C
C
Generate a CSR with keyUsage, extKeyUsage, and other Extensions
See more CSR Examples
Demonstrates how to generate a CSR containing a 1.2.840.113549.1.9.14 extensionRequest with the following extensions:- 1.3.6.1.4.1.311.20.2 enrollCerttypeExtension
- 2.5.29.15 keyUsage
- 2.5.29.37 extKeyUsage
- 2.5.29.14 subjectKeyIdentifier
Chilkat C Downloads
#include <C_CkEcc.h>
#include <C_CkPrng.h>
#include <C_CkPrivateKey.h>
#include <C_CkCsr.h>
#include <C_CkBinData.h>
#include <C_CkXml.h>
#include <C_CkPublicKey.h>
void ChilkatSample(void)
{
BOOL success;
HCkEcc ecc;
HCkPrng prng;
HCkPrivateKey privKey;
HCkCsr csr;
const char *s;
HCkBinData bdTemp;
const char *s_base64_utf16be;
HCkXml xml;
HCkPublicKey pubKey;
HCkBinData bdPubKeyDer;
const char *ski;
const char *csrPem;
success = FALSE;
// This requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
// This example will generate a secp256r1 ECDSA key for the CSR.
ecc = CkEcc_Create();
prng = CkPrng_Create();
privKey = CkPrivateKey_Create();
success = CkEcc_GenKey(ecc,"secp256r1",prng,privKey);
if (success == FALSE) {
printf("Failed to generate a new ECDSA private key.\n");
CkEcc_Dispose(ecc);
CkPrng_Dispose(prng);
CkPrivateKey_Dispose(privKey);
return;
}
csr = CkCsr_Create();
// Add common CSR fields:
CkCsr_putCommonName(csr,"mysubdomain.mydomain.com");
CkCsr_putCountry(csr,"GB");
CkCsr_putState(csr,"Yorks");
CkCsr_putLocality(csr,"York");
CkCsr_putCompany(csr,"Internet Widgits Pty Ltd");
CkCsr_putEmailAddress(csr,"support@mydomain.com");
// Add the following 1.2.840.113549.1.9.14 extensionRequest
// Note: The easiest way to know the content and format of the XML to be added is to examine
// a pre-existing CSR with the same desired extensionRequest. You can use Chilkat to
// get the extensionRequest from an existing CSR.
//
// Here is a sample extension request:
// <?xml version="1.0" encoding="utf-8"?>
// <set>
// <sequence>
// <sequence>
// <oid>1.3.6.1.4.1.311.20.2</oid>
// <asnOctets>
// <universal tag="30" constructed="0">AEUAbgBkAEUAbgB0AGkAdAB5AEMAbABpAGUAbgB0AEEAdQB0AGgAQwBlAHIAdABpAGYAaQBjAGEAdABl
// AF8AQwBTAFIAUABhAHMAcwB0AGgAcgBvAHUAZwBoAC8AVgAx</universal>
// </asnOctets>
// </sequence>
// <sequence>
// <oid>2.5.29.15</oid>
// <bool>1</bool>
// <asnOctets>
// <bits n="3">A0</bits>
// </asnOctets>
// </sequence>
// <sequence>
// <oid>2.5.29.37</oid>
// <asnOctets>
// <sequence>
// <oid>1.3.6.1.5.5.7.3.3</oid>
// </sequence>
// </asnOctets>
// </sequence>
// <sequence>
// <oid>2.5.29.14</oid>
// <asnOctets>
// <octets>MCzBMQAViXBz8IDt8LsgmJxJ4Xg=</octets>
// </asnOctets>
// </sequence>
// </sequence>
// </set>
// Use this online tool to generate code from sample XML:
// Generate Code to Create XML
// A few notes:
// The string "AEUAbgBkAEUAbgB0AGkAdAB5AEMAbABpAGUAbgB0AEEAdQB0AGgAQwBlAHIAdABpAGYAaQBjAGEAdABlAF8AQwBTAFIAUABhAHMAcwB0AGgAcgBvAHUAZwBoAC8AVgAx"
// is the base64 encoding of the utf-16be byte representation of the string "EndEntityClientAuthCertificate_CSRPassthrough/V1"
s = "EndEntityClientAuthCertificate_CSRPassthrough/V1";
bdTemp = CkBinData_Create();
CkBinData_AppendString(bdTemp,s,"utf-16be");
s_base64_utf16be = CkBinData_getEncoded(bdTemp,"base64");
// The string should be "AEUA....."
printf("%s\n",s_base64_utf16be);
// Here's the code to generate the above extension request.
xml = CkXml_Create();
CkXml_putTag(xml,"set");
CkXml_UpdateChildContent(xml,"sequence|sequence|oid","1.3.6.1.4.1.311.20.2");
CkXml_UpdateAttrAt(xml,"sequence|sequence|asnOctets|universal",TRUE,"tag","30");
CkXml_UpdateAttrAt(xml,"sequence|sequence|asnOctets|universal",TRUE,"constructed","0");
CkXml_UpdateChildContent(xml,"sequence|sequence|asnOctets|universal",s_base64_utf16be);
CkXml_UpdateChildContent(xml,"sequence|sequence[1]|oid","2.5.29.15");
CkXml_UpdateChildContent(xml,"sequence|sequence[1]|bool","1");
CkXml_UpdateAttrAt(xml,"sequence|sequence[1]|asnOctets|bits",TRUE,"n","3");
// A0 is hex for decimal 160.
CkXml_UpdateChildContent(xml,"sequence|sequence[1]|asnOctets|bits","A0");
CkXml_UpdateChildContent(xml,"sequence|sequence[2]|oid","2.5.29.37");
CkXml_UpdateChildContent(xml,"sequence|sequence[2]|asnOctets|sequence|oid","1.3.6.1.5.5.7.3.3");
// This is the subjectKeyIdentifier extension.
// The string "MCzBMQAViXBz8IDt8LsgmJxJ4Xg=" is base64 that decodes to 20 bytes, which is a SHA1 hash.
// This is simply a hash of the DER of the public key.
pubKey = CkPublicKey_Create();
CkPrivateKey_ToPublicKey(privKey,pubKey);
bdPubKeyDer = CkBinData_Create();
CkBinData_AppendEncoded(bdPubKeyDer,CkPublicKey_getEncoded(pubKey,TRUE,"base64"),"base64");
ski = CkBinData_getHash(bdPubKeyDer,"sha1","base64");
CkXml_UpdateChildContent(xml,"sequence|sequence[3]|oid","2.5.29.14");
CkXml_UpdateChildContent(xml,"sequence|sequence[3]|asnOctets|octets",ski);
// Add the extension request to the CSR
CkCsr_SetExtensionRequest(csr,xml);
// Generate the CSR with the extension request
csrPem = CkCsr_genCsrPem(csr,privKey);
if (CkCsr_getLastMethodSuccess(csr) == FALSE) {
printf("%s\n",CkCsr_lastErrorText(csr));
CkEcc_Dispose(ecc);
CkPrng_Dispose(prng);
CkPrivateKey_Dispose(privKey);
CkCsr_Dispose(csr);
CkBinData_Dispose(bdTemp);
CkXml_Dispose(xml);
CkPublicKey_Dispose(pubKey);
CkBinData_Dispose(bdPubKeyDer);
return;
}
printf("%s\n",csrPem);
CkEcc_Dispose(ecc);
CkPrng_Dispose(prng);
CkPrivateKey_Dispose(privKey);
CkCsr_Dispose(csr);
CkBinData_Dispose(bdTemp);
CkXml_Dispose(xml);
CkPublicKey_Dispose(pubKey);
CkBinData_Dispose(bdPubKeyDer);
}