diff --git a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/fe51.h b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/fe51.h
index 5ef8a439..7e88ef9c 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/fe51.h
+++ b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/fe51.h
@@ -8,6 +8,10 @@
 #ifndef fe51_H
 #define fe51_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "crypto_uint64.h"
 #include "fe51_namespace.h"
 
@@ -22,4 +26,8 @@ extern void fe51_mul(fe51 *, const fe51 *, const fe51 *);
 extern void fe51_nsquare(fe51 *, const fe51 *, int);
 extern void fe51_invert(fe51 *, const fe51 *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder.h b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder.h
index cacfabbe..1912500b 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder.h
+++ b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder.h
@@ -1,10 +1,18 @@
 #ifndef ladder_H
 #define ladder_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "fe.h"
 #include "ladder_namespace.h"
 
 extern void ladder(fe *, const unsigned char *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif //ifndef ladder_H
 
diff --git a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder_base.h b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder_base.h
index 88b168de..09b5fe79 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder_base.h
+++ b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/ladder_base.h
@@ -1,10 +1,18 @@
 #ifndef ladder_base_H
 #define ladder_base_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "fe.h"
 #include "ladder_base_namespace.h"
 
 extern void ladder_base(fe *, const unsigned char *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif //ifndef ladder_base_H