diff --git a/src/libsodium/crypto_scalarmult/curve25519/scalarmult_curve25519_api.c b/src/libsodium/crypto_scalarmult/curve25519/scalarmult_curve25519_api.c
index 10dc5808..eb2445b1 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/scalarmult_curve25519_api.c
+++ b/src/libsodium/crypto_scalarmult/curve25519/scalarmult_curve25519_api.c
@@ -1 +1,13 @@
 #include "crypto_scalarmult_curve25519.h"
+
+size_t
+crypto_scalarmult_curve25519_bytes(void)
+{
+    return crypto_scalarmult_curve25519_BYTES;
+}
+
+size_t
+crypto_scalarmult_curve25519_scalarbytes(void)
+{
+    return crypto_scalarmult_curve25519_SCALARBYTES;
+}
diff --git a/src/libsodium/include/sodium/crypto_scalarmult_curve25519.h.in b/src/libsodium/include/sodium/crypto_scalarmult_curve25519.h.in
index e87657ff..1266870d 100644
--- a/src/libsodium/include/sodium/crypto_scalarmult_curve25519.h.in
+++ b/src/libsodium/include/sodium/crypto_scalarmult_curve25519.h.in
@@ -7,6 +7,8 @@
 # endif
 #endif
 
+#include <stddef.h>
+
 #include "export.h"
 
 #define crypto_scalarmult_curve25519_BYTES 32
@@ -30,6 +32,12 @@ int crypto_scalarmult_curve25519_base(unsigned char *,const unsigned char *);
 # define crypto_scalarmult_curve25519_ref_base crypto_scalarmult_curve25519_base
 #endif
 
+SODIUM_EXPORT
+size_t crypto_scalarmult_curve25519_bytes(void);
+
+SODIUM_EXPORT
+size_t crypto_scalarmult_curve25519_scalarbytes(void);
+
 #ifdef __cplusplus
 }
 #endif