2 files changed, 8 insertions, 0 deletions
diff --git a/src/common/util.c b/src/common/util.c
index d05c308fe8..139c1aaad8 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -684,6 +684,13 @@ tor_digest_is_zero(const char *digest)
   return tor_mem_is_zero(digest, DIGEST_LEN);
 }
 
+/** Return true iff the DIGEST256_LEN bytes in digest are all zero. */
+int
+tor_digest256_is_zero(const char *digest)
+{
+  return tor_mem_is_zero(digest, DIGEST256_LEN);
+}
+
 /* Helper: common code to check whether the result of a strtol or strtoul or
  * strtoll is correct. */
 #define CHECK_STRTOX_RESULT()                           \
diff --git a/src/common/util.h b/src/common/util.h
index 28ea8a0488..85234f5157 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -195,6 +195,7 @@ const char *find_whitespace(const char *s) ATTR_PURE;
 const char *find_whitespace_eos(const char *s, const char *eos) ATTR_PURE;
 int tor_mem_is_zero(const char *mem, size_t len) ATTR_PURE;
 int tor_digest_is_zero(const char *digest) ATTR_PURE;
+int tor_digest256_is_zero(const char *digest) ATTR_PURE;
 char *esc_for_log(const char *string) ATTR_MALLOC;
 const char *escaped(const char *string);
 struct smartlist_t;