Gem::Security::Policy#check_key

# File tmp/rubies/ruby-3.0.5/lib/rubygems/security/policy.rb, line 111
def check_key(signer, key)
  unless signer and key
    return true unless @only_signed

    raise Gem::Security::Exception, 'missing key or signature'
  end

  public_key = Gem::Security.get_public_key(key)

  raise Gem::Security::Exception,
    "certificate #{signer.subject} does not match the signing key" unless
      signer.public_key.to_pem == public_key.to_pem

  true
end