Age | Commit message (Collapse) | Author |
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Adding symbols to an ELF file doesn't solve the problem we're trying
to solve. We want to be able to identify which application is running
on a board when we don't know what ELF file has been loaded in flash.
A checksum over the contens of the flash memory seems less dumb.
This reverts commit 49d39287252bf0bd2b3fd75e86d07616b56c7fd2.
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Using different baud rates for the two otherwise compatible
applications risk confusing users of both applications. An espeicially
unlucky case is setting host side to 460800 while reading from a
board set to 921600 -- the stream will look random while it's actually
pretty bad.
Raising 'entropy' rather than lowering 'cc20rng' is motivated by the
fact that cc20rng saturates 460800 baud(*) with its ~75 kB/s output.
(*) 460800 baud should be 57.6 kB/s or 51.2 kB/s, depending on whether
or not the stop bit is counted towards the baud rate. I would suppose
it is.
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- chacha20_prng_block() uses counter in the state struct
- chacha20_setup() replaces chacha20_prng_reseed() and fills the whole
state struct, fixing a bug where only half of the key was being set;
as a result of 'counter' being set, a state struct filled with
entropy from the TRNG makes reseeding occur after a random number of
rounds instead of after a fixed 2^32-1 rounds
- decrementing of the block counter is done in chacha20_prng_block()
- chacha output is copied to buf _after_ the interrupt driven
transmission of buf to UART has finished, to stop the race between
reading and refilling of buf
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Keep indentation level 2 in main.c to minimise changes.
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That's too destructive (and also it doesn't work well with .~/).
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In other words, enable the USART connected to the serial port on
the Raspberry Pi GPIO header.
Sending a newline to either USART directs the generated entropy
to that USART.
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