diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index a512ff870..51a6d8f5e 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import errno
 import getopt
 import getpass
 import os
@@ -132,13 +133,14 @@ def GetKeyPasswords(keylist):
   those which require them.  Return a {key: password} dict.  password
   will be None if the key has no password."""
 
-  key_passwords = {}
+  no_passwords = []
+  need_passwords = []
   devnull = open("/dev/null", "w+b")
   for k in sorted(keylist):
     # An empty-string key is used to mean don't re-sign this package.
     # Obviously we don't need a password for this non-key.
     if not k:
-      key_passwords[k] = None
+      no_passwords.append(k)
       continue
 
     p = subprocess.Popen(["openssl", "pkcs8", "-in", k+".pk8",
@@ -148,12 +150,13 @@ def GetKeyPasswords(keylist):
                          stderr=subprocess.STDOUT)
     p.communicate()
     if p.returncode == 0:
-      print "%s.pk8 does not require a password" % (k,)
-      key_passwords[k] = None
+      no_passwords.append(k)
     else:
-      key_passwords[k] = getpass.getpass("Enter password for %s.pk8> " % (k,))
+      need_passwords.append(k)
   devnull.close()
-  print
+
+  key_passwords = PasswordManager().GetPasswords(need_passwords)
+  key_passwords.update(dict.fromkeys(no_passwords, None))
   return key_passwords
 
 
@@ -278,3 +281,102 @@ def Cleanup():
       shutil.rmtree(i)
     else:
       os.remove(i)
+
+
+class PasswordManager(object):
+  def __init__(self):
+    self.editor = os.getenv("EDITOR", None)
+    self.pwfile = os.getenv("ANDROID_PW_FILE", None)
+
+  def GetPasswords(self, items):
+    """Get passwords corresponding to each string in 'items',
+    returning a dict.  (The dict may have keys in addition to the
+    values in 'items'.)
+
+    Uses the passwords in $ANDROID_PW_FILE if available, letting the
+    user edit that file to add more needed passwords.  If no editor is
+    available, or $ANDROID_PW_FILE isn't define, prompts the user
+    interactively in the ordinary way.
+    """
+
+    current = self.ReadFile()
+
+    first = True
+    while True:
+      missing = []
+      for i in items:
+        if i not in current or not current[i]:
+          missing.append(i)
+      # Are all the passwords already in the file?
+      if not missing: return current
+
+      for i in missing:
+        current[i] = ""
+
+      if not first:
+        print "key file %s still missing some passwords." % (self.pwfile,)
+        answer = raw_input("try to edit again? [y]> ").strip()
+        if answer and answer[0] not in 'yY':
+          raise RuntimeError("key passwords unavailable")
+      first = False
+
+      current = self.UpdateAndReadFile(current)
+
+  def PromptResult(self, current):
+    """Prompt the user to enter a value (password) for each key in
+    'current' whose value is fales.  Returns a new dict with all the
+    values.
+    """
+    result = {}
+    for k, v in sorted(current.iteritems()):
+      if v:
+        result[k] = v
+      else:
+        while True:
+          result[k] = getpass.getpass("Enter password for %s key> "
+                                      % (k,)).strip()
+          if result[k]: break
+    return result
+
+  def UpdateAndReadFile(self, current):
+    if not self.editor or not self.pwfile:
+      return self.PromptResult(current)
+
+    f = open(self.pwfile, "w")
+    os.chmod(self.pwfile, 0600)
+    f.write("# Enter key passwords between the [[[ ]]] brackets.\n")
+    f.write("# (Additional spaces are harmless.)\n\n")
+
+    first_line = None
+    sorted = [(not v, k, v) for (k, v) in current.iteritems()]
+    sorted.sort()
+    for i, (_, k, v) in enumerate(sorted):
+      f.write("[[[  %s  ]]] %s\n" % (v, k))
+      if not v and first_line is None:
+        # position cursor on first line with no password.
+        first_line = i + 4
+    f.close()
+
+    p = Run([self.editor, "+%d" % (first_line,), self.pwfile])
+    _, _ = p.communicate()
+
+    return self.ReadFile()
+
+  def ReadFile(self):
+    result = {}
+    if self.pwfile is None: return result
+    try:
+      f = open(self.pwfile, "r")
+      for line in f:
+        line = line.strip()
+        if not line or line[0] == '#': continue
+        m = re.match(r"^\[\[\[\s*(.*?)\s*\]\]\]\s*(\S+)$", line)
+        if not m:
+          print "failed to parse password file: ", line
+        else:
+          result[m.group(2)] = m.group(1)
+      f.close()
+    except IOError, e:
+      if e.errno != errno.ENOENT:
+        print "error reading password file: ", str(e)
+    return result
diff --git a/tools/releasetools/sign_target_files_apks b/tools/releasetools/sign_target_files_apks
index 844182d68..9f393c80d 100755
--- a/tools/releasetools/sign_target_files_apks
+++ b/tools/releasetools/sign_target_files_apks
@@ -141,7 +141,7 @@ def CheckSharedUserIdsConsistent(input_tf_zip, apk_key_map):
   going to be signed with the same key."""
 
   shared_user_apks = {}
-  maxlen = 0
+  maxlen = len("(unknown key)")
 
   for info in input_tf_zip.infolist():
     if info.filename.endswith(".apk"):
@@ -172,7 +172,7 @@ def CheckSharedUserIdsConsistent(input_tf_zip, apk_key_map):
   for user, keys in errors:
     print 'shared user id "%s":' % (user,)
     for key, apps in keys.iteritems():
-      print '  %-*s   %s' % (maxlen, key, apps[0])
+      print '  %-*s   %s' % (maxlen, key or "(unknown key)", apps[0])
       for a in apps[1:]:
         print (' ' * (maxlen+5)) + a
     print