(Tcl) 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

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load ./chilkat.dll

# 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.
set ecc [new_CkEcc]

set prng [new_CkPrng]

# privKey is a CkPrivateKey
set privKey [CkEcc_GenEccKey $ecc "secp256r1" $prng]
if {[CkEcc_get_LastMethodSuccess $ecc] == 0} then {
    puts "Failed to generate a new ECDSA private key."
    delete_CkEcc $ecc
    delete_CkPrng $prng
    exit
}

set csr [new_CkCsr]

# Add common CSR fields:
CkCsr_put_CommonName $csr "mysubdomain.mydomain.com"
CkCsr_put_Country $csr "GB"
CkCsr_put_State $csr "Yorks"
CkCsr_put_Locality $csr "York"
CkCsr_put_Company $csr "Internet Widgits Pty Ltd"
CkCsr_put_EmailAddress $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"

set s "EndEntityClientAuthCertificate_CSRPassthrough/V1"
set bdTemp [new_CkBinData]

CkBinData_AppendString $bdTemp $s "utf-16be"
set s_base64_utf16be [CkBinData_getEncoded $bdTemp "base64"]
# The string should be "AEUA....."
puts "$s_base64_utf16be"

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

set xml [new_CkXml]

CkXml_put_Tag $xml "set"
CkXml_UpdateChildContent $xml "sequence|sequence|oid" "1.3.6.1.4.1.311.20.2"
CkXml_UpdateAttrAt $xml "sequence|sequence|asnOctets|universal" 1 "tag" "30"
CkXml_UpdateAttrAt $xml "sequence|sequence|asnOctets|universal" 1 "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" 1 "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 is a CkPublicKey
set pubKey [CkPrivateKey_GetPublicKey $privKey]
set bdPubKeyDer [new_CkBinData]

CkBinData_AppendEncoded $bdPubKeyDer [CkPublicKey_getEncoded $pubKey 1 "base64"] "base64"
set ski [CkBinData_getHash $bdPubKeyDer "sha1" "base64"]
delete_CkPublicKey $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
set csrPem [CkCsr_genCsrPem $csr $privKey]
if {[CkCsr_get_LastMethodSuccess $csr] == 0} then {
    puts [CkCsr_lastErrorText $csr]
    delete_CkPrivateKey $privKey

    delete_CkEcc $ecc
    delete_CkPrng $prng
    delete_CkCsr $csr
    delete_CkBinData $bdTemp
    delete_CkXml $xml
    delete_CkBinData $bdPubKeyDer
    exit
}

puts "$csrPem"

delete_CkPrivateKey $privKey


delete_CkEcc $ecc
delete_CkPrng $prng
delete_CkCsr $csr
delete_CkBinData $bdTemp
delete_CkXml $xml
delete_CkBinData $bdPubKeyDer