(Delphi DLL) 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 for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Xml, Csr, BinData, PrivateKey, PublicKey, Prng, Ecc;

...

procedure TForm1.Button1Click(Sender: TObject);
var
ecc: HCkEcc;
prng: HCkPrng;
privKey: HCkPrivateKey;
csr: HCkCsr;
s: PWideChar;
bdTemp: HCkBinData;
s_base64_utf16be: PWideChar;
xml: HCkXml;
pubKey: HCkPublicKey;
bdPubKeyDer: HCkBinData;
ski: PWideChar;
csrPem: PWideChar;

begin
// 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 := CkEcc_GenEccKey(ecc,'secp256r1',prng);
if (CkEcc_getLastMethodSuccess(ecc) = False) then
  begin
    Memo1.Lines.Add('Failed to generate a new ECDSA private key.');
    Exit;
  end;

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....."
Memo1.Lines.Add(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 := CkPrivateKey_GetPublicKey(privKey);
bdPubKeyDer := CkBinData_Create();
CkBinData_AppendEncoded(bdPubKeyDer,CkPublicKey__getEncoded(pubKey,True,'base64'),'base64');
ski := CkBinData__getHash(bdPubKeyDer,'sha1','base64');
CkPublicKey_Dispose(pubKey);

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) then
  begin
    Memo1.Lines.Add(CkCsr__lastErrorText(csr));
    CkPrivateKey_Dispose(privKey);
    Exit;
  end;

Memo1.Lines.Add(csrPem);

CkPrivateKey_Dispose(privKey);

CkEcc_Dispose(ecc);
CkPrng_Dispose(prng);
CkCsr_Dispose(csr);
CkBinData_Dispose(bdTemp);
CkXml_Dispose(xml);
CkBinData_Dispose(bdPubKeyDer);

end;