Allow the use of the iPXE DRBG implementation in BSD-licensed
projects.
Requested-by: Sean Davis <dive@hq.endersgame.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ANS X9.82 specifies several Approved Sources of Entropy Input (SEI).
One such SEI uses an entropy source as the Source of Entropy Input,
condensing each entropy source output after each GetEntropy call.
This can be implemented relatively cheaply in iPXE and avoids the need
to allocate potentially very large buffers.
(Note that the terms "entropy source" and "Source of Entropy Input"
are not synonyms within the context of ANS X9.82.)
Use the iPXE API mechanism to allow entropy sources to be selected at
compilation time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Treat an empty (zeroed) DRBG as invalid. This ensures that a DRBG
that has not yet been instantiated (or that has been uninstantiated)
will refuse to attempt to generate random bits.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ANS X9.82 specifies that an Approved DRBG must consist of an Approved
algorithm wrapped inside an envelope which handles entropy gathering,
prediction resistance, automatic reseeding and other housekeeping
tasks.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown