diff --git a/src/ext/ed25519/donna/ed25519-hash-custom.h b/src/ext/ed25519/donna/ed25519-hash-custom.h
index 7dc249129d..609451abd5 100644
--- a/src/ext/ed25519/donna/ed25519-hash-custom.h
+++ b/src/ext/ed25519/donna/ed25519-hash-custom.h
@@ -9,3 +9,34 @@
 	void ed25519_hash(uint8_t *hash, const uint8_t *in, size_t inlen);
 */
 
+#include "crypto.h"
+
+typedef struct ed25519_hash_context {
+  crypto_digest_t *ctx;
+} ed25519_hash_context;
+
+
+static void
+ed25519_hash_init(ed25519_hash_context *ctx)
+{
+  ctx->ctx = crypto_digest512_new(DIGEST_SHA512);
+}
+static void
+ed25519_hash_update(ed25519_hash_context *ctx, const uint8_t *in, size_t inlen)
+{
+  crypto_digest_add_bytes(ctx->ctx, (const char *)in, inlen);
+}
+static void
+ed25519_hash_final(ed25519_hash_context *ctx, uint8_t *hash)
+{
+  crypto_digest_get_digest(ctx->ctx, (char *)hash, DIGEST512_LEN);
+  crypto_digest_free(ctx->ctx);
+  ctx->ctx = NULL;
+}
+static void
+ed25519_hash(uint8_t *hash, const uint8_t *in, size_t inlen)
+{
+  crypto_digest512((char *)hash, (const char *)in, inlen,
+		   DIGEST_SHA512);
+}
+
diff --git a/src/ext/ed25519/ref10/crypto_hash_sha512.h b/src/ext/ed25519/ref10/crypto_hash_sha512.h
index 0278571522..e454c4e7ef 100644
--- a/src/ext/ed25519/ref10/crypto_hash_sha512.h
+++ b/src/ext/ed25519/ref10/crypto_hash_sha512.h
@@ -1,30 +1,32 @@
 /* Added for Tor. */
-#include <openssl/sha.h>
+#include "crypto.h"
 
 /* Set 'out' to the 512-bit SHA512 hash of the 'len'-byte string in 'inp' */
 #define crypto_hash_sha512(out, inp, len) \
-  SHA512((inp), (len), (out))
+  crypto_digest512((char *)(out), (const char *)(inp), (len), DIGEST_SHA512)
 
 /* Set 'out' to the 512-bit SHA512 hash of the 'len1'-byte string in 'inp1',
  * concatenated with the 'len2'-byte string in 'inp2'. */
 #define crypto_hash_sha512_2(out, inp1, len1, inp2, len2)               \
   do {                                                                  \
-      SHA512_CTX sha_ctx_;                                              \
-      SHA512_Init(&sha_ctx_);                                           \
-      SHA512_Update(&sha_ctx_, (inp1), (len1));                         \
-      SHA512_Update(&sha_ctx_, (inp2), (len2));                         \
-      SHA512_Final((out), &sha_ctx_);                                   \
- } while(0)
+    crypto_digest_t *sha_ctx_;						\
+    sha_ctx_ = crypto_digest512_new(DIGEST_SHA512);			\
+    crypto_digest_add_bytes(sha_ctx_, (const char *)(inp1), (len1));	\
+    crypto_digest_add_bytes(sha_ctx_, (const char *)(inp2), (len2));	\
+    crypto_digest_get_digest(sha_ctx_, (char *)out, 64);		\
+    crypto_digest_free(sha_ctx_);					\
+  } while (0)
 
 /* Set 'out' to the 512-bit SHA512 hash of the 'len1'-byte string in 'inp1',
  * concatenated with the 'len2'-byte string in 'inp2', concatenated with
  * the 'len3'-byte string in 'len3'. */
 #define crypto_hash_sha512_3(out, inp1, len1, inp2, len2, inp3, len3)   \
   do {                                                                  \
-      SHA512_CTX sha_ctx_;                                              \
-      SHA512_Init(&sha_ctx_);                                           \
-      SHA512_Update(&sha_ctx_, (inp1), (len1));                         \
-      SHA512_Update(&sha_ctx_, (inp2), (len2));                         \
-      SHA512_Update(&sha_ctx_, (inp3), (len3));                         \
-      SHA512_Final((out), &sha_ctx_);                                   \
+    crypto_digest_t *sha_ctx_;						\
+    sha_ctx_ = crypto_digest512_new(DIGEST_SHA512);			\
+    crypto_digest_add_bytes(sha_ctx_, (const char *)(inp1), (len1));	\
+    crypto_digest_add_bytes(sha_ctx_, (const char *)(inp2), (len2));	\
+    crypto_digest_add_bytes(sha_ctx_, (const char *)(inp3), (len3));	\
+    crypto_digest_get_digest(sha_ctx_, (char *)out, 64);		\
+    crypto_digest_free(sha_ctx_);					\
  } while(0)
diff --git a/src/ext/include.am b/src/ext/include.am
index c18e58857e..7ec2e43312 100644
--- a/src/ext/include.am
+++ b/src/ext/include.am
@@ -101,6 +101,7 @@ noinst_LIBRARIES += $(LIBED25519_REF10)
 src_ext_ed25519_donna_libed25519_donna_a_CFLAGS=\
   @CFLAGS_CONSTTIME@ \
   -DED25519_CUSTOMRANDOM \
+  -DED25519_CUSTOMHASH \
   -DED25519_SUFFIX=_donna
 
 src_ext_ed25519_donna_libed25519_donna_a_SOURCES= \