diff --git a/src/libsodium/crypto_core/ed25519/core_ed25519.c b/src/libsodium/crypto_core/ed25519/core_ed25519.c
index 666f0fc0..f17cda13 100644
--- a/src/libsodium/crypto_core/ed25519/core_ed25519.c
+++ b/src/libsodium/crypto_core/ed25519/core_ed25519.c
@@ -88,7 +88,7 @@ crypto_core_ed25519_scalar_invert(unsigned char *recip, const unsigned char *s)
 
 void
 crypto_core_ed25519_scalar_reduce(unsigned char *r,
-                                  const unsigned char s[crypto_core_ed25519_NONREDUCEDSCALARBYTES])
+                                  const unsigned char *s)
 {
     unsigned char t[crypto_core_ed25519_NONREDUCEDSCALARBYTES];
 
diff --git a/src/libsodium/include/sodium/crypto_core_ed25519.h b/src/libsodium/include/sodium/crypto_core_ed25519.h
index 9513f58b..b3958c7e 100644
--- a/src/libsodium/include/sodium/crypto_core_ed25519.h
+++ b/src/libsodium/include/sodium/crypto_core_ed25519.h
@@ -47,7 +47,7 @@ void crypto_core_ed25519_scalar_random(unsigned char *r)
             __attribute__ ((nonnull));
 
 SODIUM_EXPORT
-int crypto_core_ed25519_scalar_invert(unsigned char *recip, const unsigned char s[64])
+int crypto_core_ed25519_scalar_invert(unsigned char *recip, const unsigned char *s)
             __attribute__ ((nonnull));
 
 /*
@@ -55,7 +55,7 @@ int crypto_core_ed25519_scalar_invert(unsigned char *recip, const unsigned char
  * uniformity of `r` over `L`.
  */
 SODIUM_EXPORT
-void crypto_core_ed25519_scalar_reduce(unsigned char *r, const unsigned char s[64])
+void crypto_core_ed25519_scalar_reduce(unsigned char *r, const unsigned char *s)
             __attribute__ ((nonnull));
 
 #ifdef __cplusplus