3-Heights™ PDF Security Shell - PDF Tools AG

3-Heights PDF Security Shell, Version 4.2 Page 24 of 35
July 8, 2013
5.7 Caching of CRLs, OCSP and TSP Reponses
In order to improve the speed when mass signing, the 3-Heights PDF Security Shell provides a caching
algorithm to store CRL (Certificate Revocation List), OCSP (Online Certificate Status Protocol) and TSP
(Time Stamp Protocol). This data is usually valid over period of time that is defined by the provider, which
is normally at least 24 hours. Caching improves the speed, because there are situations when the server
of the provider does not need to be contacted for every digital signature. The following caches are stored
automatically by the 3-Heights PDF Security Shell at the indicated location:
OCSP responses: /temp/ocsp/server-serial.der
CRL:
TSP responses 1 :
/temp/crl/server.der
/temp/tsp/server.der
The caches can be cleared by deleting the files. However, if a file is present it must be valid (i.e. stored by
the caching mechanism).
The files are updated if the current date and time exceeds the “next update” field in the OCSP response or
CRL respectively.
1 TSP responses are not embedded but only used for the computation of the signature length.
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