WIP: wrote down starting point for hash-legacy

bippy-scratch.md

@@ -197,6 +197,20 @@ Native P2WPKH
 :: gives [wid=32 dat=0xc37a.f311.16d1.b27c.af68.aae9.e3ac.82f1.4779.2901.4d5b.9176.57d0.eb49.478c.b670]
 ```
 
+### Signing the above
+```
+=ecc secp256k1:secp:crypto
+=h dat:(~(sighash unsigned-tx:btc utx) 1)
+=priv 0x6.19c3.3502.5c7f.4012.e556.c2a5.8b25.06e3.0b85.11b5.3ade.95ea.316f.d8c0.3286.feb9
+(ecdsa-raw-sign:ecc h priv)
+
+::  desired r of sig:
+::  3609e17b84f6a7d30c80bfa610b5b4542f32a8a0d5447a12fb1366d7f01cc44a
+::
+::  desired s of sig:
+::  573a954c4518331561406f90300e8f3358f51928d43c212a8caed02de67eebee
+```
+
 ## cutting off the last 20 bytes (for bech32 address outputs):
 ```
 `@ux`(end 3 2 0x14.6655)

lib/btc.hoon

@@ -93,15 +93,14 @@
     =/  =input:tx  (snag input-index inputs.ut)
     ?:  =(1 witness-ver.input)
       (sighash-witness input)
-    (sighash-legacy input)
+    (sighash-legacy input-index)
   ::
   ++  sighash-witness
     |=  =input:tx  ^-  hash
     =/  prevouts=byts
       %-  concat-as-byts  (turn inputs.ut prevouts-buffer)
     =/  sequences=byts
-      %-  concat-as-byts
-      (turn inputs.ut sequence-buffer)
+      %-  concat-as-byts  (turn inputs.ut sequence-buffer)
     =/  outputs=byts
       %-  concat-as-byts  (turn outputs.ut outputs-buffer)
     ::  Hash inputs in order, as per BIP143 examples
@@ -139,7 +138,10 @@
     ==
   ::
   ++  sighash-legacy
-    |=  =input:tx  ^-  hash
+    |=  input-index=@  ^-  hash
+    ::  TODO: turn each input
+    ::  make the script be 0x0
+    ::  at the end, use snap to replace ONLY the one at input-index with the real script
    [0 0x0]
   --
 ::