diff --git a/contracts/HashedTimelock.sol b/contracts/HashedTimelock.sol
index 97ad747..eb13142 100644
--- a/contracts/HashedTimelock.sol
+++ b/contracts/HashedTimelock.sol
@@ -211,7 +211,7 @@ contract HashedTimelock {
      * @return the hashed secret.
      */
      function hashSecret(bytes32 secret)
-         constant
+         pure
          public
          returns(bytes32 hashed)
      {
diff --git a/contracts/HashedTimelockERC20.sol b/contracts/HashedTimelockERC20.sol
index ad16228..0f7e8c4 100644
--- a/contracts/HashedTimelockERC20.sol
+++ b/contracts/HashedTimelockERC20.sol
@@ -250,7 +250,7 @@ contract HashedTimelockERC20 {
      * @return the hashed secret.
      */
     function hashSecret(bytes32 secret)
-        constant
+        pure
         public
         returns(bytes32 hashed)
     {