以編程方式使用openssl提取pem證書信息

Question

使用openssl命令行可以以人類可讀模式提取.pem證書中包含的所有信息;那就是：

openssl x509 -noout -in <MyCertificate>.pem -text 

什麼是適當的步驟，以便使用openssl API提取這些信息？

問候，

Answer 1

的X509_print_ex家庭的功能是你的答案。

#include <openssl/x509.h> 
#include <openssl/pem.h> 
#include <openssl/bio.h> 

int main(int argc, char **argv) 
{ 
    X509 *x509; 
    BIO *i = BIO_new(BIO_s_file()); 
    BIO *o = BIO_new_fp(stdout,BIO_NOCLOSE); 

    if((argc < 2) || 
     (BIO_read_filename(i, argv[1]) <= 0) || 
     ((x509 = PEM_read_bio_X509_AUX(i, NULL, NULL, NULL)) == NULL)) { 
     return -1; 
    } 

    X509_print_ex(o, x509, XN_FLAG_COMPAT, X509_FLAG_COMPAT); 
} 

Answer 2

作爲與此問題相關的附加信息，如果有DER格式而不是PEM證書;還可以使用以下代碼在人類可讀模式下提取信息：

//Assuming that the DER certificate binary information is stored in 
//a byte array (unsigned char) called "pData" whose size is "lenData" 
X509* x509; 
BIO* input = BIO_new_mem_buf((void*)pData, lenData); 
//d2i_X509_bio: Decodes the binary DER certificate 
//and parses it to a X509 structure 
x509 = d2i_X509_bio(input, NULL); 
if (x509 == NULL) 
{ 
    //Error in d2i_X509_bio 
} 
else 
{ 
    //"certificateFile" is the full path file 
    //where to store the certificate information 
    //in a human readable mode (instead of stdout) 
    FILE* fd = fopen(certificateFile, "w+"); 
    BIO* output = BIO_new_fp(fd, BIO_NOCLOSE); 
    X509_print_ex(output, x509, XN_FLAG_COMPAT, X509_FLAG_COMPAT); 
    fclose(fd); 
    BIO_free_all(output); 
} 
BIO_free_all(input);