Clear the high bit the same way everywhere

src/libsodium/crypto_scalarmult/ed25519/ref10/scalarmult_ed25519_ref10.c

@@ -23,7 +23,7 @@ static inline void
 _crypto_scalarmult_ed25519_clamp(unsigned char k[32])
 {
     k[0] &= 248;
-    k[31] &= 63;
+    k[31] &= 127;
     k[31] |= 64;
 }
 

src/libsodium/crypto_sign/ed25519/ref10/keypair.c

@@ -21,7 +21,7 @@ crypto_sign_ed25519_seed_keypair(unsigned char *pk, unsigned char *sk,
     crypto_hash_sha512(sk, seed, 32);
 #endif
     sk[0] &= 248;
-    sk[31] &= 63;
+    sk[31] &= 127;
     sk[31] |= 64;
 
     ge_scalarmult_base(&A, sk);

src/libsodium/crypto_sign/ed25519/ref10/obsolete.c

@@ -19,7 +19,7 @@ crypto_sign_edwards25519sha512batch_keypair(unsigned char *pk,
     randombytes_buf(sk, 32);
     crypto_hash_sha512(sk, sk, 32);
     sk[0] &= 248;
-    sk[31] &= 63;
+    sk[31] &= 127;
     sk[31] |= 64;
     ge_scalarmult_base(&A, sk);
     ge_p3_tobytes(pk, &A);

src/libsodium/crypto_sign/ed25519/ref10/sign.c

@@ -28,7 +28,7 @@ static inline void
 _crypto_sign_ed25519_clamp(unsigned char k[32])
 {
     k[0] &= 248;
-    k[31] &= 63;
+    k[31] &= 127;
     k[31] |= 64;
 }