1 files changed, 17 insertions, 0 deletions

diff --git a/nacl/crypto_box/curve25519xsalsa20poly1305/ref/before.c b/nacl/crypto_box/curve25519xsalsa20poly1305/ref/before.c
new file mode 100644
index 00000000..279bb12a
--- /dev/null
+++ b/nacl/crypto_box/curve25519xsalsa20poly1305/ref/before.c
@@ -0,0 +1,17 @@
+#include "crypto_core_hsalsa20.h"
+#include "crypto_scalarmult_curve25519.h"
+#include "crypto_box.h"
+
+static const unsigned char sigma[16] = "expand 32-byte k";
+static const unsigned char n[16] = {0};
+
+int crypto_box_beforenm(
+  unsigned char *k,
+  const unsigned char *pk,
+  const unsigned char *sk
+)
+{
+  unsigned char s[32];
+  crypto_scalarmult_curve25519(s,sk,pk);
+  return crypto_core_hsalsa20(k,n,s,sigma);
+}