(Tcl) Duplicate openssl req -newkey rsa:2048 -nodes -keyout mydomain.pem -out mydomain.csr

Demonstrates how to duplicate this OpenSSL command:

openssl req -newkey rsa:2048 -nodes -keyout mydomain.pem -out mydomain.csr

This command creates 2 files:

mydomain.csr: this is the file to send to DigiCert or Let's Encrypt (or any other CA)
mydomain.pem: this is the private key of the domain.

The second file is needed to pair with the certificate that will later be received from the CA.

Chilkat Tcl Extension Downloads

Chilkat Tcl Extension Downloads

load ./chilkat.dll

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

set rsa [new_CkRsa]

# Generate a 2048-bit key.  Chilkat RSA supports
# key sizes ranging from 512 bits to 8192 bits.
set success [CkRsa_GenerateKey $rsa 2048]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkRsa $rsa
    exit
}

# privKey is a CkPrivateKey
set privKey [CkRsa_ExportPrivateKeyObj $rsa]

# Save the private key to unencrypted PKCS8 PEM
set success [CkPrivateKey_SavePkcs8PemFile $privKey "mydomain.pem"]

# (alternatively) Save the private key to encrypted PKCS8 PEM
set success [CkPrivateKey_SavePkcs8EncryptedPemFile $privKey "myPassword" "mydomain_enc.pem"]

# We'll need the private key's modulus for the CSR.
# The modulus is not something that needs to be protected.  Most people don't realize
# that a public key is actually just a subset of the private key.  The public parts of
# an RSA private key are the modulus and exponent.  The exponent is always 65537.
set privKeyXml [new_CkXml]

set success [CkXml_LoadXml $privKeyXml [CkPrivateKey_getXml $privKey]]

# Get the modulus in base64 format:
set keyModulus [CkXml_getChildContent $privKeyXml "Modulus"]

# --------------------------------------------------------------------------------
# Now build the CSR using Chilkat's ASN.1 API.
# The keyModulus will be embedded within the ASN.1.

# A new ASN.1 object is automatically a SEQUENCE.
# Given that the CSR's root item is a SEQUENCE, we can use
# this as the root of our CSR.
set asnRoot [new_CkAsn]

# Beneath the root, we have a SEQUENCE (the certificate request info), 
# another SEQUENCE (the algorithm identifier), and a BITSTRING (the signature data)

set success [CkAsn_AppendSequence $asnRoot]
set success [CkAsn_AppendSequence $asnRoot]

# ----------------------------------
# Build the Certificate Request Info
# ----------------------------------
# asnCertReqInfo is a CkAsn
set asnCertReqInfo [CkAsn_GetSubItem $asnRoot 0]
set success [CkAsn_AppendInt $asnCertReqInfo 0]

# Build the Subject part of the Certificate Request Info
# asnCertSubject is a CkAsn
set asnCertSubject [CkAsn_AppendSequenceR $asnCertReqInfo]

# Add each subject part..
# asnTemp is a CkAsn
set asnTemp [CkAsn_AppendSetR $asnCertSubject]
set success [CkAsn_AppendSequence2 $asnTemp]
# AppendSequence2 updates the internal reference to the newly appended SEQUENCE.
# The OID and printable string are added to the SEQUENCE.
set success [CkAsn_AppendOid $asnTemp "2.5.4.6"]
set success [CkAsn_AppendString $asnTemp "printable" "US"]
delete_CkAsn $asnTemp

set asnTemp [CkAsn_AppendSetR $asnCertSubject]
set success [CkAsn_AppendSequence2 $asnTemp]
set success [CkAsn_AppendOid $asnTemp "2.5.4.8"]
set success [CkAsn_AppendString $asnTemp "utf8" "Utah"]
delete_CkAsn $asnTemp

set asnTemp [CkAsn_AppendSetR $asnCertSubject]
set success [CkAsn_AppendSequence2 $asnTemp]
set success [CkAsn_AppendOid $asnTemp "2.5.4.7"]
set success [CkAsn_AppendString $asnTemp "utf8" "Lindon"]
delete_CkAsn $asnTemp

set asnTemp [CkAsn_AppendSetR $asnCertSubject]
set success [CkAsn_AppendSequence2 $asnTemp]
set success [CkAsn_AppendOid $asnTemp "2.5.4.10"]
set success [CkAsn_AppendString $asnTemp "utf8" "DigiCert Inc."]
delete_CkAsn $asnTemp

set asnTemp [CkAsn_AppendSetR $asnCertSubject]
set success [CkAsn_AppendSequence2 $asnTemp]
set success [CkAsn_AppendOid $asnTemp "2.5.4.11"]
set success [CkAsn_AppendString $asnTemp "utf8" "DigiCert"]
delete_CkAsn $asnTemp

set asnTemp [CkAsn_AppendSetR $asnCertSubject]
set success [CkAsn_AppendSequence2 $asnTemp]
set success [CkAsn_AppendOid $asnTemp "2.5.4.3"]
set success [CkAsn_AppendString $asnTemp "utf8" "example.digicert.com"]
delete_CkAsn $asnTemp

delete_CkAsn $asnCertSubject

# Build the Public Key Info part of the Certificate Request Info
# asnPubKeyInfo is a CkAsn
set asnPubKeyInfo [CkAsn_AppendSequenceR $asnCertReqInfo]

# asnPubKeyAlgId is a CkAsn
set asnPubKeyAlgId [CkAsn_AppendSequenceR $asnPubKeyInfo]
set success [CkAsn_AppendOid $asnPubKeyAlgId "1.2.840.113549.1.1.1"]
set success [CkAsn_AppendNull $asnPubKeyAlgId]
delete_CkAsn $asnPubKeyAlgId

# The public key itself is a BIT STRING, but the bit string is composed of ASN.1
# for the RSA public key.  We'll first build the RSA ASN.1 for the public key
# (containing the 2048 bit modulus and exponent), and encoded it to DER, and then add
# the DER bytes as a BIT STRING (as a sub-item of asnPubKeyInfo)

# This is already a SEQUENCE..
set asnRsaKey [new_CkAsn]

# The RSA modulus is a big integer.
set success [CkAsn_AppendBigInt $asnRsaKey $keyModulus "base64"]
set success [CkAsn_AppendInt $asnRsaKey 65537]

set rsaKeyDerBase64 [CkAsn_getEncodedDer $asnRsaKey "base64"]

# Now add the RSA key DER as a BIT STRING.
set success [CkAsn_AppendBits $asnPubKeyInfo $rsaKeyDerBase64 "base64"]
delete_CkAsn $asnPubKeyInfo

# The last part of the certificate request info is an empty context-specific constructed item
# with a tag equal to 0.
set success [CkAsn_AppendContextConstructed $asnCertReqInfo 0]

# Get the DER of the asnCertReqInfo.  
# This will be signed using the RSA private key.
set bdDer [new_CkBinData]

set success [CkAsn_WriteBd $asnCertReqInfo $bdDer]

# Add the signature to the ASN.1
set bdSig [new_CkBinData]

set success [CkRsa_SignBd $rsa $bdDer "SHA1" $bdSig]
set success [CkAsn_AppendBits $asnRoot [CkBinData_getEncoded $bdSig "base64"] "base64"]

delete_CkAsn $asnCertReqInfo

# ----------------------------------
# Finally, add the algorithm identifier, which is the 2nd sub-item under the root.
# ----------------------------------
# asnAlgId is a CkAsn
set asnAlgId [CkAsn_GetSubItem $asnRoot 1]
set success [CkAsn_AppendOid $asnAlgId "1.2.840.113549.1.1.5"]
set success [CkAsn_AppendNull $asnAlgId]
delete_CkAsn $asnAlgId

# Write the CSR to a DER encoded binary file:
set success [CkAsn_WriteBinaryDer $asnRoot "qa_output/mydomain.csr"]
if {$success != 1} then {
    puts [CkAsn_lastErrorText $asnRoot]
    delete_CkRsa $rsa
    delete_CkXml $privKeyXml
    delete_CkAsn $asnRoot
    delete_CkAsn $asnRsaKey
    delete_CkBinData $bdDer
    delete_CkBinData $bdSig
    exit
}

# It is also possible to get the CSR in base64 format:
set csrBase64 [CkAsn_getEncodedDer $asnRoot "base64"]

puts "Base64 CSR:"
puts "$csrBase64"

delete_CkPrivateKey $privKey


delete_CkRsa $rsa
delete_CkXml $privKeyXml
delete_CkAsn $asnRoot
delete_CkAsn $asnRsaKey
delete_CkBinData $bdDer
delete_CkBinData $bdSig