diff --git a/src/base64.c b/src/base64.c
index 9a33ebd..c33057a 100644
--- a/src/base64.c
+++ b/src/base64.c
@@ -229,20 +229,20 @@ static inline bool _encode(const uint8_t *input, size_t inlen, char **output, si
 
 // interface functions
 
-bool cjose_base64_encode(const uint8_t *input, size_t inlen, char **output, size_t *outlen, cjose_err *err)
+bool cjose_base64_encode(const uint8_t *input, const size_t inlen, char **output, size_t *outlen, cjose_err *err)
 {
     return _encode(input, inlen, output, outlen, ALPHABET_B64, err);
 }
-bool cjose_base64url_encode(const uint8_t *input, size_t inlen, char **output, size_t *outlen, cjose_err *err)
+bool cjose_base64url_encode(const uint8_t *input, const size_t inlen, char **output, size_t *outlen, cjose_err *err)
 {
     return _encode(input, inlen, output, outlen, ALPHABET_B64U, err);
 }
 
-bool cjose_base64_decode(const char *input, size_t inlen, uint8_t **output, size_t *outlen, cjose_err *err)
+bool cjose_base64_decode(const char *input, const size_t inlen, uint8_t **output, size_t *outlen, cjose_err *err)
 {
     return _decode(input, inlen, output, outlen, false, err);
 }
-bool cjose_base64url_decode(const char *input, size_t inlen, uint8_t **output, size_t *outlen, cjose_err *err)
+bool cjose_base64url_decode(const char *input, const size_t inlen, uint8_t **output, size_t *outlen, cjose_err *err)
 {
     return _decode(input, inlen, output, outlen, true, err);
 }
diff --git a/src/include/concatkdf_int.h b/src/include/concatkdf_int.h
index fe147f9..aaffbfd 100644
--- a/src/include/concatkdf_int.h
+++ b/src/include/concatkdf_int.h
@@ -14,7 +14,7 @@
 #include <cjose/header.h>
 
 bool cjose_concatkdf_create_otherinfo(const char *alg,
-                                      size_t keylen,
+                                      const size_t keylen,
                                       cjose_header_t *hdr,
                                       uint8_t **otherinfo, size_t *otherinfoLen,
                                       cjose_err *err);
diff --git a/src/jws.c b/src/jws.c
index 4e03554..88038e4 100644
--- a/src/jws.c
+++ b/src/jws.c
@@ -59,10 +59,10 @@ static bool _cjose_jws_build_hdr(cjose_jws_t *jws, cjose_header_t *header, cjose
     }
     if (!cjose_base64url_encode((const uint8_t *)hdr_str, strlen(hdr_str), &jws->hdr_b64u, &jws->hdr_b64u_len, err))
     {
-        free(hdr_str);
+        cjose_get_dealloc()(hdr_str);
         return false;
     }
-    free(hdr_str);
+    cjose_get_dealloc()(hdr_str);
 
     return true;
 }