diff --git a/src/libsodium/crypto_sign/ed25519/ref10/sign.c b/src/libsodium/crypto_sign/ed25519/ref10/sign.c
index fa3080eb..25652ec1 100644
--- a/src/libsodium/crypto_sign/ed25519/ref10/sign.c
+++ b/src/libsodium/crypto_sign/ed25519/ref10/sign.c
@@ -13,14 +13,11 @@ crypto_sign_detached(unsigned char *sig, unsigned long long *siglen_p,
                      const unsigned char *sk)
 {
     crypto_hash_sha512_state hs;
-    unsigned char pk[32];
     unsigned char az[64];
     unsigned char nonce[64];
     unsigned char hram[64];
     ge_p3 R;
 
-    memmove(pk, sk + 32, 32);
-
     crypto_hash_sha512(az, sk, 32);
     az[0] &= 248;
     az[31] &= 63;
@@ -31,7 +28,7 @@ crypto_sign_detached(unsigned char *sig, unsigned long long *siglen_p,
     crypto_hash_sha512_update(&hs, m, mlen);
     crypto_hash_sha512_final(&hs, nonce);
 
-    memmove(sig + 32, pk, 32);
+    memmove(sig + 32, sk + 32, 32);
 
     sc_reduce(nonce);
     ge_scalarmult_base(&R, nonce);