diff --git a/cpu-miner.c b/cpu-miner.c
index f9be60cd..c3924a9d 100644
--- a/cpu-miner.c
+++ b/cpu-miner.c
@@ -308,7 +308,7 @@ static void *miner_thread(void *thr_id_int)
 		switch (opt_algo) {
 		case ALGO_C:
 			rc = scanhash_c(work.midstate, work.data + 64,
-				        work.hash1, work.hash,
+				        work.hash1, work.hash, work.target,
 					max_nonce, &hashes_done);
 			break;
 
@@ -317,6 +317,7 @@ static void *miner_thread(void *thr_id_int)
 			unsigned int rc4 =
 				ScanHash_4WaySSE2(work.midstate, work.data + 64,
 						  work.hash1, work.hash,
+						  work.target,
 						  max_nonce, &hashes_done);
 			rc = (rc4 == -1) ? false : true;
 			}
@@ -325,19 +326,20 @@ static void *miner_thread(void *thr_id_int)
 
 #ifdef WANT_VIA_PADLOCK
 		case ALGO_VIA:
-			rc = scanhash_via(work.data, max_nonce, &hashes_done);
+			rc = scanhash_via(work.data, work.target,
+					  max_nonce, &hashes_done);
 			break;
 #endif
 		case ALGO_CRYPTOPP:
 			rc = scanhash_cryptopp(work.midstate, work.data + 64,
-				        work.hash1, work.hash,
+				        work.hash1, work.hash, work.target,
 					max_nonce, &hashes_done);
 			break;
 
 #ifdef WANT_CRYPTOPP_ASM32
 		case ALGO_CRYPTOPP_ASM32:
 			rc = scanhash_asm32(work.midstate, work.data + 64,
-				        work.hash1, work.hash,
+				        work.hash1, work.hash, work.target,
 					max_nonce, &hashes_done);
 			break;
 #endif
diff --git a/miner.h b/miner.h
index 49bc07d0..539b5d6f 100644
--- a/miner.h
+++ b/miner.h
@@ -52,24 +52,29 @@ extern bool hex2bin(unsigned char *p, const char *hexstr, size_t len);
 
 extern unsigned int ScanHash_4WaySSE2(const unsigned char *pmidstate,
 	unsigned char *pdata, unsigned char *phash1, unsigned char *phash,
+	const unsigned char *ptarget,
 	uint32_t max_nonce, unsigned long *nHashesDone);
 
 extern bool scanhash_via(unsigned char *data_inout,
+	const unsigned char *target,
 	uint32_t max_nonce, unsigned long *hashes_done);
 
 extern bool scanhash_c(const unsigned char *midstate, unsigned char *data,
 	      unsigned char *hash1, unsigned char *hash,
+	      const unsigned char *target,
 	      uint32_t max_nonce, unsigned long *hashes_done);
 extern bool scanhash_cryptopp(const unsigned char *midstate,unsigned char *data,
 	      unsigned char *hash1, unsigned char *hash,
+	      const unsigned char *target,
 	      uint32_t max_nonce, unsigned long *hashes_done);
 extern bool scanhash_asm32(const unsigned char *midstate,unsigned char *data,
 	      unsigned char *hash1, unsigned char *hash,
+	      const unsigned char *target,
 	      uint32_t max_nonce, unsigned long *hashes_done);
 
 extern int
 timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y);
 
-extern void print_pow(const unsigned char *hash);
+extern bool fulltest(const unsigned char *hash, const unsigned char *target);
 
 #endif /* __MINER_H__ */
diff --git a/sha256_4way.c b/sha256_4way.c
index 556a07ad..fe9642bc 100644
--- a/sha256_4way.c
+++ b/sha256_4way.c
@@ -100,6 +100,7 @@ static const unsigned int pSHA256InitState[8] =
 
 unsigned int ScanHash_4WaySSE2(const unsigned char *pmidstate, unsigned char *pdata,
 	unsigned char *phash1, unsigned char *phash,
+	const unsigned char *ptarget,
 	uint32_t max_nonce, unsigned long *nHashesDone)
 {
     unsigned int *nNonce_p = (unsigned int*)(pdata + 12);
@@ -124,11 +125,11 @@ unsigned int ScanHash_4WaySSE2(const unsigned char *pmidstate, unsigned char *pd
                 for (i = 0; i < 32/4; i++)
                     ((unsigned int*)phash)[i] = thash[i][j];
 
-		print_pow(phash);
-
-		*nHashesDone = nonce;
-		*nNonce_p = nonce + j;
-                return nonce + j;
+		if (fulltest(phash, ptarget)) {
+			*nHashesDone = nonce;
+			*nNonce_p = nonce + j;
+                	return nonce + j;
+		}
             }
         }
 
diff --git a/sha256_cryptopp.c b/sha256_cryptopp.c
index 4ada4807..47d4921a 100644
--- a/sha256_cryptopp.c
+++ b/sha256_cryptopp.c
@@ -93,6 +93,7 @@ static void runhash(void *state, const void *input, const void *init)
 /* suspiciously similar to ScanHash* from bitcoin */
 bool scanhash_cryptopp(const unsigned char *midstate, unsigned char *data,
 	        unsigned char *hash1, unsigned char *hash,
+		const unsigned char *target,
 	        uint32_t max_nonce, unsigned long *hashes_done)
 {
 	uint32_t *hash32 = (uint32_t *) hash;
@@ -109,9 +110,7 @@ bool scanhash_cryptopp(const unsigned char *midstate, unsigned char *data,
 
 		stat_ctr++;
 
-		if (hash32[7] == 0) {
-			print_pow(hash);
-
+		if ((hash32[7] == 0) && fulltest(hash, target)) {
 			*hashes_done = stat_ctr;
 			return true;
 		}
@@ -578,6 +577,7 @@ static void runhash32(void *state, const void *input, const void *init)
 /* suspiciously similar to ScanHash* from bitcoin */
 bool scanhash_asm32(const unsigned char *midstate, unsigned char *data,
 	        unsigned char *hash1, unsigned char *hash,
+		const unsigned char *target,
 	        uint32_t max_nonce, unsigned long *hashes_done)
 {
 	uint32_t *hash32 = (uint32_t *) hash;
@@ -594,8 +594,8 @@ bool scanhash_asm32(const unsigned char *midstate, unsigned char *data,
 
 		stat_ctr++;
 
-		if (hash32[7] == 0) {
-			print_pow(hash);
+		if ((hash32[7] == 0) && fulltest(hash, target)) {
+			fulltest(hash, target);
 
 			*hashes_done = stat_ctr;
 			return true;
diff --git a/sha256_generic.c b/sha256_generic.c
index 91fbbcf5..cc23fc18 100644
--- a/sha256_generic.c
+++ b/sha256_generic.c
@@ -239,6 +239,7 @@ const uint32_t sha256_init_state[8] = {
 /* suspiciously similar to ScanHash* from bitcoin */
 bool scanhash_c(const unsigned char *midstate, unsigned char *data,
 	        unsigned char *hash1, unsigned char *hash,
+		const unsigned char *target,
 	        uint32_t max_nonce, unsigned long *hashes_done)
 {
 	uint32_t *hash32 = (uint32_t *) hash;
@@ -255,9 +256,7 @@ bool scanhash_c(const unsigned char *midstate, unsigned char *data,
 
 		stat_ctr++;
 
-		if (hash32[7] == 0) {
-			print_pow(hash);
-
+		if ((hash32[7] == 0) && fulltest(hash, target)) {
 			*hashes_done = stat_ctr;
 			return true;
 		}
diff --git a/sha256_via.c b/sha256_via.c
index 011d854d..a15c6645 100644
--- a/sha256_via.c
+++ b/sha256_via.c
@@ -18,6 +18,7 @@ static void via_sha256(void *hash, void *buf, unsigned len)
 }
 
 bool scanhash_via(unsigned char *data_inout,
+		  const unsigned char *target,
 		  uint32_t max_nonce, unsigned long *hashes_done)
 {
 	unsigned char data[128] __attribute__((aligned(128)));
@@ -56,9 +57,7 @@ bool scanhash_via(unsigned char *data_inout,
 
 		stat_ctr++;
 
-		if (hash32[7] == 0) {
-			print_pow(tmp_hash);
-
+		if ((hash32[7] == 0) && fulltest(tmp_hash, target)) {
 			/* swap nonce'd data back into original storage area;
 			 * TODO: only swap back the nonce, rather than all data
 			 */
diff --git a/util.c b/util.c
index 2a52a048..e37c0a0a 100644
--- a/util.c
+++ b/util.c
@@ -255,14 +255,45 @@ timeval_subtract (
   return x->tv_sec < y->tv_sec;
 }
 
-void print_pow(const unsigned char *hash)
+bool fulltest(const unsigned char *hash, const unsigned char *target)
 {
-	char *hexstr;
-	unsigned char hash_swap[32];
+	unsigned char hash_swap[32], target_swap[32];
+	uint32_t *hash32 = (uint32_t *) hash_swap;
+	uint32_t *target32 = (uint32_t *) target_swap;
+	int i;
+	bool rc = true;
+	char *hash_str, *target_str;
 
 	swap256(hash_swap, hash);
-	hexstr = bin2hex(hash_swap, 32);
-	fprintf(stderr, "PoW found: %s\n", hexstr);
-	free(hexstr);
-}
+	swap256(target_swap, target);
+
+	for (i = 0; i < 32/4; i++) {
+		uint32_t h32tmp = swab32(hash32[i]);
+		uint32_t t32tmp = target32[i];
+
+		target32[i] = swab32(target32[i]);	/* for printing */
+
+		if (h32tmp > t32tmp) {
+			rc = false;
+			break;
+		}
+		if (h32tmp < t32tmp) {
+			rc = true;
+			break;
+		}
+	}
+
+	hash_str = bin2hex(hash_swap, 32);
+	target_str = bin2hex(target_swap, 32);
 
+	fprintf(stderr, " Proof: %s\nTarget: %s\nTrgVal? %s\n",
+		hash_str,
+		target_str,
+		rc ? "YES (hash < target)" :
+		     "no (false positive; hash > target)");
+
+	free(hash_str);
+	free(target_str);
+
+	return rc;
+}