Correct Unit problem
diff --git a/src/MacMessage.c b/src/MacMessage.c
index ed287d9..830ae9c 100644
--- a/src/MacMessage.c
+++ b/src/MacMessage.c
@@ -539,19 +539,19 @@
 
 	switch (alg) {
 	case COSE_Algorithm_HMAC_256_256:
-		if (!HMAC_Validate(pcose, 256, 256, pbKey, cbitKey, pbAuthData, cbAuthData, perr)) goto errorReturn;
+		if (!HMAC_Validate(pcose, 256, 256, pbKey, cbitKey/8, pbAuthData, cbAuthData, perr)) goto errorReturn;
 		break;
 
 	case COSE_Algorithm_HMAC_256_64:
-		if (!HMAC_Validate(pcose, 256, 64, pbKey, cbitKey, pbAuthData, cbAuthData, perr)) goto errorReturn;
+		if (!HMAC_Validate(pcose, 256, 64, pbKey, cbitKey/8, pbAuthData, cbAuthData, perr)) goto errorReturn;
 		break;
 
 	case COSE_Algorithm_HMAC_384_384:
-		if (!HMAC_Validate(pcose, 384, 384, pbKey, cbitKey, pbAuthData, cbAuthData, perr)) goto errorReturn;
+		if (!HMAC_Validate(pcose, 384, 384, pbKey, cbitKey/8, pbAuthData, cbAuthData, perr)) goto errorReturn;
 		break;
 
 	case COSE_Algorithm_HMAC_512_512:
-		if (!HMAC_Validate(pcose, 512, 512, pbKey, cbitKey, pbAuthData, cbAuthData, perr)) goto errorReturn;
+		if (!HMAC_Validate(pcose, 512, 512, pbKey, cbitKey/8, pbAuthData, cbAuthData, perr)) goto errorReturn;
 		break;
 
 	case COSE_Algorithm_CBC_MAC_128_64: