diff --git a/ChangeLog b/ChangeLog
index e38d5c7870bc76a1992c4dcda66028a416062eb8..389bf21a133aaaf5914e1739b62b0cb00be15f97 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2016-01-10  Niels Möller  <nisse@lysator.liu.se>
 
+	* base64-encode.c (encode_raw): Use const uint8_t * for the
+	alphabet argument.
+
 	* nettle.texinfo (RSA): Document the rsa_pkcs1_verify and
 	rsa_pkcs1_sign functions, and the new rsa_*_tr functions.
 
diff --git a/base64-encode.c b/base64-encode.c
index 0e81b3f5e1abe3bd682e2751ce1170891c174910..f23115a9ff9bb8655ec2bef77232af847ced723c 100644
--- a/base64-encode.c
+++ b/base64-encode.c
@@ -41,7 +41,7 @@
 #define ENCODE(alphabet,x) ((alphabet)[0x3F & (x)])
 
 static void
-encode_raw(const char *alphabet,
+encode_raw(const uint8_t *alphabet,
 	   uint8_t *dst, size_t length, const uint8_t *src)
 {
   const uint8_t *in = src + length;