diff --git a/src/libsodium/crypto_box/crypto_box_easy.c b/src/libsodium/crypto_box/crypto_box_easy.c
index 2992db80..4687cf90 100644
--- a/src/libsodium/crypto_box/crypto_box_easy.c
+++ b/src/libsodium/crypto_box/crypto_box_easy.c
@@ -24,11 +24,11 @@ crypto_box_easy(unsigned char *c, const unsigned char *m,
     (void) sizeof(char[crypto_box_ZEROBYTES >=
                        crypto_box_BOXZEROBYTES ? 1 : -1]);
     m_boxed_len = (size_t) mlen + crypto_box_ZEROBYTES;
-    if ((m_boxed = malloc((size_t) m_boxed_len)) == NULL) {
+    if ((m_boxed = (unsigned char *) malloc((size_t) m_boxed_len)) == NULL) {
         return -1;
     }
     c_boxed_len = (size_t) mlen + crypto_box_ZEROBYTES;
-    if ((c_boxed = malloc(c_boxed_len)) == NULL) {
+    if ((c_boxed = (unsigned char *) malloc(c_boxed_len)) == NULL) {
         free(m_boxed);
         return -1;
     }
@@ -65,13 +65,13 @@ crypto_box_open_easy(unsigned char *m, const unsigned char *c,
         return -1;
     }
     c_boxed_len = clen + crypto_box_BOXZEROBYTES;
-    if ((c_boxed = malloc(c_boxed_len)) == NULL) {
+    if ((c_boxed = (unsigned char *) malloc(c_boxed_len)) == NULL) {
         return -1;
     }
     memset(c_boxed, 0, crypto_box_BOXZEROBYTES);
     memcpy(c_boxed + crypto_box_BOXZEROBYTES, c, clen);
     m_boxed_len = c_boxed_len + crypto_box_MACBYTES;
-    if ((m_boxed = malloc(m_boxed_len)) == NULL) {
+    if ((m_boxed = (unsigned char *) malloc(m_boxed_len)) == NULL) {
         return -1;
     }
     rc = crypto_box_open(m_boxed, c_boxed,