diff --git a/src/libsodium/crypto_box/crypto_box_seal.c b/src/libsodium/crypto_box/crypto_box_seal.c
index e01d6498..9a677d00 100644
--- a/src/libsodium/crypto_box/crypto_box_seal.c
+++ b/src/libsodium/crypto_box/crypto_box_seal.c
@@ -37,8 +37,6 @@ crypto_box_seal(unsigned char *c, const unsigned char *m,
                           nonce, pk, esk);
     memcpy(c, epk, crypto_box_PUBLICKEYBYTES);
     sodium_memzero(esk, sizeof esk);
-    sodium_memzero(epk, sizeof epk);
-    sodium_memzero(nonce, sizeof nonce);
 
     return ret;
 }
diff --git a/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_curve25519xchacha20poly1305.c b/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_curve25519xchacha20poly1305.c
index 5e2532ea..789286e0 100644
--- a/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_curve25519xchacha20poly1305.c
+++ b/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_curve25519xchacha20poly1305.c
@@ -48,7 +48,10 @@ crypto_box_curve25519xchacha20poly1305_beforenm(unsigned char *k,
     if (crypto_scalarmult_curve25519(s, sk, pk) != 0) {
         return -1;
     }
-    return crypto_core_hchacha20(k, zero, s, NULL);
+    crypto_core_hchacha20(k, zero, s, NULL);
+    sodium_memzero(s, sizeof s);
+
+    return 0;
 }
 
 int
diff --git a/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_seal_curve25519xchacha20poly1305.c b/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_seal_curve25519xchacha20poly1305.c
index 0240f036..0b63431b 100644
--- a/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_seal_curve25519xchacha20poly1305.c
+++ b/src/libsodium/crypto_box/curve25519xchacha20poly1305/box_seal_curve25519xchacha20poly1305.c
@@ -44,8 +44,6 @@ crypto_box_curve25519xchacha20poly1305_seal(unsigned char *c, const unsigned cha
          nonce, pk, esk);
     memcpy(c, epk, crypto_box_curve25519xchacha20poly1305_PUBLICKEYBYTES);
     sodium_memzero(esk, sizeof esk);
-    sodium_memzero(epk, sizeof epk);
-    sodium_memzero(nonce, sizeof nonce);
 
     return ret;
 }
diff --git a/src/libsodium/crypto_box/curve25519xsalsa20poly1305/box_curve25519xsalsa20poly1305.c b/src/libsodium/crypto_box/curve25519xsalsa20poly1305/box_curve25519xsalsa20poly1305.c
index 4c1d62ed..c8d7fe01 100644
--- a/src/libsodium/crypto_box/curve25519xsalsa20poly1305/box_curve25519xsalsa20poly1305.c
+++ b/src/libsodium/crypto_box/curve25519xsalsa20poly1305/box_curve25519xsalsa20poly1305.c
@@ -42,7 +42,10 @@ crypto_box_curve25519xsalsa20poly1305_beforenm(unsigned char *k,
     if (crypto_scalarmult_curve25519(s, sk, pk) != 0) {
         return -1;
     }
-    return crypto_core_hsalsa20(k, zero, s, NULL);
+    crypto_core_hsalsa20(k, zero, s, NULL);
+    sodium_memzero(s, sizeof s);
+
+    return 0;
 }
 
 int