diff --git a/validator/val_secalgo.c b/validator/val_secalgo.c
index 763ef2cac..434b6870f 100644
--- a/validator/val_secalgo.c
+++ b/validator/val_secalgo.c
@@ -73,7 +73,7 @@
 #endif
 
 /* return size of digest if supported, or 0 otherwise */
-int
+size_t
 nsec3_hash_algo_size_supported(int id)
 {
 	switch(id) {
@@ -593,7 +593,7 @@ verify_canonrrset(sldns_buffer* buf, int algo, unsigned char* sigblock,
 #include "prerror.h"
 
 /* return size of digest if supported, or 0 otherwise */
-int
+size_t
 nsec3_hash_algo_size_supported(int id)
 {
 	switch(id) {
@@ -1135,7 +1135,7 @@ verify_canonrrset(sldns_buffer* buf, int algo, unsigned char* sigblock,
 #endif
 
 /* return size of digest if supported, or 0 otherwise */
-int
+size_t
 nsec3_hash_algo_size_supported(int id)
 {
 	switch(id) {
diff --git a/validator/val_secalgo.h b/validator/val_secalgo.h
index cba1cb4f6..589f1f11d 100644
--- a/validator/val_secalgo.h
+++ b/validator/val_secalgo.h
@@ -45,7 +45,7 @@
 struct sldns_buffer;
 
 /** Return size of nsec3 hash algorithm, 0 if not supported */
-int nsec3_hash_algo_size_supported(int id);
+size_t nsec3_hash_algo_size_supported(int id);
 
 /**
  * Hash a single hash call of an NSEC3 hash algorithm.