diff --git a/src/libsodium/crypto_sign/ed25519/ref10/obsolete.c b/src/libsodium/crypto_sign/ed25519/ref10/obsolete.c
index 98b37b75..62aa7b83 100644
--- a/src/libsodium/crypto_sign/ed25519/ref10/obsolete.c
+++ b/src/libsodium/crypto_sign/ed25519/ref10/obsolete.c
@@ -107,7 +107,7 @@ int crypto_sign_edwards25519sha512batch_open(unsigned char *m,
         return -1;
     }
     *mlen_p = mlen;
-    memmove(m, sm + 64, mlen);
+    memmove(m, sm + 32, mlen);
 
     return 0;
 }