class OpenSSL::Timestamp::Factory

Used to generate a Response from scratch.

Please bear in mind that the implementation will always apply and prefer the policy object identifier given in the request over the default policy id specified in the Factory. As a consequence, default_policy_id will only be applied if no Request#policy_id was given. But this also means that one needs to check the policy identifier in the request manually before creating the Response, e.g. to check whether it complies to a specific set of acceptable policies.

There exists also the possibility to add certificates (instances of OpenSSL::X509::Certificate) besides the timestamping certificate that will be included in the resulting timestamp token if Request#cert_requested? is true. Ideally, one would also include any intermediate certificates (the root certificate can be left out - in order to trust it any verifying party will have to be in its possession anyway). This simplifies validation of the timestamp since these intermediate certificates are “already there” and need not be passed as external parameters to Response#verify anymore, thus minimizing external resources needed for verification.

Example: Inclusion of (untrusted) intermediate certificates

Assume we received a timestamp request that has set Request#policy_id to nil and Request#cert_requested? to true. The raw request bytes are stored in a variable called req_raw. We’d still like to integrate the necessary intermediate certificates (in inter1.cer and inter2.cer) to simplify validation of the resulting Response. ts.p12 is a PKCS#12-compatible file including the private key and the timestamping certificate.

req = OpenSSL::Timestamp::Request.new(raw_bytes)
p12 = OpenSSL::PKCS12.new(File.binread('ts.p12'), 'pwd')
inter1 = OpenSSL::X509::Certificate.new(File.binread('inter1.cer'))
inter2 = OpenSSL::X509::Certificate.new(File.binread('inter2.cer'))
fac = OpenSSL::Timestamp::Factory.new
fac.gen_time = Time.now
fac.serial_number = 1
fac.allowed_digests = ["sha256", "sha384", "sha512"]
#needed because the Request contained no policy identifier
fac.default_policy_id = '1.2.3.4.5'
fac.additional_certificates = [ inter1, inter2 ]
timestamp = fac.create_timestamp(p12.key, p12.certificate, req)