diff --git a/ipmi.hpp b/ipmi.hpp
index 050f7ca..e80c68e 100644
--- a/ipmi.hpp
+++ b/ipmi.hpp
@@ -51,3 +51,16 @@
  */
 ipmi_ret_t dataFinish(UpdateInterface* updater, const uint8_t* reqBuf,
                       uint8_t* replyBuf, size_t* dataLen);
+
+/**
+ * Prepare to receive a BMC image signature.
+ *
+ * @param[in] updater - Pointer to Updater object.
+ * @param[in] reqBuf - the IPMI packet.
+ * @param[in] replyBuf - Pointer to buffer for any response.
+ * @param[in,out] dataLen - Initially reqBuf length, set to replyBuf
+ * length when done.
+ * @return corresponding IPMI return code.
+ */
+ipmi_ret_t startHash(UpdateInterface* updater, const uint8_t* reqBuf,
+                     uint8_t* replyBuf, size_t* dataLen);