1 files changed, 131 insertions, 0 deletions
diff --git a/packages/taler-util/src/bech32.ts b/packages/taler-util/src/bech32.ts
new file mode 100644
index 000000000..e48e9ac3e
--- /dev/null
+++ b/packages/taler-util/src/bech32.ts
@@ -0,0 +1,131 @@
+// Copyright (c) 2017, 2021 Pieter Wuille
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+var CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
+var GENERATOR = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3];
+
+const encodings: any = {
+  BECH32: "bech32",
+  BECH32M: "bech32m",
+};
+
+export default {
+  decode: decode,
+  encode: encode,
+  encodings: encodings,
+};
+
+function getEncodingConst(enc: any) {
+  if (enc == encodings.BECH32) {
+    return 1;
+  } else if (enc == encodings.BECH32M) {
+    return 0x2bc830a3;
+  } else {
+    throw new Error("unknown encoding");
+  }
+}
+
+function polymod(values: any) {
+  var chk = 1;
+  for (var p = 0; p < values.length; ++p) {
+    var top = chk >> 25;
+    chk = ((chk & 0x1ffffff) << 5) ^ values[p];
+    for (var i = 0; i < 5; ++i) {
+      if ((top >> i) & 1) {
+        chk ^= GENERATOR[i];
+      }
+    }
+  }
+  return chk;
+}
+
+function hrpExpand(hrp: any) {
+  var ret = [];
+  var p;
+  for (p = 0; p < hrp.length; ++p) {
+    ret.push(hrp.charCodeAt(p) >> 5);
+  }
+  ret.push(0);
+  for (p = 0; p < hrp.length; ++p) {
+    ret.push(hrp.charCodeAt(p) & 31);
+  }
+  return ret;
+}
+
+function verifyChecksum(hrp: any, data: any, enc: any) {
+  return polymod(hrpExpand(hrp).concat(data)) === getEncodingConst(enc);
+}
+
+function createChecksum(hrp: any, data: any, enc: any) {
+  var values = hrpExpand(hrp).concat(data).concat([0, 0, 0, 0, 0, 0]);
+  var mod = polymod(values) ^ getEncodingConst(enc);
+  var ret = [];
+  for (var p = 0; p < 6; ++p) {
+    ret.push((mod >> (5 * (5 - p))) & 31);
+  }
+  return ret;
+}
+
+function encode(hrp: any, data: any, enc: any): string {
+  var combined = data.concat(createChecksum(hrp, data, enc));
+  var ret = hrp + "1";
+  for (var p = 0; p < combined.length; ++p) {
+    ret += CHARSET.charAt(combined[p]);
+  }
+  return ret;
+}
+
+function decode(bechString: any, enc: any) {
+  var p;
+  var has_lower = false;
+  var has_upper = false;
+  for (p = 0; p < bechString.length; ++p) {
+    if (bechString.charCodeAt(p) < 33 || bechString.charCodeAt(p) > 126) {
+      return null;
+    }
+    if (bechString.charCodeAt(p) >= 97 && bechString.charCodeAt(p) <= 122) {
+      has_lower = true;
+    }
+    if (bechString.charCodeAt(p) >= 65 && bechString.charCodeAt(p) <= 90) {
+      has_upper = true;
+    }
+  }
+  if (has_lower && has_upper) {
+    return null;
+  }
+  bechString = bechString.toLowerCase();
+  var pos = bechString.lastIndexOf("1");
+  if (pos < 1 || pos + 7 > bechString.length || bechString.length > 90) {
+    return null;
+  }
+  var hrp = bechString.substring(0, pos);
+  var data = [];
+  for (p = pos + 1; p < bechString.length; ++p) {
+    var d = CHARSET.indexOf(bechString.charAt(p));
+    if (d === -1) {
+      return null;
+    }
+    data.push(d);
+  }
+  if (!verifyChecksum(hrp, data, enc)) {
+    return null;
+  }
+  return { hrp: hrp, data: data.slice(0, data.length - 6) };
+}