Generate Self-signed certificate with Root CA Signer
The ultimate solution in my case, avoiding makecert and openssl was to use Powershell and BouncyCastle. I forked the PSBouncyCastle repo from PSBouncyCastle by RLipscombe and pushed 1.8.1 Bouncy Castle in. My forked version is the one I've used for the script, the fork resides at Forked: PSBouncyCastle.New.
I then used StackOverflow: C# Generate Certificates on the Fly as inspiration to write the following powershell below, I will be adding this to my GitHub and commenting, and I will amend this as soon as I do:
Import-Module -Name PSBouncyCastle.Newfunction New-SelfSignedCertificate { [CmdletBinding()] param ( [string]$SubjectName, [string]$FriendlyName = "New Certificate", [object]$Issuer, [bool]$IsCA = $false, [int]$KeyStrength = 2048, [int]$ValidYears = 2, [hashtable]$EKU = @{} ) # Needed generators $random = New-SecureRandom $certificateGenerator = New-CertificateGenerator if($Issuer -ne $null -and $Issuer.HasPrivateKey -eq $true) { $IssuerName = $Issuer.IssuerName.Name $IssuerPrivateKey = $Issuer.PrivateKey } # Create and set a random certificate serial number $serial = New-SerialNumber -Random $random $certificateGenerator.SetSerialNumber($serial) # The signature algorithm $certificateGenerator.SetSignatureAlgorithm('SHA256WithRSA') # Basic Constraints - certificate is allowed to be used as intermediate. # Powershell requires either a $null or reassignment or it will return this from the function $certificateGenerator = Add-BasicConstraints -isCertificateAuthority $IsCA -certificateGenerator $certificateGenerator # Key Usage if($EKU.Count -gt 0) { $certificateGenerator = $certificateGenerator | Add-ExtendedKeyUsage @EKU } # Create and set the Issuer and Subject name $subjectDN = New-X509Name -Name ($SubjectName) if($Issuer -ne $null) { $IssuerDN = New-X509Name -Name ($IssuerName) } else { $IssuerDN = New-X509Name -Name ($SubjectName) } $certificateGenerator.SetSubjectDN($subjectDN) $certificateGenerator.SetIssuerDN($IssuerDN) # Authority Key and Subject Identifier if($Issuer -ne $null) { $IssuerKeyPair = ConvertTo-BouncyCastleKeyPair -PrivateKey $IssuerPrivateKey $IssuerSerial = [Org.BouncyCastle.Math.BigInteger]$Issuer.GetSerialNumber() $authorityKeyIdentifier = New-AuthorityKeyIdentifier -name $Issuer.IssuerName.Name -publicKey $IssuerKeyPair.Public -serialNumber $IssuerSerial $certificateGenerator = Add-AuthorityKeyIdentifier -certificateGenerator $certificateGenerator -authorityKeyIdentifier $authorityKeyIdentifier } # Validity range of the certificate [DateTime]$notBefore = (Get-Date).AddDays(-1) if($ValidYears -gt 0) { [DateTime]$notAfter = $notBefore.AddYears($ValidYears) } $certificateGenerator.SetNotBefore($notBefore) $certificateGenerator.SetNotAfter($notAfter) # Subject public key ~and private $subjectKeyPair = New-KeyPair -Strength $keyStrength -Random $random if($IssuerPrivateKey -ne $null) { $IssuerKeyPair = [Org.BouncyCastle.Security.DotNetUtilities]::GetKeyPair($IssuerPrivateKey) } else { $IssuerKeyPair = $subjectKeyPair } $certificateGenerator.SetPublicKey($subjectKeyPair.Public) # Create the Certificate $IssuerKeyPair = $subjectKeyPair $certificate = $certificateGenerator.Generate($IssuerKeyPair.Private, $random) # At this point you have the certificate and need to convert it and export, I return the private key for signing the next cert $pfxCertificate = ConvertFrom-BouncyCastleCertificate -certificate $certificate -subjectKeyPair $subjectKeyPair -friendlyName $FriendlyName return $pfxCertificate}
A few examples of usage for this powershell would be:
Generate a Root CA
$TestRootCA = New-SelfSignedCertificate -subjectName "CN=TestRootCA" -IsCA $trueExport-Certificate -Certificate $test -OutputFile "TestRootCA.pfx" -X509ContentType Pfx
Generate a Standard Self Signed
$TestSS = New-SelfSignedCertificate -subjectName "CN=TestLocal"Export-Certificate -Certificate $TestSS -OutputFile "TestLocal.pfx" -X509ContentType Pfx
Generate a certificate, signing with a root certificate
$TestRootCA = New-SelfSignedCertificate -subjectName "CN=TestRootCA" -IsCA $true$TestSigned = New-SelfSignedCertificate -subjectName "CN=TestSignedByRoot" -issuer $TestRootCAExport-Certificate -Certificate $test -OutputFile "TestRootCA.pfx" -X509ContentType PfxExport-Certificate -Certificate $test -OutputFile "TestRootCA.pfx" -X509ContentType Pfx
Generate a Self-Signed with Specific Usage
$TestServerCert = New-SelfSignedCertificate -subjectName "CN=TestServerCert" -EKU @{ "ServerAuthentication" = $true }
Note that the -EKU parameter accepts via splatting, it does this to ensure that anything added to Add-ExtendedKeyUsage is validly passed. It accepts the following certificate usages:
- DigitalSignature
- NonRepudiation
- KeyEncipherment
- DataEncipherment
- KeyAgreement
- KeyCertSign
- CrlSign
- EncipherOnly
- DecipherOnly
This fits my need and seems to work across all Windows Platforms we are using for dynamic environments.
How about simply doing this:
$cert = New-SelfSignedCertificate -FriendlyName "MyCA" -KeyExportPolicy ExportableEncrypted -Provider "Microsoft Strong Cryptographic Provider" -Subject "SN=TestRootCA" -NotAfter (Get-Date).AddYears($ExpiryInYears) -CertStoreLocation Cert:\LocalMachine\My -KeyUsageProperty All -KeyUsage CertSign, CRLSign, DigitalSignature
Important parameters are -KeyUsageProperty
and -KeyUsage
.
"Itiverba Self-Signed certificate generator" (http://www.itiverba.com/en/software/itisscg.php) is a free GUI tool for Windows that allows you to create your own CA certificates and sign end-certificates with it. You can export the certificates in PEM, CER, DER, PFX file formats.
It's just 3 lines to encode :
Subject: CN="Testcorp - Private CA"
Basic Constraints: V (checked)
Basic Constraints / Subject Type: CA
Give a file name and select a file format, then click on the "create certificate" button. Your Custom CA certificate is done.