Okay here I've tried a similar solution to the go-pointers library... but i had to change it a bit to fit how the C library uses the context pointer: https://git.xx.network/elixxir/ctidh_cgo/-/commit/8f02611b943c269eab5b6e888958e4d41d72cd51
It builds and runs... and then panics on the "rng is nil"... not sure why. So I'm going to try another solution where I change the C api slightly. I'm convinced there are many possible solutions to this and picking one is a matter of deciding among a few tradeoffs. On Tuesday, October 18, 2022 at 6:33:11 PM UTC-4 David Stainton wrote: > Greetings cgo experts, perhaps this post might also be of some interest to > cryptography people as well. > > What's the best way for a C cryptography library to receive entropy from > golang? > > There exists a C cryptography library (CTIDH, it's a PQ NIKE)... I am > collaborating with C programmers who are adding features to it. I maintain > cgo bindings for this library. Thus far the cgo is straight forward and it > works. However the C programmers recently added a constructor for private > keys which takes a function pointer as an argument: > > https://codeberg.org/io/highctidh/src/branch/main/csidh.h#L50 > > /* > * generate a new private key using rng_callback and write the result to > (priv). > * (priv) is passed as (context) to the rng_callback. > */ > void csidh_private_withrng(private_key *priv, ctidh_fillrandom > rng_callback); > > I did get this to work with an ugly hack where the golang constructor > takes an io.Reader interface object as an argument and sets an unexported > module scoped global variable to the rng/io.Reader object, guarded by a > mutex, gross: > > > https://git.xx.network/elixxir/ctidh_cgo/-/commit/2e7fb078722decb07ab8da7fb59c8ec46fb32fd1 > > But that's a really ugly hack and if called by multiple threads would > result in the rng getting overwritten... which in most cases is probably > fine for that to happen but seems like a bad design. > > > > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/cfcb3675-eb9a-46b6-85a8-ceaa1329c185n%40googlegroups.com.
