Extract issuer (CN) from SSL Certificate using openssl in iOS - iphone

Question

I want to extract Issuer CN (Common name) from SSL certificate using openSSL in iOS. I am using the link http://pastebin.com/Vn797Sc0 for extracting the information from the certificate. I am getting the issuer name but could not extract Issuer Common name(Common name) in iOS. Thanks in advance

Answer 1

You can extract the Common Name like the Organization field in the code you linked (Not tested)
static NSString * CertificateGetIssuerCommonName(X509 *certificateX509) {
NSString *issuerCN = nil;
if (certificateX509 != NULL) {
X509_NAME *issuerX509Name = X509_get_issuer_name(certificateX509);
if (issuerX509Name != NULL) {
int nid = OBJ_txt2nid("CN");
int index = X509_NAME_get_index_by_NID(issuerX509Name, nid, -1);
if (index != -1) {
X509_NAME_ENTRY *issuerNameCommonName = X509_NAME_get_entry(issuerX509Name, index);
if (issuerNameEntry) {
ASN1_STRING *issuerCNASN1 = X509_NAME_ENTRY_get_data(issuerNameEntry);
if (issuerCNASN1 != NULL) {
unsigned char *issuerCName = ASN1_STRING_data(issuerCNASN1);
issuerCN = [NSString stringWithUTF8String:(char *)issuerCName];
}
}
}
}
}
return issuerCN;
}

Answer 2

static NSString * CertificateGetIssuerName(X509 *certificateX509)
{
NSString *issuer = nil;
if (certificateX509 != NULL) {
X509_NAME *issuerX509Name = X509_get_issuer_name(certificateX509);
if (issuerX509Name != NULL) {
//NID_commonName extract the common name of the issuer
int index = X509_NAME_get_index_by_NID(issuerX509Name, NID_commonName, -1);
X509_NAME_ENTRY *issuerNameEntry = X509_NAME_get_entry(issuerX509Name, index);
if (issuerNameEntry) {
ASN1_STRING *issuerNameASN1 = X509_NAME_ENTRY_get_data(issuerNameEntry);
if (issuerNameASN1 != NULL) {
unsigned char *issuerName = ASN1_STRING_data(issuerNameASN1);
issuer = [NSString stringWithUTF8String:(char *)issuerName];
}
}
}
}
return issuer;
}