Bech32(m) Encoding for Arbitrary Buffers

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Bech32 is a Bitcoin address format specified in [BIP 173][bip-173] and [BIP 350][bip-350].
Among its advantages are: better adaptability to QR codes and in voice conversations,
and improved error detection. This library generalizes Bech32 and its modified version
(Bech32m) to encode any reasonably short byte buffers.

Usage

$3

``typescript
declare function encode(
prefix: string,
data: Uint8Array,
encoding: 'bech32' | 'bech32m' = 'bech32'
): string;
`

Encodes binary data with the specified human-readable prefix into a Bech32(m) string.
The case is preserved: if the prefix is uppercase, then the output will be uppercase
as well; otherwise, the output will be lowercase (including the case when the prefix does
not contain any letters).

#### Arguments

- prefix: string
Human-readable prefix to hint what kind of data Bech32 encodes. Must contain
ASCII chars in the range 33-126
- data: Uint8Array
Binary data to encode
- encoding: bech32 or bech32m
Specifies whether to use the original Bech32 encoding from [BIP 173][bip-173]
or the modified encoding from [BIP 350][bip-350]; they differ
in how a checksum is computed. If omitted, the original encoding is used.

#### Return value

String containing:

1. prefix
2. '1' separator char
3. data encoded with the variant of base32 encoding used by Bech32, and
4. 6-char checksum calculated based on prefix and data

#### Example

`javascript
const bech32 = require('bech32-buffer');
const data = new Uint8Array(20);
bech32.encode('test', data);
// 'test1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqql6aptf'
`

$3

`typescript
declare function decode(message: string): {
prefix: string,
encoding: 'bech32' | 'bech32m',
data: Uint8Array
};
`

Extracts human-readable prefix and binary data from the Bech32-encoded string.

#### Arguments

- data: string
String to decode

#### Return value

An object with the following fields:

- prefix: string
Human-readable prefix
- encoding: bech32 or bech32m
Encoding variant inferred from the checksum.
- data: Uint8Array
Binary data encoded into the input string

Decoding may fail for a variety of reasons (e.g., invalid checksum, or invalid
chars in the input). In this case, decode() throws an exception
with a descriptive message.

#### Example

`javascript
const bech32 = require('bech32-buffer');
const data = 'lost1qsyq7yqh9gk0szs5';
bech32.decode(data);
// {
// prefix: 'lost',
// encoding: 'bech32',
// data: Uint8Array([ 4, 8, 15, 16, 23, 42 ])
// }
`

$3

`typescript
declare class BitcoinAddress {
prefix: 'bc' | 'tb';
scriptVersion: number;
data: Uint8Array;

static decode(message: string): BitcoinAddress;
constructor(prefix: 'bc' | 'tb', scriptVersion: number, data: Uint8Array);
encode(): string;
type(): void | 'p2wsh' | 'p2wpkh';
}
`

Provides basic functionality to work with Bech32 encoding of Bitcoin addresses.
Addresses can be decoded from strings and encoded into strings.
It is also possible to check the type of an address. P2WSH and P2WPKH address
types are defined per [BIP 141]. Encoding constraints are defined per [BIP 173][bip-173]
and [BIP 350][bip-350].

#### Example

`javascript
const { BitcoinAddress } = require('bech32-buffer');
const address = BitcoinAddress.decode('BC1QW508D6QEJXTDG4Y5R3ZARVARY0C5XW7KV8F3T4');
// address.prefix === 'bc'
// address.scriptVersion === 0
// address.data.length === 20
// address.type() === 'p2wpkh'
`

Use in Browsers

Use dist/bech32-buffer.min.js from the package distribution
or your favorite browserifier. In the first case,
the library will be available as a bech32 global variable:

`html



`

Check out the web demo to see how
bech32-buffer works in browser. It is also available in the examples
directory of the package.

Acknowledgements

[BIP 173][bip-173] is authored by Pieter Wuille and Greg Maxwell and is licensed
under the 2-clause BSD license.
[BIP 350][bip-350] is authored by Pieter Wuille and is licensed
under the 2-clause BSD license.

There are at least 2 existing implementations of Bech32 for JavaScript:

- [The reference implementation][ref] by Pieter Wuille
- [Another implementation][bech32] available as the [bech32` package][bech32-pkg]

Both implementations are Bitcoin-specific, and the reference implementation
is also not in the Npm / yarn package manager.

License

bech32-buffer is available under Apache-2.0 license.

[bip-173]: https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
[bip-350]: https://github.com/bitcoin/bips/blob/master/bip-0350.mediawiki
[ref]: https://github.com/sipa/bech32/tree/master/ref/javascript
[bech32]: https://github.com/bitcoinjs/bech32
[bech32-pkg]: https://www.npmjs.com/package/bech32
[BIP 141]: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki