diff --git a/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c b/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
index 73c381cd..e0fe757a 100644
--- a/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
+++ b/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
@@ -583,8 +583,8 @@ crypto_aead_aes256gcm_beforenm(crypto_aead_aes256gcm_state *ctx_, const unsigned
 {
     aes256gcm_state *ctx   = (aes256gcm_state *) (void *) ctx_;
     unsigned char *  H     = ctx->H;
-    __m128i *        rkeys = ctx->rkeys;
-    __m128i          zero  = _mm_setzero_si128();
+    const __m128i *  rkeys = ctx->rkeys;
+    const __m128i    zero  = _mm_setzero_si128();
 
     COMPILER_ASSERT((sizeof *ctx_) >= (sizeof *ctx));
     aesni_key256_expand(k, rkeys);