web3p / rlp

0.4.0 2026-09-23 19:59 UTC

Requires

• php: ^7.1 | ^8.0
• ext-mbstring: *

Requires (Dev)

• phpunit/phpunit: ~7|~8.0

MIT

• sc0Vu

Published on Packagist.org on 2026-09-23 20:01 UTC

README

Recursive Length Prefix Encoding in PHP.

Install

Set minimum stability to dev

composer require web3p/rlp

Usage

RLP encode:

use Web3p\RLP\RLP;

$rlp = new RLP;
// c483646f67
$encoded = $rlp->encode(['dog']);

// 83646f67
$encoded = $rlp->encode('dog');

RLP decode:

use Web3p\RLP\RLP;
use Web3p\RLP\Types\Str;

$rlp = new RLP;
$encoded = $rlp->encode(['dog']);

// accept hex string with or without 0x prefix
$decoded = $rlp->decode('0x' . $encoded);

// show 646f67
echo $decoded[0];

// show dog
echo hex2bin($decoded[0]);

// or you can
echo Str::decodeHex($decoded[0]);

API

Web3p\RLP\RLP

encode

Returns recursive length prefix encoding of given inputs.

encode(mixed $inputs)

Mixed inputs - string, integer, null, or (nested) array of them.

• Strings starting with 0x are encoded as hex bytes, byte for byte (leading zero bytes are kept). Strip leading zeros yourself for integer quantities, e.g. 0x00cb9d should be passed as 0xcb9d.
• Other strings are encoded as their raw bytes, numeric strings included ('1024' is encoded as the text 1024).
• Integers must be non-negative and not greater than PHP_INT_MAX; pass larger values as hex strings.
• null is encoded as an empty string, arrays are encoded as lists.

Throws InvalidArgumentException for invalid hex strings, negative or fractional numbers and unsupported types.

Note: output is not 0x prefixed.

Example

• Encode array of string.

use Web3p\RLP\RLP;

$rlp = new RLP;
$encoded = $rlp->encode(['web3p', 'ethereum', 'solidity']);

decode

Returns recursive length prefix decoding of given data: a hex string for a string item, or a (nested) array for a list.

decode(string $input)

String input - recursive length prefix encoded hex string, with or without 0x prefix.

Throws InvalidArgumentException if the input is not an even-length hex string, and RuntimeException if it is not valid canonical RLP (truncated data, trailing data or non-canonical lengths).

Note: output is not 0x prefixed.

Example

• Decode recursive length prefix encoded string.

use Web3p\RLP\RLP;
use Web3p\RLP\Types\Str;

$rlp = new RLP;
$encoded = $rlp->encode(['web3p', 'ethereum', 'solidity']);
$decoded = $rlp->decode('0x' . $encoded);

// echo web3p
echo hex2bin($decoded[0]);

// echo ethereum
echo hex2bin($decoded[1]);

// echo solidity
echo hex2bin($decoded[2]);

// or you can
echo Str::decodeHex($decoded[0]);
echo Str::decodeHex($decoded[1]);
echo Str::decodeHex($decoded[2]);

License

MIT