diff --git a/lib/isc/crc64.c b/lib/isc/crc64.c
index 8869a5cc0e..cfabc9800d 100644
--- a/lib/isc/crc64.c
+++ b/lib/isc/crc64.c
@@ -122,15 +122,13 @@ isc_crc64_init(isc_uint64_t *crc) {
 }
 
 void
-isc_crc64_update(isc_uint64_t *crc, const isc_uint8_t *data, size_t len) {
-	unsigned char *p;
+isc_crc64_update(isc_uint64_t *crc, const void *data, size_t len) {
+	const unsigned char *p = data;
 	int i;
 
 	REQUIRE(crc != NULL);
 	REQUIRE(data != NULL);
 
-	DE_CONST(data, p);
-
 	while (len-- > 0) {
 		i = ((int) (*crc >> 56) ^ *p++) & 0xff;
 		*crc = crc64_table[i] ^ (*crc << 8);
diff --git a/lib/isc/include/isc/crc64.h b/lib/isc/include/isc/crc64.h
index 0403fec08e..18efb71923 100644
--- a/lib/isc/include/isc/crc64.h
+++ b/lib/isc/include/isc/crc64.h
@@ -36,7 +36,7 @@ isc_crc64_init(isc_uint64_t *crc);
  */
 
 void
-isc_crc64_update(isc_uint64_t *crc, const isc_uint8_t *data, size_t len);
+isc_crc64_update(isc_uint64_t *crc, const void *data, size_t len);
 /*%
  * Add data to the CRC.
  *