是你在strlen上调用encrypted_key 不是一个C风格的字符串 - 它只是一个没有简单结构的任意二进制数据块。

您无需在其上调用strlen，因为RSA_private_encrypt会返回其长度。并且无法在其上调用strlen，因为它不是字符串。

很多人对strlen（有时是sizeof）的行为都有错误的印象。它们具有精确定义的语义，您必须了解这些语义才能正确使用这些函数。他们并没有神奇地确定任意数据结构有多大。如果您没有特别知道某些内容是C风格的字符串，请不要将其传递给任何str*函数。

考虑一下 - 只有通过查看指向该数据第一个字节的指针，strlen可能实现哪种算法才能确定加密数据块的长度？你期待着魔法。

如何使用RSA正确交换对称的aes密钥

1 个答案: