diff --git a/ethash.go b/ethash.go
index 837a16c1..4831b60e 100644
--- a/ethash.go
+++ b/ethash.go
@@ -103,8 +103,8 @@ func freeCache(cache *cache) {
 	cache.ptr = nil
 }
 
-func (cache *cache) compute(dagSize uint64, hash common.Hash, nonce uint64) (ok bool, mixDigest, result common.Hash) {
-	ret := C.ethash_light_compute_internal(cache.ptr, C.uint64_t(dagSize), hashToH256(hash), C.uint64_t(nonce))
+func (cache *cache) compute(dagSize uint64, hash common.Hash, nonce uint64, block_number uint64) (ok bool, mixDigest, result common.Hash) {
+	ret := C.progpow_light_compute_internal(cache.ptr, C.uint64_t(dagSize), hashToH256(hash), C.uint64_t(nonce), C.uint64_t(block_number))
 	// Make sure cache is live until after the C call.
 	// This is important because a GC might happen and execute
 	// the finalizer before the call completes.
@@ -151,7 +151,7 @@ func (l *Light) Verify(block Block) bool {
 		dagSize = dagSizeForTesting
 	}
 	// Recompute the hash using the cache.
-	ok, mixDigest, result := cache.compute(uint64(dagSize), block.HashNoNonce(), block.Nonce())
+	ok, mixDigest, result := cache.compute(uint64(dagSize), block.HashNoNonce(), block.Nonce(), blockNum)
 	if !ok {
 		return false
 	}
diff --git a/ethashc.go b/ethashc.go
index 1d2ba161..63b51f41 100644
--- a/ethashc.go
+++ b/ethashc.go
@@ -33,6 +33,7 @@ package ethash
 #cgo LDFLAGS: -lm
 
 #include "src/libethash/internal.c"
+#include "src/libethash/progpow-internal.c"
 #include "src/libethash/sha3.c"
 #include "src/libethash/io.c"
 
diff --git a/src/libethash/ethash.h b/src/libethash/ethash.h
index d050b426..04e87395 100644
--- a/src/libethash/ethash.h
+++ b/src/libethash/ethash.h
@@ -137,7 +137,23 @@ ethash_return_value_t ethash_full_compute(
 );
 
 /**
- * Calculate the full client data
+ * Calculate the light client data of the ProgPow
+ *
+ * @param light          The light client handler
+ * @param header_hash    The header hash to pack into the mix
+ * @param nonce          The nonce to pack into the mix
+ * @param block_number   The block_number
+ * @return               an object of ethash_return_value_t holding the return values
+ */
+ethash_return_value_t progpow_light_compute(
+	ethash_light_t light,
+	ethash_h256_t const header_hash,
+	uint64_t nonce,
+	uint64_t block_number
+);
+
+/**
+ * Calculate the full client data of the ProgPoW
  *
  * @param full           The full client handler
  * @param header_hash    The header hash to pack into the mix
diff --git a/src/libethash/internal.h b/src/libethash/internal.h
index 484764f4..9938a542 100644
--- a/src/libethash/internal.h
+++ b/src/libethash/internal.h
@@ -122,22 +122,7 @@ uint32_t progpowMath(uint32_t a, uint32_t b, uint32_t r);
 void merge(uint32_t *a, uint32_t b, uint32_t r);
 
 /**
- * Calculate the light client data
- *
- * @param light          The light client handler
- * @param header_hash    The header hash to pack into the mix
- * @param nonce          The nonce to pack into the mix
- * @return               an object of ethash_return_value_t holding the return values
- */
-ethash_return_value_t progpow_light_compute(
-	ethash_light_t light,
-	ethash_h256_t const header_hash,
-	uint64_t nonce,
-	uint64_t block_number
-);
-
-/**
- * Calculate the light client data. Internal version.
+ * Calculate the light client data of the ProgPow. Internal version.
  *
  * @param light          The light client handler
  * @param full_size      The size of the full data in bytes.