(Perl) 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 Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

# 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 = chilkat::CkEcc->new();
$prng = chilkat::CkPrng->new();

# privKey is a PrivateKey
$privKey = $ecc->GenEccKey("secp256r1",$prng);
if ($ecc->get_LastMethodSuccess() == 0) {
    print "Failed to generate a new ECDSA private key." . "\r\n";
    exit;
}

$csr = chilkat::CkCsr->new();

# Add common CSR fields:
$csr->put_CommonName("mysubdomain.mydomain.com");
$csr->put_Country("GB");
$csr->put_State("Yorks");
$csr->put_Locality("York");
$csr->put_Company("Internet Widgits Pty Ltd");
$csr->put_EmailAddress('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 = chilkat::CkBinData->new();
$bdTemp->AppendString($s,"utf-16be");
$s_base64_utf16be = $bdTemp->getEncoded("base64");
# The string should be "AEUA....."
print $s_base64_utf16be . "\r\n";

# Here's the code to generate the above extension request.

$xml = chilkat::CkXml->new();
$xml->put_Tag("set");
$xml->UpdateChildContent("sequence|sequence|oid","1.3.6.1.4.1.311.20.2");
$xml->UpdateAttrAt("sequence|sequence|asnOctets|universal",1,"tag","30");
$xml->UpdateAttrAt("sequence|sequence|asnOctets|universal",1,"constructed","0");
$xml->UpdateChildContent("sequence|sequence|asnOctets|universal",$s_base64_utf16be);
$xml->UpdateChildContent("sequence|sequence[1]|oid","2.5.29.15");
$xml->UpdateChildContent("sequence|sequence[1]|bool","1");
$xml->UpdateAttrAt("sequence|sequence[1]|asnOctets|bits",1,"n","3");
# A0 is hex for decimal 160.
$xml->UpdateChildContent("sequence|sequence[1]|asnOctets|bits","A0");
$xml->UpdateChildContent("sequence|sequence[2]|oid","2.5.29.37");
$xml->UpdateChildContent("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 is a PublicKey
$pubKey = $privKey->GetPublicKey();
$bdPubKeyDer = chilkat::CkBinData->new();
$bdPubKeyDer->AppendEncoded($pubKey->getEncoded(1,"base64"),"base64");
$ski = $bdPubKeyDer->getHash("sha1","base64");

$xml->UpdateChildContent("sequence|sequence[3]|oid","2.5.29.14");
$xml->UpdateChildContent("sequence|sequence[3]|asnOctets|octets",$ski);

# Add the extension request to the CSR
$csr->SetExtensionRequest($xml);

# Generate the CSR with the extension request
$csrPem = $csr->genCsrPem($privKey);
if ($csr->get_LastMethodSuccess() == 0) {
    print $csr->lastErrorText() . "\r\n";

    exit;
}

print $csrPem . "\r\n";