Verify webhook request HMACs

1 files changed, 29 insertions, 0 deletions

diff --git a/mod/hmac.hxx b/mod/hmac.hxx
new file mode 100644
index 0000000..586d0e8
--- /dev/null
+++ b/mod/hmac.hxx
@@ -0,0 +1,29 @@
+#ifndef MOD_HMAC_HXX
+#define MOD_HMAC_HXX
+
+#include <libbrep/types.hxx>
+#include <libbrep/utility.hxx>
+
+#include <mod/module-options.hxx>
+
+namespace brep
+{
+  // Compute the HMAC-SHA256 message authentication code over a message using
+  // the given key (alpha-numeric string, not encoded).
+  //
+  // Return the HMAC value or throw std::system_error in case of an error.
+  //
+  // Example output:
+  //
+  //   5e822587094c68e646db8b916da1db2056d92f1dea4252136a533b4147a30cb7
+  //
+  // Note that although any cryptographic hash function can be used to compute
+  // an HMAC, this implementation supports only SHA-256.
+  //
+  string
+  compute_hmac (const options::openssl_options&,
+                const void* message, size_t len,
+                const char* key);
+}
+
+#endif