  We make a new proposal about how to use in an effective way a CSPRBG
(Computationally Secure Pseudo Random Bit Generator) for cryptographic
purposes. We introduce the definitions of TCSPRBG (Typical CSPRBG) and SCSPRBG
(Special CSPRBG). In particular the definition of SCSPRBG synthetizes in a
simple way our proposal of how to modify a CSPRBG in order to achieve a higher
throughput rate, while retaining some essential features of its computational
security.
  We then summarize which should be, in our opinion, a "standard way" to use a
CSPRBG for cryptographic purposes. We eventually present as an application, a
particular SCSPRBG for which we can achieve throughput rates greater than $100$
Mbits/sec on current mobile devices.
