Gem::Commands::CertCommand#open_private_key

# File tmp/rubies/ruby-3.2.0/lib/rubygems/commands/cert_command.rb, line 94
def open_private_key(key_file)
  check_openssl
  passphrase = ENV["GEM_PRIVATE_KEY_PASSPHRASE"]
  key = OpenSSL::PKey.read File.read(key_file), passphrase
  raise Gem::OptionParser::InvalidArgument,
    "#{key_file}: private key not found" unless key.private?
  key
rescue Errno::ENOENT
  raise Gem::OptionParser::InvalidArgument, "#{key_file}: does not exist"
rescue OpenSSL::PKey::PKeyError, ArgumentError
  raise Gem::OptionParser::InvalidArgument, "#{key_file}: invalid RSA, DSA, or EC key"
end