From 932e0c891dc247bd37db7a38c9e432335eceb863 Mon Sep 17 00:00:00 2001
From: Sebastian <sebasjm@gmail.com>
Date: Thu, 3 Mar 2022 10:58:15 -0300
Subject: bitcoin manual withdraw when exchange has btc currency

---
 packages/taler-util/package.json   |  1 +
 packages/taler-util/src/bitcoin.ts | 63 ++++++++++++++++++++++++++++++++++++++
 packages/taler-util/src/index.ts   |  1 +
 3 files changed, 65 insertions(+)
 create mode 100644 packages/taler-util/src/bitcoin.ts

(limited to 'packages/taler-util')

diff --git a/packages/taler-util/package.json b/packages/taler-util/package.json
index 6a46de897..b1edbaf83 100644
--- a/packages/taler-util/package.json
+++ b/packages/taler-util/package.json
@@ -40,6 +40,7 @@
     "typescript": "^4.5.5"
   },
   "dependencies": {
+    "bech32-buffer": "^0.2.0",
     "big-integer": "^1.6.51",
     "jed": "^1.1.1",
     "tslib": "^2.3.1"
diff --git a/packages/taler-util/src/bitcoin.ts b/packages/taler-util/src/bitcoin.ts
new file mode 100644
index 000000000..dd90f514e
--- /dev/null
+++ b/packages/taler-util/src/bitcoin.ts
@@ -0,0 +1,63 @@
+/*
+ This file is part of GNU Taler
+ (C) 2019 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import { AmountJson } from "."
+import { Amounts, } from "./amounts"
+import { getRandomBytes, decodeCrock, encodeCrock } from "./talerCrypto"
+import { encode as segwitEncode } from "bech32-buffer"
+/**
+ *
+ * @author sebasjm
+ */
+
+export interface SegwitAddrs {
+  segwitAddr1: string,
+  segwitAddr2: string,
+}
+
+function buf2hex(buffer: Uint8Array) { // buffer is an ArrayBuffer
+  return [...new Uint8Array(buffer)]
+    .map(x => x.toString(16).padStart(2, '0'))
+    .join('');
+}
+
+export function generateSegwitAddress(reservePub: string): SegwitAddrs {
+  const pub = decodeCrock(reservePub)
+
+  const first_rnd = getRandomBytes(4)
+  const second_rnd = new Uint8Array(first_rnd.length)
+  second_rnd.set(first_rnd)
+
+  first_rnd[0] = first_rnd[0] & 0b0111_1111
+  second_rnd[0] = second_rnd[0] | 0b1000_0000
+
+  const first_part = new Uint8Array(first_rnd.length + pub.length / 2)
+  first_part.set(first_rnd, 0)
+  first_part.set(pub.subarray(0, 16), 4)
+  const second_part = new Uint8Array(first_rnd.length + pub.length / 2)
+  second_part.set(first_rnd, 0)
+  second_part.set(pub.subarray(16, 32), 4)
+
+  return {
+    segwitAddr1: segwitEncode("bc", first_part),
+    segwitAddr2: segwitEncode("bc", second_part),
+  }
+}
+
+// https://github.com/bitcoin/bitcoin/blob/master/src/policy/policy.cpp
+export function segwitMinAmount(): AmountJson {
+  return Amounts.parseOrThrow("BTC:0.00000294")
+}
\ No newline at end of file
diff --git a/packages/taler-util/src/index.ts b/packages/taler-util/src/index.ts
index c42e5e66a..0141be13b 100644
--- a/packages/taler-util/src/index.ts
+++ b/packages/taler-util/src/index.ts
@@ -23,6 +23,7 @@ export { fnutil } from "./fnutils.js";
 export * from "./kdf.js";
 export * from "./talerCrypto.js";
 export * from "./http-status-codes.js";
+export * from "./bitcoin.js";
 export {
   randomBytes,
   secretbox,
-- 
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