Openssl（版本1.1.1）源码中的RSA加解密算法实现分析

最新推荐文章于 2024-10-28 10:00:06 发布

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最新推荐文章于 2024-10-28 10:00:06 发布 · 5.5k 阅读

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#openssl #RSA

使用的源码版本:1.1.1 下载地址：https://www.openssl.org/source/

参考了博文：https://blog.youkuaiyun.com/xsc_c/article/details/37742019?fps=1&locationNum=14，但是由于版本不一样，实现细节有些不同。

1. 首先在crypto/rsa文件夹下找到rsa_crpt.c文件，加解密上层函数所在位置

int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
                       RSA *rsa, int padding)
{
    return rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding);
}

int RSA_private_encrypt(int flen, const unsigned char *from,
                        unsigned char *to, RSA *rsa, int padding)
{
    return rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding);
}

int RSA_private_decrypt(int flen, const unsigned char *from,
                        unsigned char *to, RSA *rsa, int padding)
{
    return rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding);
}

int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
                       RSA *rsa, int padding)
{
    return rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding);
}

2. 在同文件夹下的rsa_locl.h中，我们可以看设置对应的方法地址指针。

struct rsa_meth_st {
    char *name;
    int (*rsa_pub_enc) (int flen, const unsigned char *from,
                        unsigned char *to, RSA *rsa, int padding);
    int (*rsa_pub_dec) (int flen, const unsigned char *from,
                        unsigned char *to, RSA *rsa, int padding);
    int (*rsa_priv_enc) (int flen, const unsigned char *from,
                         unsigned char *to, RSA *rsa, int padding);
    int (*rsa_priv_dec) (int flen, const unsigned char *from,
                         unsigned char *to, RSA *rsa, int padding);
    /* Can be null */
    int (*rsa_mod_exp) (BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx);
    /* Can be null */
    int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, c