The one-step "signtool sign /fd sha256" fails on the build host with
0xc0000225 before the PIN is asked for, because crypt32 converts the
legacy CryptoAPI key handle to a CNG one for SHA-2 digests, and no CNG
provider is registered under the name of Certum's crypto3 CSP. Rebinding
to cryptoCertum3 KSP is not an option, as it cannot see the Common
profile's code-signing key.
signtool's split flow avoids the conversion, so pkg/win32/sign-files.bat
now does the signing in /dg, /ds, /di, timestamp and verify steps, with
one PIN prompt per call as before. Make.bat's :SIGN_FILES and Inno
Setup's SignTool both go through it, the latter via cmd /c.
Also default PGADMIN_SIGNTOOL_DIR to SDK 10.0.26100.0, the one installed
on the host, and match the PIN dialog on "Logowanie do profilu zwyk" so
that a Secure profile prompt is never answered with the Common PIN.
SIGNING.md gains the full setup procedure, the root cause and the split
signing flow.