c语言写成的取x.509证书公钥

#include "stdio.h" #include "iostream.h" #include "string" #include "math.h" using namespace std; enum classification { universal, application, context_specific, privateclass }; enum constructed { simplecon, constructed }; //程序中未使用 enum type { boolean=1 ,//[有两个值:false或true] interger, //[整型值] BitString, //[0位或多位] OctetString,//[0字节或多字节] null, ObejectIdentifier, //[相应于一个对象的独特标识数字] ObjectDescriptor, //[一个对象的简称] External,// [ASN.1没有定义的数据类型] Real,//[实数值] Enumerated,//[数值列表，这些数据每个都有独特的标识符，作为ASN.1定义数据类型的一部分] UTF8String, Relative_oid, Sequence,//[有序数列，SEQUENCE里面的每个数值都可以是不同类型的，而SEQUENCE OF里是0个或多个类型相同的数据] Set, // [无序数列，SET里面的每个数值都可以是不同类型的，而SET OF里是0个或多个类型相同的数据] NumericString,//[0－9以及空格] PrintableString,//[A-Z、a-z、0-9、空格以及符号'()+,-./:=?] TeletexString,//T61String VideotexString, IA5String, UTCTime, //[统一全球时间格式] GeneralizedTime, GraphicString, VisibleString, //ISO646String GeneralString, UniversalString, CharaterString, BMPString, reserved , version, issuerUniqueID, subjectUniqueID, external }; int gettype(FILE* cfile ) { //取byte第8,7位数值判断 classification unsigned char byte =fgetc(cfile); int theclass=0,thetype=0; theclass=byte>>6; thetype=(byte&31); if(context_specific==theclass) { return 32+thetype; } else { return thetype; } } bool IsMulti(unsigned char byte) { return (bool)(byte>>7); } int getSignlength(unsigned char byte) { return byte&127; } int ConvertByteToNum(unsigned char* pByte,int len) { int i=0, tmp, result=0; for(i=0;i<len;i++) { tmp=pByte[len-i-1]*pow(256,i); result+=tmp; } return result; } int getLength(FILE* cfile) { unsigned char byte =fgetc(cfile); int len=getSignlength(byte); if(IsMulti(byte)) { unsigned char* pByte=new unsigned char[len]; fread(pByte,1,len,cfile); len=ConvertByteToNum(pByte,len); delete pByte; return len; } else { return len; } } void getTypeandLen(FILE* cfile,int& thetype,int& len) { thetype=gettype(cfile); len=getLength(cfile); } void getversion(int ver) { if(0x00==ver) {cout<<"证书版本为：v1"<<endl;} else if(0x01==ver) {cout<<"证书版本为：v2"<<endl;} else if(0x02==ver) {cout<<"证书版本为：v3"<<endl;} } #define MAX_LEN 10000 #define MAX_PATH 256 void main() { FILE* cfile; char strpath[MAX_PATH]; cin>>strpath; cfile=fopen(strpath,"rb+"); if(cfile==NULL) { cout<<"open cert fail"<<endl; return; } int thetype=0,tmpint=-1,len=0; int namelen=0; unsigned char* pByte=NULL; //获取证书长度字节 getTypeandLen(cfile,thetype,len); cout<<"证书长度为："<<len<<"字节"<<endl; //获取证书主体长度字节 getTypeandLen(cfile,thetype,len); cout<<"证书主体长度为："<<len<<"字节"<<endl; //获取版本号 getTypeandLen(cfile,thetype,len); if(32==thetype) { cout<<"证书版本长度为："<<len<<"字节"<<endl; getTypeandLen(cfile,thetype,len); pByte=new unsigned char[len]; fread(pByte,1,len,cfile); tmpint=ConvertByteToNum(pByte,len); getversion(tmpint); delete[] pByte; } //获取版本序列号 getTypeandLen(cfile,thetype,len); pByte=new unsigned char[len]; fread(pByte,1,len,cfile); tmpint=ConvertByteToNum(pByte,len); delete[] pByte; cout<<"证书序列号为"<<tmpint<<endl; //跳过算法签名 getTypeandLen(cfile,thetype,len); namelen=len; //保留算法签名 fseek(cfile,len,SEEK_CUR); //跳过 issuer name getTypeandLen(cfile,thetype,len); fseek(cfile,len,SEEK_CUR); //跳过 证书有效期 getTypeandLen(cfile,thetype,len); fseek(cfile,len,SEEK_CUR); //跳过 证书主体名称 getTypeandLen(cfile,thetype,len); fseek(cfile,len,SEEK_CUR); //获取公钥 getTypeandLen(cfile,thetype,len); fseek(cfile,namelen+2,SEEK_CUR); getTypeandLen(cfile,thetype,len); pByte=new unsigned char[len]; fread(pByte,1,len,cfile); fclose(cfile); for(int i=0;i<len-1;i++) { unsigned char tmpchar=pByte[i]; printf("ox%X ",tmpchar); } cout<<endl; delete[] pByte; }