Step 2: Extract Certificate Bundle as Message
Use the extracted signing certificate (RootBundleSigningCertificate.cer) to verify the Trusted Union Root bundle (ios_union.p7b).
# This command extracts the certificate bundle as a message into the
# file iosBundleBodyVerified.p7b if the signature verifies
openssl cms -verify -nointern -noverify -inform DER -in ios_union.p7b -outform DER \
-out iosBundleBodyVerified.p7b -certfile RootBundleSigningCertificate.cer
The output is similar to:
Verification successful