Client and backend. This class is shared: the same code is compiled into your app and into your server, so everything on this page works in both.

public final class Bech32

Object
Bech32

Bech32 (BIP-173) and Bech32m (BIP-350) encoding, bit regrouping and the SegWit address helpers built on them.

Nested types

`class Bech32.Decoded`	The result of `decode(String)`.
`class Bech32.SegwitAddress`	The result of `decodeSegwitAddress(String, String)`.

Fields

`public static final int BECH32 = 1`	Checksum variant constant for original Bech32 (BIP-173).
`public static final int BECH32M = 2`	Checksum variant constant for Bech32m (BIP-350).

Methods

`public static` `String encode(String hrp, byte[] data, int variant)`	Encodes an HRP and 5-bit data into a Bech32 or Bech32m string.
`public static` `Bech32.Decoded decode(String str)`	Decodes and validates a Bech32 or Bech32m string.
`public static byte[] convertBits(byte[] data, int fromBits, int toBits, boolean pad)`	Regroups bits, for example 8-bit bytes to 5-bit values and back.
`public static` `String encodeSegwitAddress(String hrp, int witnessVersion, byte[] program)`	Encodes a SegWit address, using Bech32 for witness version 0 and Bech32m otherwise.
`public static` `Bech32.SegwitAddress decodeSegwitAddress(String hrp, String addr)`	Decodes and validates a SegWit address.

Inherited methods

From Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait, clone, finalize

Field details

BECH32

public static final int BECH32 = 1

Checksum variant constant for original Bech32 (BIP-173).

BECH32M

public static final int BECH32M = 2

Checksum variant constant for Bech32m (BIP-350).

Method details

encode

public static String encode(String hrp, byte[] data, int variant)

Encodes an HRP and 5-bit data into a Bech32 or Bech32m string.

Parameters

hrp String: the human readable part, 1 to 83 printable ASCII characters (33 to 126); uppercase is folded
data byte[]: values in the range 0 to 31
variant int: BECH32 or BECH32M

Returns

the lowercase encoded string

Throws

IllegalArgumentException: for an invalid HRP, data value, variant or total length over 90

decode

public static Bech32.Decoded decode(String str)

Decodes and validates a Bech32 or Bech32m string.

Parameters

str String: the encoded text

Returns

the HRP, data and checksum variant

Throws

IllegalArgumentException: for any violation of the BIP-173/BIP-350 rules

convertBits

public static byte[] convertBits(byte[] data, int fromBits, int toBits, boolean pad)

Regroups bits, for example 8-bit bytes to 5-bit values and back.

Parameters

data byte[]: input values, each fitting in fromBits bits
fromBits int: input group size, 1 to 8
toBits int: output group size, 1 to 8
pad boolean: whether leftover bits are zero padded (encoding) or must be zero and shorter than a group (decoding)

Returns

the regrouped values

Throws

IllegalArgumentException: for an out-of-range value or invalid padding

encodeSegwitAddress

public static String encodeSegwitAddress(String hrp, int witnessVersion, byte[] program)

Encodes a SegWit address, using Bech32 for witness version 0 and Bech32m otherwise.

Parameters

hrp String: the network prefix such as bc or tb
witnessVersion int: 0 to 16
program byte[]: the witness program, 2 to 40 bytes (20 or 32 for version 0)

Returns

the address

Throws

IllegalArgumentException: if the version or program length is invalid

decodeSegwitAddress

public static Bech32.SegwitAddress decodeSegwitAddress(String hrp, String addr)

Decodes and validates a SegWit address.

Parameters

hrp String: the expected network prefix, compared without regard to case
addr String: the address

Returns

the witness version and program

Throws

IllegalArgumentException: if the address is invalid or has another HRP