Create CA file
$c = New-SelfSignedCertificate -DnsName SelfSignedCA -CertStoreLocation Cert:\CurrentUser\My -NotAfter (Get-Date).AddYears(10)
check certificate fingerprint
$c
PSParentPath: Microsoft.PowerShell.Security\Certificate::CurrentUser\My
Thumbprint Subject
---------- -------
07AA8E037F6D1D83CA1B5023318981DDFB546BFB CN=SelfSignedCA
Sign Certificate for code signing
New-SelfSignedCertificate -Type CodeSigningCert -Subject "May Meow" -CertStoreLocation "Cert:\CurrentUser\My" -KeySpec 2 -Signer $c
# or later
# use full path to your certificate
New-SelfSignedCertificate -Type CodeSigningCert -Subject "May Meow" -CertStoreLocation "Cert:\CurrentUser\My" -KeySpec 2 -Signer Cert:\CurrentUser\My\07AA8E037F6D1D83CA1B5023318981DDFB546BFB -HashAlgorithm "sha1"