#include <openssl/pkcs7.h>

              #include <openssl/objects.h>

             

              int    main()

              {

                     PKCS7                         *p7=NULL;

                     int                                ret,len;

                     char                      buf[1000],*p,name[1000];

                     FILE                            *fp;

             

             

                     fp=fopen("p7_sign.cer","rb");

                     len=fread(buf,1,1000,fp);

                     fclose(fp);

             

                     p=buf;

                     d2i_PKCS7(&p7,(const unsigned char **)&p,len);

                     ret=OBJ_obj2txt(name,1000,p7->type,0);

                     printf("type : %s \n",name);

                     PKCS7_free(p7);

                     return 0;

              }

              本例解码DER格式的PKCS7消息。