diff --git a/Crypto/Random/AESCtr.hs b/Crypto/Random/AESCtr.hs
--- a/Crypto/Random/AESCtr.hs
+++ b/Crypto/Random/AESCtr.hs
@@ -24,7 +24,7 @@
 
 import Crypto.Random
 import System.Random (RandomGen(..))
-import System.Crypto.Random (getEntropy)
+import System.Entropy (getEntropy)
 import qualified Crypto.Cipher.AES as AES
 
 import Data.ByteString (ByteString)
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -13,3 +13,25 @@
     let (ran, rng') = getRandomBytes rng 1024
 
 it's also an instance of CryptoRandomGen from the crypto-api package.
+
+Statistics
+----------
+
+Using ent, a randomness property maker on one 1Mb sample.
+
+cprng-AES:
+
+    Entropy = 7.999837 bits per byte.
+    Optimum compression would reduce the size of this 1048576 byte file by 0 percent.
+    Chi square distribution for 1048576 samples is 237.02.
+    Arithmetic mean value of data bytes is 127.3422 (127.5 = random).
+    Monte Carlo value for Pi is 3.143589568 (error 0.06 percent).
+
+Compared to urandom with the same sampling:
+
+    Entropy = 7.999831 bits per byte.
+    Optimum compression would reduce the size of this 1048576 byte file by 0 percent.
+    Chi square distribution for 1048576 samples is 246.63.
+    Arithmetic mean value of data bytes is 127.6347 (127.5 = random).
+    Monte Carlo value for Pi is 3.132465868 (error 0.29 percent).
+
diff --git a/cprng-aes.cabal b/cprng-aes.cabal
--- a/cprng-aes.cabal
+++ b/cprng-aes.cabal
@@ -1,5 +1,5 @@
 Name:                cprng-aes
-Version:             0.2.1
+Version:             0.2.2
 Description:         
     Simple crypto pseudo-random-number-generator with really good randomness property.
     .
@@ -34,7 +34,8 @@
   Build-Depends:     base >= 3 && < 5
                    , bytestring
                    , random
-                   , crypto-api >= 0.5
+                   , crypto-api >= 0.8
+                   , entropy >= 0.2
                    , cryptocipher >= 0.2.5 && < 0.3.0
                    , cereal >= 0.3.0 && < 0.4.0
   Exposed-modules:   Crypto.Random.AESCtr