Openssl解析私pfx/p12證書(1)

   PKCS#12標準描述了個人標識信息的語法，一種交換數字證書的加密標準，包括用戶公鑰、私鑰、證書等。Openssl提供了API供我們解析pfx/p12文件，提取我們需要的信息。

   首先我們需要了解幾個數據結構，由於Openssl文檔裏面有些介紹的不是很詳細，在這裏列舉一下：

   1、X509 struct

typedef struct x509_st X509;
struct x509_st
{
X509_CINF *cert_info;//證書主體信息
X509_ALGOR *sig_alg;//簽名算法信息
ASN1_BIT_STRING *signature;//CA對證書的簽名值
int valid;//是否是合法證書，1爲合法，0爲未知
int references;//引用次數，被引用一次則加一
char *name;//證書持有者信息，內容形式爲/C=CN/O=ourinfo，該內容在調用d2i_X509的過程中，通過回調函數x509_cb(crypto/asn1/x_x509.c)調用X509_NAME_oneline來設置
CRYPTO_EX_DATA ex_data;//擴展數據結構，用於存放用戶自定義的信息
/* These contain copies of various extension values */
long ex_pathlen;//證書路徑長度，對應擴展項爲NID_basic_constraints
long ex_pcpathlen;
unsigned long ex_flags;//通過“與”計算存放各種標記
unsigned long ex_kusage;//密鑰用法，對應擴展項爲NID_key_usage
unsigned long ex_xkusage;//擴展密鑰用法，對應擴展項爲NID_ext_key_usage
unsigned long ex_nscert;//Netscape證書類型，對應擴展項爲NID_netscape_cert_type
ASN1_OCTET_STRING *skid;//主體密鑰標識，對應擴展項爲NID_subject_key_identifier
struct AUTHORITY_KEYID_st *akid;//頒發者密鑰標識，對應擴展項爲NID_authority_key_identifier
X509_POLICY_CACHE *policy_cache;//各種策略緩存，對應的策略爲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];//存放證書的sha1摘要值
#endif
X509_CERT_AUX *aux;//輔助信息
} /* X509 */;

 2、X509_CINF struct

typedef struct x509_cinf_st
{
ASN1_INTEGER *version;/* 證書版本，0代表V1，1代表V2 */
ASN1_INTEGER *serialNumber;//證書序列號
X509_ALGOR *signature;//簽名算法
X509_NAME *issuer;//頒發者信息
X509_VAL *validity;//有效期
X509_NAME *subject;//擁有者信息
X509_PUBKEY *key;//擁有者的公鑰
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;//存放密鑰結構地址
     #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 ] */ //存放密鑰屬性
    }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結構，指明瞭本RSA密鑰的各種運算函數地址
    /* 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;//擴展數據結構，用於存放用戶數據
    int references;//RSA結構引用數
    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(應系統而異，win32下爲4個字節)數組指針首地址，大數就存放在這裏面，不過是倒放的
       int top;//用來指明大數佔多少個BN_ULONG空間
       int dmax;//d數組的大小
       int neg;//是否爲負數，如果爲1，則是負數，爲0，則爲正數
       int flags;//用於存放一些標記，比如flags含有BN_FLG_STATIC_DATA時，表明d的內存是靜態分配的；含有BN_FLG_MALLOCED時，d的內存是動態分配的
};

  6、STACK_OF struct

   

#define STACK_OF(type) STACK
typedef struct stack_st
{
      int num;//堆棧中存放數據的個數
      char **data;//用於存放數據地址，每個數據地址存放在data[0]到data[num-1]中
      int sorted;//堆棧是否已排序，如果排序則值爲1，否則爲0，堆棧數據一般是無序的，只有當用戶調用了sk_sort操作，其值才爲1
      int num_alloc;//
      int (*comp)(const char * const *, const char * const *);//堆棧內存放數據的比較函數地址，此函數用於排序和查找操作
} STACK;

  7、PKCS12 struct

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

version爲版本，mac用於存放MAC信息以及對稱密鑰相關的信息，authsafes爲pkcs7結構，用於存放的證書、crl以及私鑰等各種信息  

   下面是測試代碼，先從PEM中提取信息保存到P12文件中，然後從p12中提取密鑰用來加密和解密數據：

#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作爲擴展名會使得Windows操作系統正確認識和處理它
#define PKCS12_FILE "mao1.p12"
void print(const char *promptStr,unsigned char *data,int len )
{
    int i;
    printf("n==%s[輸出長度=%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();
    //讀入私鑰對象
    if ( NULL == (fp = fopen(CLNT_KEY, "r")) ||
        NULL == (pkey = PEM_read_PrivateKey(fp, NULL, NULL, NULL)))
    {
        printf("讀客戶端私鑰出錯");
        return -1;
    }
    rewind(fp);
    //讀入證書鏈
    ca_chain = sk_X509_new_null();
    while(1)
    {
        //文件指針被移動，所以循環可以讀取所有證書
        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;//客戶端證書
        }
    }
    fclose(fp);
    printf("%d個證書在證書文件%s中n",ca_chain->num,CERTS_FILE);
    if(ca_chain->num==0)
    {
        printf("沒有證書在%sn",CERTS_FILE);
        return -1;
    }
      //ca_chain=NULL;
    //創建PKCS12對象
    pkcs12=PKCS12_create(
        pass, //對象保護口令
        name, //對象名稱
        pkey, //要保護的私鑰
        cert_clnt, //對應私鑰的證書對象
        ca_chain, //用於驗證證書的證書鏈
        0,0,0,0,0 //其它缺省或者未指定參數
        );
    if( NULL==pkcs12)
    {printf("創建PKCS12對象時出錯");
    return -1;
    }
                                    
                                   
    //將對象寫入文件
    if ( NULL == (fp = fopen(PKCS12_FILE, "w")) )
    {
        printf("以寫方式打開文件%s時出錯n",PKCS12_FILE);
        return -1;
    }
    if ( i2d_PKCS12_fp(fp,pkcs12) != 1)
    {printf("將pkcs12對象寫入文件時出錯n");
    return -1;
    }
                                        
                                   
    fclose(fp);
                                   
    if ( NULL == (fp = fopen(PKCS12_FILE, "r")) )
    {
        printf("以讀方式打開文件%s時出錯n",PKCS12_FILE);
        return -1;
    }
    if( NULL==(pkcs12=d2i_PKCS12_fp(fp, NULL)) )
    {printf("從文件中讀pkcs12對象時出錯"); 
    return -1;
    }
    sk_X509_pop_free(ca_chain,X509_free);
//  EVP_PKEY_free(pkey);//釋放該公鑰對象
    ca_chain=NULL;
    cert_clnt=NULL;
    //從PKCS12對象中解析出私鑰，證書鏈，以及證書。
    //當然由於pkcs12對象受密碼保護，所以要輸入保護密碼
    if( PKCS12_parse(pkcs12,pass, &pkey_frompkcs12,&cert_clnt,&ca_chain)!=1)
    {
        printf("解析pkcs12對象時出錯"); 
        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("讀取並解析pkcs12對象成功n pkcs 文件: n"
        " %sn 證書編號:%dn 證書名:%sn",
        PKCS12_FILE,ca_chain->num,cert_clnt->name);
    //利用解析出來的私鑰去加密和解密
    len=EVP_PKEY_encrypt(encData,(const unsigned char*)plainText,
        sizeof(plainText),pkey_frompkcs12);
    if(len==-1)
    {printf("EVP_PKEY_encrypt失敗"); 
    return -1;
    }
                                        
    print("加密後的數據是：",encData,len);
    //用公鑰解密
    len=EVP_PKEY_decrypt((unsigned char*)
        decData,encData,len,pkey_frompkcs12);
    if(len==-1)
    {printf("EVP_PKEY_decrypt 失敗"); 
    return -1;
    }
                                        
    //print("解密後的數據是：",(unsigned char *)decData,len);
    printf("n 明文是[長度=%d]:%sn",len,decData);
    printf("n click any key to continue.");getchar();
    return 0;
}