/* eslint no-bitwise: ["error", {"allow": ["<<", ">>", "^", "&", "&="]}] */
import base32 from 'base32.js';
import { verifyChecksum } from './util/checksum';
const versionBytes = {
ed25519PublicKey: 6 << 3, // G (when encoded in base32)
ed25519SecretSeed: 18 << 3, // S
med25519PublicKey: 12 << 3, // M
preAuthTx: 19 << 3, // T
sha256Hash: 23 << 3, // X
signedPayload: 15 << 3, // P
contract: 2 << 3 // C
};
const strkeyTypes = {
G: 'ed25519PublicKey',
S: 'ed25519SecretSeed',
M: 'med25519PublicKey',
T: 'preAuthTx',
X: 'sha256Hash',
P: 'signedPayload',
C: 'contract'
};
/**
* StrKey is a helper class that allows encoding and decoding Stellar keys
* to/from strings, i.e. between their binary (Buffer, xdr.PublicKey, etc.) and
* string (i.e. "GABCD...", etc.) representations.
*/
export class StrKey {
/**
* Encodes `data` to strkey ed25519 public key.
*
* @param {Buffer} data raw data to encode
* @returns {string} "G..." representation of the key
*/
static encodeEd25519PublicKey(data) {
return encodeCheck('ed25519PublicKey', data);
}
/**
* Decodes strkey ed25519 public key to raw data.
*
* If the parameter is a muxed account key ("M..."), this will only encode it
* as a basic Ed25519 key (as if in "G..." format).
*
* @param {string} data "G..." (or "M...") key representation to decode
* @returns {Buffer} raw key
*/
static decodeEd25519PublicKey(data) {
return decodeCheck('ed25519PublicKey', data);
}
/**
* Returns true if the given Stellar public key is a valid ed25519 public key.
* @param {string} publicKey public key to check
* @returns {boolean}
*/
static isValidEd25519PublicKey(publicKey) {
return isValid('ed25519PublicKey', publicKey);
}
/**
* Encodes data to strkey ed25519 seed.
* @param {Buffer} data data to encode
* @returns {string}
*/
static encodeEd25519SecretSeed(data) {
return encodeCheck('ed25519SecretSeed', data);
}
/**
* Decodes strkey ed25519 seed to raw data.
* @param {string} address data to decode
* @returns {Buffer}
*/
static decodeEd25519SecretSeed(address) {
return decodeCheck('ed25519SecretSeed', address);
}
/**
* Returns true if the given Stellar secret key is a valid ed25519 secret seed.
* @param {string} seed seed to check
* @returns {boolean}
*/
static isValidEd25519SecretSeed(seed) {
return isValid('ed25519SecretSeed', seed);
}
/**
* Encodes data to strkey med25519 public key.
* @param {Buffer} data data to encode
* @returns {string}
*/
static encodeMed25519PublicKey(data) {
return encodeCheck('med25519PublicKey', data);
}
/**
* Decodes strkey med25519 public key to raw data.
* @param {string} address data to decode
* @returns {Buffer}
*/
static decodeMed25519PublicKey(address) {
return decodeCheck('med25519PublicKey', address);
}
/**
* Returns true if the given Stellar public key is a valid med25519 public key.
* @param {string} publicKey public key to check
* @returns {boolean}
*/
static isValidMed25519PublicKey(publicKey) {
return isValid('med25519PublicKey', publicKey);
}
/**
* Encodes data to strkey preAuthTx.
* @param {Buffer} data data to encode
* @returns {string}
*/
static encodePreAuthTx(data) {
return encodeCheck('preAuthTx', data);
}
/**
* Decodes strkey PreAuthTx to raw data.
* @param {string} address data to decode
* @returns {Buffer}
*/
static decodePreAuthTx(address) {
return decodeCheck('preAuthTx', address);
}
/**
* Encodes data to strkey sha256 hash.
* @param {Buffer} data data to encode
* @returns {string}
*/
static encodeSha256Hash(data) {
return encodeCheck('sha256Hash', data);
}
/**
* Decodes strkey sha256 hash to raw data.
* @param {string} address data to decode
* @returns {Buffer}
*/
static decodeSha256Hash(address) {
return decodeCheck('sha256Hash', address);
}
/**
* Encodes raw data to strkey signed payload (P...).
* @param {Buffer} data data to encode
* @returns {string}
*/
static encodeSignedPayload(data) {
return encodeCheck('signedPayload', data);
}
/**
* Decodes strkey signed payload (P...) to raw data.
* @param {string} address address to decode
* @returns {Buffer}
*/
static decodeSignedPayload(address) {
return decodeCheck('signedPayload', address);
}
/**
* Checks validity of alleged signed payload (P...) strkey address.
* @param {string} address signer key to check
* @returns {boolean}
*/
static isValidSignedPayload(address) {
return isValid('signedPayload', address);
}
/**
* Encodes raw data to strkey contract (C...).
* @param {Buffer} data data to encode
* @returns {string}
*/
static encodeContract(data) {
return encodeCheck('contract', data);
}
/**
* Decodes strkey contract (C...) to raw data.
* @param {string} address address to decode
* @returns {Buffer}
*/
static decodeContract(address) {
return decodeCheck('contract', address);
}
/**
* Checks validity of alleged contract (C...) strkey address.
* @param {string} address signer key to check
* @returns {boolean}
*/
static isValidContract(address) {
return isValid('contract', address);
}
static getVersionByteForPrefix(address) {
return strkeyTypes[address[0]];
}
}
/**
* Sanity-checks whether or not a strkey *appears* valid.
*
* @param {string} versionByteName the type of strkey to expect in `encoded`
* @param {string} encoded the strkey to validate
*
* @return {Boolean} whether or not the `encoded` strkey appears valid for the
* `versionByteName` strkey type (see `versionBytes`, above).
*
* @note This isn't a *definitive* check of validity, but rather a best-effort
* check based on (a) input length, (b) whether or not it can be decoded,
* and (c) output length.
*/
function isValid(versionByteName, encoded) {
if (typeof encoded !== 'string') {
return false;
}
// basic length checks on the strkey lengths
switch (versionByteName) {
case 'ed25519PublicKey': // falls through
case 'ed25519SecretSeed': // falls through
case 'preAuthTx': // falls through
case 'sha256Hash': // falls through
case 'contract':
if (encoded.length !== 56) {
return false;
}
break;
case 'med25519PublicKey':
if (encoded.length !== 69) {
return false;
}
break;
case 'signedPayload':
if (encoded.length < 56 || encoded.length > 165) {
return false;
}
break;
default:
return false;
}
let decoded = '';
try {
decoded = decodeCheck(versionByteName, encoded);
} catch (err) {
return false;
}
// basic length checks on the resulting buffer sizes
switch (versionByteName) {
case 'ed25519PublicKey': // falls through
case 'ed25519SecretSeed': // falls through
case 'preAuthTx': // falls through
case 'sha256Hash': // falls through
case 'contract':
return decoded.length === 32;
case 'med25519PublicKey':
return decoded.length === 40; // +8 bytes for the ID
case 'signedPayload':
return (
// 32 for the signer, +4 for the payload size, then either +4 for the
// min or +64 for the max payload
decoded.length >= 32 + 4 + 4 && decoded.length <= 32 + 4 + 64
);
default:
return false;
}
}
export function decodeCheck(versionByteName, encoded) {
if (typeof encoded !== 'string') {
throw new TypeError('encoded argument must be of type String');
}
const decoded = base32.decode(encoded);
const versionByte = decoded[0];
const payload = decoded.slice(0, -2);
const data = payload.slice(1);
const checksum = decoded.slice(-2);
if (encoded !== base32.encode(decoded)) {
throw new Error('invalid encoded string');
}
const expectedVersion = versionBytes[versionByteName];
if (expectedVersion === undefined) {
throw new Error(
`${versionByteName} is not a valid version byte name. ` +
`Expected one of ${Object.keys(versionBytes).join(', ')}`
);
}
if (versionByte !== expectedVersion) {
throw new Error(
`invalid version byte. expected ${expectedVersion}, got ${versionByte}`
);
}
const expectedChecksum = calculateChecksum(payload);
if (!verifyChecksum(expectedChecksum, checksum)) {
throw new Error(`invalid checksum`);
}
return Buffer.from(data);
}
export function encodeCheck(versionByteName, data) {
if (data === null || data === undefined) {
throw new Error('cannot encode null data');
}
const versionByte = versionBytes[versionByteName];
if (versionByte === undefined) {
throw new Error(
`${versionByteName} is not a valid version byte name. ` +
`Expected one of ${Object.keys(versionBytes).join(', ')}`
);
}
data = Buffer.from(data);
const versionBuffer = Buffer.from([versionByte]);
const payload = Buffer.concat([versionBuffer, data]);
const checksum = Buffer.from(calculateChecksum(payload));
const unencoded = Buffer.concat([payload, checksum]);
return base32.encode(unencoded);
}
// Computes the CRC16-XModem checksum of `payload` in little-endian order
function calculateChecksum(payload) {
const crcTable = [
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108,
0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210,
0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 0x9339, 0x8318, 0xb37b,
0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401,
0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee,
0xf5cf, 0xc5ac, 0xd58d, 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6,
0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d,
0xc7bc, 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 0x5af5,
0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc,
0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 0x6ca6, 0x7c87, 0x4ce4,
0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd,
0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13,
0x2e32, 0x1e51, 0x0e70, 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a,
0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e,
0xe16f, 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 0x02b1,
0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb,
0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 0x34e2, 0x24c3, 0x14a0,
0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8,
0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657,
0x7676, 0x4615, 0x5634, 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9,
0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882,
0x28a3, 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 0xfd2e,
0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07,
0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 0xef1f, 0xff3e, 0xcf5d,
0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74,
0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
];
let crc16 = 0x0;
for (let i = 0; i < payload.length; i += 1) {
const byte = payload[i];
const lookupIndex = (crc16 >> 8) ^ byte;
crc16 = (crc16 << 8) ^ crcTable[lookupIndex];
crc16 &= 0xffff;
}
const checksum = new Uint8Array(2);
checksum[0] = crc16 & 0xff;
checksum[1] = (crc16 >> 8) & 0xff;
return checksum;
}
Source