PKCS#12标准描述了个人标识信息的语法,一种交换数字证书的加密标准,包括用户公钥、私钥、证书等。Openssl提供了API供我们解析pfx/p12文件,提取我们需要的信息。

   首先我们需要了解几个数据结构,由于Openssl文档里面有些介绍的不是很详细,在这里列举一下:

   1、X509 struct

typedef struct x509_st X509;
struct x509_st
{
X509_CINF *cert_info;//证书主体信息
X509_ALGOR *sig_alg;//签名算法信息
ASN1_BIT_STRING *signature;//CA对证书的签名值
int valid;//是否是合法证书,1为合法,0为未知
int references;//引用次数,被引用一次则加一
char *name;//证书持有者信息,内容形式为/C=CN/O=ourinfo,该内容在调用d2i_X509的过程中,通过回调函数x509_cb(crypto/asn1/x_x509.c)调用X509_NAME_oneline来设置
CRYPTO_EX_DATA ex_data;//扩展数据结构,用于存放用户自定义的信息
/* These contain copies of various extension values */
long ex_pathlen;//证书路径长度,对应扩展项为NID_basic_constraints
long ex_pcpathlen;
unsigned long ex_flags;//通过“与”计算存放各种标记
unsigned long ex_kusage;//密钥用法,对应扩展项为NID_key_usage
unsigned long ex_xkusage;//扩展密钥用法,对应扩展项为NID_ext_key_usage
unsigned long ex_nscert;//Netscape证书类型,对应扩展项为NID_netscape_cert_type
ASN1_OCTET_STRING *skid;//主体密钥标识,对应扩展项为NID_subject_key_identifier
struct AUTHORITY_KEYID_st *akid;//颁发者密钥标识,对应扩展项为NID_authority_key_identifier
X509_POLICY_CACHE *policy_cache;//各种策略缓存,对应的策略为NID_policy_constraints、NID_certificate_policies、NID_policy_mappings和NID_inhibit_any_policy
#ifndef OPENSSL_NO_RFC3779
STACK_OF(IPAddressFamily) *rfc3779_addr;
struct ASIdentifiers_st *rfc3779_asid;
#endif
#ifndef OPENSSL_NO_SHA
unsigned char sha1_hash[SHA_DIGEST_LENGTH];//存放证书的sha1摘要值
#endif
X509_CERT_AUX *aux;//辅助信息
} /* X509 */;

 2、X509_CINF struct

typedef struct x509_cinf_st
{
ASN1_INTEGER *version;/* 证书版本,0代表V1,1代表V2 */
ASN1_INTEGER *serialNumber;//证书序列号
X509_ALGOR *signature;//签名算法
X509_NAME *issuer;//颁发者信息
X509_VAL *validity;//有效期
X509_NAME *subject;//拥有者信息
X509_PUBKEY *key;//拥有者的公钥
ASN1_BIT_STRING *issuerUID;/* [ 1 ] optional in v2 */
ASN1_BIT_STRING *subjectUID;/* [ 2 ] optional in v2 */
STACK_OF(X509_EXTENSION) *extensions;/* [ 3 ] optional in v3 */
} X509_CINF;

   3、EVP_PKEY struct

   

typedef struct evp_pkey_st EVP_PKEY;
typedef struct evp_pkey_st
{
     int type;
     int save_type;
     int references;
     union
     {
     char *ptr;//存放密钥结构地址
     #ifndef OPENSSL_NO_RSA
     struct rsa_st *rsa; /* RSA */
     #endif
     #ifndef OPENSSL_NO_DSA
     struct dsa_st *dsa; /* DSA */
     #endif
     #ifndef OPENSSL_NO_DH
     struct dh_st *dh; /* DH */
     #endif
     } pkey;
     int save_parameters;
     STACK_OF(X509_ATTRIBUTE) *attributes; /* [ 0 ] */ //存放密钥属性
    }EVP_PKEY;

  4、RSA struct

   

typedef struct rsa_st RSA;
struct rsa_st
{
    /* The first parameter is used to pickup errors where
     * this is passed instead of aEVP_PKEY, it is set to 0 */
    int pad;
    long version;
    const RSA_METHOD *meth;//RSA_METHOD结构,指明了本RSA密钥的各种运算函数地址
    /* functional reference if 'meth' is ENGINE-provided */
    ENGINE *engine;//硬件引擎
    BIGNUM *n;   //public modulus
    BIGNUM *e;    //public exponent
    BIGNUM *d;    //private exponent
    BIGNUM *p;    //secret prime factor
    BIGNUM *q;    //secret prime factor
    BIGNUM *dmp1;    //d mod (p-1)
    BIGNUM *dmq1;    //d mod (q-1)
    BIGNUM *iqmp;    //q^(-1) mod p
    /* be careful using this if the RSA structure is shared */
    CRYPTO_EX_DATA ex_data;//扩展数据结构,用于存放用户数据
    int references;//RSA结构引用数
    int flags;
    /* Used to cache montgomery values */
    BN_MONT_CTX *_method_mod_n;
    BN_MONT_CTX *_method_mod_p;
    BN_MONT_CTX *_method_mod_q;
    /* all BIGNUM values are actually in the following data, if it is not
     * NULL */
    char *bignum_data;
    BN_BLINDING *blinding;
    BN_BLINDING *mt_blinding;
};

   5、BIGNUM struct

   

typedef struct bignum_st BIGNUM;
struct bignum_st
{
       BN_ULONG *d;//BN_ULONG(应系统而异,win32下为4个字节)数组指针首地址,大数就存放在这里面,不过是倒放的
       int top;//用来指明大数占多少个BN_ULONG空间
       int dmax;//d数组的大小
       int neg;//是否为负数,如果为1,则是负数,为0,则为正数
       int flags;//用于存放一些标记,比如flags含有BN_FLG_STATIC_DATA时,表明d的内存是静态分配的;含有BN_FLG_MALLOCED时,d的内存是动态分配的
};

  6、STACK_OF struct

   

#define STACK_OF(type) STACK
typedef struct stack_st
{
      int num;//堆栈中存放数据的个数
      char **data;//用于存放数据地址,每个数据地址存放在data[0]到data[num-1]中
      int sorted;//堆栈是否已排序,如果排序则值为1,否则为0,堆栈数据一般是无序的,只有当用户调用了sk_sort操作,其值才为1
      int num_alloc;//
      int (*comp)(const char * const *, const char * const *);//堆栈内存放数据的比较函数地址,此函数用于排序和查找操作
} STACK;

  7、PKCS12 struct

typedef struct
{
ASN1_INTEGER *version;
PKCS12_MAC_DATA *mac;
PKCS7 *authsafes;
} PKCS12;

version为版本,mac用于存放MAC信息以及对称密钥相关的信息,authsafespkcs7结构,用于存放的证书、crl以及私钥等各种信息  

   下面是测试代码,先从PEM中提取信息保存到P12文件中,然后从p12中提取密钥用来加密和解密数据:

#include <stdio.h>
#include <stdlib.h>
#include <openssl/md5.h>   
#include <stdio.h> 
#include <openssl/rsa.h> 
#include <openssl/evp.h> 
#include <openssl/objects.h> 
#include <openssl/x509.h> 
#include <openssl/err.h> 
#include <openssl/pem.h> 
#include <openssl/pkcs12.h>  
#include <openssl/ssl.h> 
extern "C"
{
#include <openssl/applink.c>
}
#pragma comment(lib, "libeay32.lib")    
#pragma comment(lib, "ssleay32.lib")    
#define CERTS_FILE "mmm.pem"
#define CLNT_KEY CERTS_FILE
//使用*.p12作为扩展名会使得Windows操作系统正确认识和处理它
#define PKCS12_FILE "mao1.p12"
void print(const char *promptStr,unsigned char *data,int len )
{
    int i;
    printf("n==%s[输出长度=%d]=====n",promptStr,len);
    for(i = 0; i < len; i++)
    printf("%02x", data[i]);
    printf("n=======================n");
}
int main(int argc, char *argv[])
{
    X509 *cert_clnt,*cert_tmp;
    EVP_PKEY *pkey;
    EVP_PKEY *pkey_frompkcs12;
    STACK_OF(X509) *ca_chain=NULL;
    PKCS12 *pkcs12;
    FILE *fp;
    char* pass="123456";
    char* name="Client Private/Publication Key";
    char plainText[]="[For a test to read/write pkcs12 object]";
    unsigned char encData[512];
    char decData[512];
    int len=0;
    OpenSSL_add_all_algorithms();
    ERR_load_crypto_strings();
    //seed_prng();
    //读入私钥对象
    if ( NULL == (fp = fopen(CLNT_KEY, "r")) ||
        NULL == (pkey = PEM_read_PrivateKey(fp, NULL, NULL, NULL)))
    {
        printf("读客户端私钥出错");
        return -1;
    }
    rewind(fp);
    //读入证书链
    ca_chain = sk_X509_new_null();
    while(1)
    {
        //文件指针被移动,所以循环可以读取所有证书
        if ( NULL==(cert_tmp = PEM_read_X509(fp, NULL, NULL, NULL)))
        {
            break;
        }
        sk_X509_push(ca_chain, cert_tmp);
        if( 1==ca_chain->num )
        {
            cert_clnt=cert_tmp;//客户端证书
        }
    }
    fclose(fp);
    printf("%d个证书在证书文件%s中n",ca_chain->num,CERTS_FILE);
    if(ca_chain->num==0)
    {
        printf("没有证书在%sn",CERTS_FILE);
        return -1;
    }
      //ca_chain=NULL;
    //创建PKCS12对象
    pkcs12=PKCS12_create(
        pass, //对象保护口令
        name, //对象名称
        pkey, //要保护的私钥
        cert_clnt, //对应私钥的证书对象
        ca_chain, //用于验证证书的证书链
        0,0,0,0,0 //其它缺省或者未指定参数
        );
    if( NULL==pkcs12)
    {printf("创建PKCS12对象时出错");
    return -1;
    }
                                    
                                   
    //将对象写入文件
    if ( NULL == (fp = fopen(PKCS12_FILE, "w")) )
    {
        printf("以写方式打开文件%s时出错n",PKCS12_FILE);
        return -1;
    }
    if ( i2d_PKCS12_fp(fp,pkcs12) != 1)
    {printf("将pkcs12对象写入文件时出错n");
    return -1;
    }
                                        
                                   
    fclose(fp);
                                   
    if ( NULL == (fp = fopen(PKCS12_FILE, "r")) )
    {
        printf("以读方式打开文件%s时出错n",PKCS12_FILE);
        return -1;
    }
    if( NULL==(pkcs12=d2i_PKCS12_fp(fp, NULL)) )
    {printf("从文件中读pkcs12对象时出错"); 
    return -1;
    }
    sk_X509_pop_free(ca_chain,X509_free);
//  EVP_PKEY_free(pkey);//释放该公钥对象
    ca_chain=NULL;
    cert_clnt=NULL;
    //从PKCS12对象中解析出私钥,证书链,以及证书。
    //当然由于pkcs12对象受密码保护,所以要输入保护密码
    if( PKCS12_parse(pkcs12,pass, &pkey_frompkcs12,&cert_clnt,&ca_chain)!=1)
    {
        printf("解析pkcs12对象时出错"); 
        return -1;
    }
//  PKCS7 *authsafebag = pkcs12->authsafes;
//  STACK_OF(PKCS12_SAFEBAG)* pkcs12_safebag = PKCS12_unpack_p7data(authsafebag);
                                    
//  char* temp = sk_value(pkcs12_safebag,1);
//
//  PKCS12_SAFEBAG* pkcs12_temp = (PKCS12_SAFEBAG*)temp;
//  ASN1_OBJECT* type = pkcs12_temp->type;
//
//  int nsize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->n);
//  unsigned char* ndata = new unsigned char[nsize];
//
//  int ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->n,ndata);
//
//  int esize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->e);
//  unsigned char* edata = new unsigned char[esize];
//
//  ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->e,edata);
//  int dsize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->d);
//  unsigned char* ddata = new unsigned char[dsize];
//
//   ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->d,ddata);
//  int psize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->p);
//  unsigned char* pdata = new unsigned char[psize];
//
//  ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->p,pdata);
//  int qsize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->q);
//  unsigned char* qdata = new unsigned char[qsize];
//
//  ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->q,qdata);
//  int dmp1size = BN_num_bytes(pkey_frompkcs12->pkey.rsa->dmp1);
//  unsigned char* dmp1data = new unsigned char[dmp1size];
//
//  ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->dmp1,dmp1data);
//  int dmqsize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->dmq1);
//  unsigned char* dmq1data = new unsigned char[dmqsize];
//
//  ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->dmq1,dmq1data);
//  int idmpsize = BN_num_bytes(pkey_frompkcs12->pkey.rsa->iqmp);
//  unsigned char* iqmpdata = new unsigned char[idmpsize];
//
//  ret = BN_bn2bin(pkey_frompkcs12->pkey.rsa->iqmp,iqmpdata);
//
//  delete[] ndata;
//  delete[] edata;
//  delete[] ddata;
//  delete[] pdata;
//  delete[] qdata;
//  delete[] dmp1data;
//  delete[] dmq1data;
//  delete[] iqmpdata;
    printf("读取并解析pkcs12对象成功n pkcs 文件: n"
        " %sn 证书编号:%dn 证书名:%sn",
        PKCS12_FILE,ca_chain->num,cert_clnt->name);
    //利用解析出来的私钥去加密和解密
    len=EVP_PKEY_encrypt(encData,(const unsigned char*)plainText,
        sizeof(plainText),pkey_frompkcs12);
    if(len==-1)
    {printf("EVP_PKEY_encrypt失败"); 
    return -1;
    }
                                        
    print("加密后的数据是:",encData,len);
    //用公钥解密
    len=EVP_PKEY_decrypt((unsigned char*)
        decData,encData,len,pkey_frompkcs12);
    if(len==-1)
    {printf("EVP_PKEY_decrypt 失败"); 
    return -1;
    }
                                        
    //print("解密后的数据是:",(unsigned char *)decData,len);
    printf("n 明文是[长度=%d]:%sn",len,decData);
    printf("n click any key to continue.");getchar();
    return 0;
}