diff --git a/git_explode/exploder.py b/git_explode/exploder.py
index 19452a7..ee96f88 100644
--- a/git_explode/exploder.py
+++ b/git_explode/exploder.py
@@ -97,7 +97,7 @@ def explode(self, commits, deps_from, deps_on):
 
         while todo:
             commit = todo.pop(0)
-            sha = commit.hex
+            sha = str(commit.id)
             self.logger.debug("Exploding %s" % GitUtils.commit_summary(commit))
             if unexploded_deps_from[sha]:
                 abort("BUG: unexploded deps from %s" %
@@ -151,7 +151,7 @@ def queue_new_leaves(self, todo, exploded_commit, commits, deps_on,
         added to the explode queue.
 
         """
-        sha1 = exploded_commit.hex
+        sha1 = str(exploded_commit.id)
         for dependent in deps_on[sha1]:
             del unexploded_deps_from[dependent][sha1]
             if not unexploded_deps_from[dependent]:
diff --git a/git_explode/listener.py b/git_explode/listener.py
index 079e177..df8dc8c 100644
--- a/git_explode/listener.py
+++ b/git_explode/listener.py
@@ -18,14 +18,14 @@ def __init__(self, options):
     def new_commit(self, commit):
         """Adds the commit if it doesn't already exist.
         """
-        sha1 = commit.hex
+        sha1 = str(commit.id)
         for d in (self._dependencies_from, self._dependencies_on):
             if sha1 not in d:
                 d[sha1] = {}
 
     def new_dependency(self, dependee, dependency, path, line_num):
-        src = dependee.hex
-        dst = dependency.hex
+        src = str(dependee.id)
+        dst = str(dependency.id)
 
         cause = "%s:%d" % (path, line_num)
         self._dependencies_from[src][dst] = cause