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POASN1_INTEGER to ASN1_STRING
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copied!<p>I am using openssl to get data about x509 certificate. Is there a way to convert ASN1_INTEGER to ASN1_STRING, which can than easily be transformed to char array? Is there a way to convert it to any other human readable format?</p> <p>EDIT: I'm using openssl compiled for iOS, as I am having the iOS project. Here is the code I am using to extract the serial number from the certificate:</p> <pre><code>ASN1_INTEGER *serial = X509_get_serialNumber(certificateX509); long value = ASN1_INTEGER_get(serial); NSLog(@"Serial %ld", value); </code></pre> <p><code>certificateX509</code> is a valid X509 object and I have managed to get some other fields from it (issuer name, expiry date and so on)</p> <p>EDIT 2:<br> I finally came to a solution, which may not be the most straightforward one:</p> <pre><code> ASN1_INTEGER *serial = X509_get_serialNumber(certificateX509); BIGNUM *bnser = ASN1_INTEGER_to_BN(serial, NULL); int n = BN_num_bytes(bnser); unsigned char outbuf[n]; int bin = BN_bn2bin(bnser, outbuf); char *hexbuf = (char*) outbuf; </code></pre> <p>hexBuf then contains characters whose value needs to be read as hex integer in order to retrieve logical values. I use NSMutableString to create a human readable string:</p> <pre><code>NSMutableString *str = [[NSMutableString alloc] init]; for (int i=0; i<n; i++) { NSString *temp = [NSString stringWithFormat:@"%.6x", hexbuf[i]]; [str appendString:[NSString stringWithFormat:@"%@ ", temp]]; } </code></pre> <p>If there is a simpler way, I would really like to know it.</p>

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