diff --git a/include/libssh/sntrup761.h b/include/libssh/sntrup761.h
index 96e9ce0c..aa05a9fd 100644
--- a/include/libssh/sntrup761.h
+++ b/include/libssh/sntrup761.h
@@ -35,10 +35,6 @@ extern "C" {
 #define HAVE_SNTRUP761 1
 #endif
 
-extern void crypto_hash_sha512(unsigned char *out,
-                               const unsigned char *in,
-                               unsigned long long inlen);
-
 /*
  * Derived from public domain source, written by (in alphabetical order):
  * - Daniel J. Bernstein
diff --git a/src/external/sntrup761.c b/src/external/sntrup761.c
index b9bf7239..2f45622d 100644
--- a/src/external/sntrup761.c
+++ b/src/external/sntrup761.c
@@ -27,9 +27,7 @@ sntrup761_enc (uint8_t *c, uint8_t *k, const uint8_t *pk,
 void
 sntrup761_dec (uint8_t *k, const uint8_t *c, const uint8_t *sk);
 
-extern void crypto_hash_sha512 (unsigned char *out,
-				const unsigned char *in,
-				unsigned long long inlen);
+extern int sha512(const unsigned char *digest, size_t len, unsigned char *hash);
 
 #define MAX_LEN 761
 
@@ -701,7 +699,7 @@ Hash_prefix (unsigned char *out, int b, const unsigned char *in, int inlen)
   x[0] = b;
   for (i = 0; i < inlen; ++i)
     x[i + 1] = in[i];
-  crypto_hash_sha512 (h, x, inlen + 1);
+  sha512 (x, inlen + 1, h);
   for (i = 0; i < 32; ++i)
     out[i] = h[i];
 }
diff --git a/src/sntrup761.c b/src/sntrup761.c
index bc96439a..a67de437 100644
--- a/src/sntrup761.c
+++ b/src/sntrup761.c
@@ -37,13 +37,6 @@
 #include "libssh/session.h"
 #include "libssh/ssh2.h"
 
-void crypto_hash_sha512(unsigned char *out,
-                        const unsigned char *in,
-                        unsigned long long inlen)
-{
-    sha512(in, inlen, out);
-}
-
 #ifndef HAVE_LIBGCRYPT
 static void crypto_random(void *ctx, size_t length, uint8_t *dst)
 {