2 files changed, 4 insertions, 1 deletions
diff --git a/README.rst b/README.rst
index 133be3e..ebe612e 100644
--- a/README.rst
+++ b/README.rst
@@ -28,7 +28,7 @@ Install
 .. code-block:: bash
 
     git clone https://github.com/Determinant/ethy.py
-    pip install --user ethy.py/
+    pip3 install --user ethy.py/
 
 Example
 -------
diff --git a/ethy.py b/ethy.py
index cf5e932..a480d1e 100644
--- a/ethy.py
+++ b/ethy.py
@@ -117,6 +117,9 @@ def encrypt(passwd=None, salt=None, n=None, r=None, p=None, dklen=None, iv=None,
 def show_entropy(bytes, prompt="pass"):
     pwd_len = len(bytes)
     pwd_ent = entropy(bytes)
+    if pwd_len < 2:
+        err.write("{} is too short!\n".format(prompt))
+        sys.exit(1)
     err.write("{0} length = {1} bytes\n"
             "{0} entropy = {2}, {3:.2f}%\n".format(prompt,
                 pwd_len, pwd_ent, pwd_ent / log(pwd_len, 2) * 100))