diff --git a/src/pow.h b/src/pow.h
--- a/src/pow.h
+++ b/src/pow.h
@@ -8,6 +8,7 @@
 
 #include <cstdint>
 
+struct BlockHash;
 class CBlockHeader;
 class CBlockIndex;
 class uint256;
@@ -27,7 +28,7 @@
  * Check whether a block hash satisfies the proof-of-work requirement specified
  * by nBits
  */
-bool CheckProofOfWork(uint256 hash, uint32_t nBits,
+bool CheckProofOfWork(const BlockHash &hash, uint32_t nBits,
                       const Consensus::Params &params);
 
 /**
diff --git a/src/pow.cpp b/src/pow.cpp
--- a/src/pow.cpp
+++ b/src/pow.cpp
@@ -11,6 +11,7 @@
 #include <consensus/activation.h>
 #include <consensus/params.h>
 #include <primitives/block.h>
+#include <primitives/blockhash.h>
 #include <uint256.h>
 #include <util/system.h>
 
@@ -139,7 +140,7 @@
     return bnNew.GetCompact();
 }
 
-bool CheckProofOfWork(uint256 hash, uint32_t nBits,
+bool CheckProofOfWork(const BlockHash &hash, uint32_t nBits,
                       const Consensus::Params &params) {
     bool fNegative;
     bool fOverflow;