during ./configure I get the following result: [...] checking whether we can use curve25519-donna-c64... no checking whether we can use curve25519 from nacl... no I do have nacl(-devel) installed on my machine. Closer inspection of config.log tells me that conftest.c has "#include <crypto_scalarmult_curve25519.h>". That file is in /usr/include/nacl, so I had to add "-I/usr/include/nacl" for this particular error to pass. That didn't work though as I am now getting "conftest.c:58:4: error: #error Hey, this is the reference implementation!". The conftest.c file itself has this: #include <crypto_scalarmult_curve25519.h> #ifdef crypto_scalarmult_curve25519_ref_BYTES #error Hey, this is the reference implementation! #endif "crypto_scalarmult_curve25519_ref_BYTES" is indeed defined in /usr/include/nacl/crypto_scalarmult_curve25519.h, so how am I supposed to satisfy this test then? **Trac**: **Username**: mr-4