diff --git a/src/libsodium/crypto_sign/ed25519/ref10/keypair.c b/src/libsodium/crypto_sign/ed25519/ref10/keypair.c
index c5ad1191..359faadb 100644
--- a/src/libsodium/crypto_sign/ed25519/ref10/keypair.c
+++ b/src/libsodium/crypto_sign/ed25519/ref10/keypair.c
@@ -3,21 +3,40 @@
 #include "crypto_hash_sha512.h"
 #include "ge.h"
 
-int crypto_sign_keypair(unsigned char *pk,unsigned char *sk)
+int crypto_sign_seed_keypair(unsigned char *pk, unsigned char *sk,
+                             const unsigned char *seed)
 {
-  unsigned char h[64];
-  ge_p3 A;
-  int i;
+    ge_p3 A;
+    int i;
 
-  randombytes(sk,32);
-  crypto_hash_sha512(h,sk,32);
-  h[0] &= 248;
-  h[31] &= 63;
-  h[31] |= 64;
+    crypto_hash_sha512(sk,seed,32);
+    sk[0] &= 248;
+    sk[31] &= 63;
+    sk[31] |= 64;
 
-  ge_scalarmult_base(&A,h);
-  ge_p3_tobytes(pk,&A);
+    ge_scalarmult_base(&A,sk);
+    ge_p3_tobytes(pk,&A);
 
-  for (i = 0;i < 32;++i) sk[32 + i] = pk[i];
-  return 0;
+    for (i = 0;i < 32;++i) sk[i] = seed[i];
+    for (i = 0;i < 32;++i) sk[32 + i] = pk[i];
+    return 0;
+}
+
+int crypto_sign_keypair(unsigned char *pk, unsigned char *sk)
+{
+    unsigned char h[64];
+    ge_p3 A;
+    int i;
+
+    randombytes(sk,32);
+    crypto_hash_sha512(h,sk,32);
+    h[0] &= 248;
+    h[31] &= 63;
+    h[31] |= 64;
+
+    ge_scalarmult_base(&A,h);
+    ge_p3_tobytes(pk,&A);
+
+    for (i = 0;i < 32;++i) sk[32 + i] = pk[i];
+    return 0;
 }