Merge pull request #34 from tewinget/master

Add electrum-seed wallet backup/recovery

1 files changed, 23 insertions, 2 deletions

diff --git a/src/crypto/crypto.cpp b/src/crypto/crypto.cpp
index f5f525700..98a17a3e4 100644
--- a/src/crypto/crypto.cpp
+++ b/src/crypto/crypto.cpp
@@ -50,6 +50,7 @@ namespace crypto {
     return &reinterpret_cast<const unsigned char &>(scalar);
   }
 
+  /* generate a random 32-byte (256-bit) integer and copy it to res */
   static inline void random_scalar(ec_scalar &res) {
     unsigned char tmp[64];
     generate_random_bytes(64, tmp);
@@ -62,12 +63,32 @@ namespace crypto {
     sc_reduce32(&res);
   }
 
-  void crypto_ops::generate_keys(public_key &pub, secret_key &sec) {
+  /* 
+   * generate public and secret keys from a random 256-bit integer
+   * TODO: allow specifiying random value (for wallet recovery)
+   * 
+   */
+  secret_key crypto_ops::generate_keys(public_key &pub, secret_key &sec, const secret_key& recovery_key, bool recover) {
     lock_guard<mutex> lock(random_lock);
     ge_p3 point;
-    random_scalar(sec);
+
+    secret_key rng;
+
+    if (recover)
+    {
+      rng = recovery_key;
+    }
+    else
+    {
+      random_scalar(rng);
+    }
+    sec = rng;
+    sc_reduce32(&sec);  // reduce in case second round of keys (sendkeys)
+
     ge_scalarmult_base(&point, &sec);
     ge_p3_tobytes(&pub, &point);
+
+    return rng;
   }
 
   bool crypto_ops::check_key(const public_key &key) {