Accounts

An "Account" in the XAG Ledger represents a holder of XAG and a sender of transactions. The core elements of an account are:

  • An identifying address, such as rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn

  • An XAG balance. Some of this XAG is set aside for the Reserve.

  • A sequence number, which helps make sure any transactions this account sends are applied in the correct order and only once each. To execute a transaction, the transaction's sequence number and its sender's sequence number must match. Then, as part of applying the transaction, the account's sequence number increases by 1. (See also: Basic Data Types: Account Sequence.)
  • A history of transactions that affected this account and its balances.
  • One or more ways to authorize transactions, possibly including:
    • A master key pair intrinsic to the account. (This can be disabled but not changed.)
    • A "regular" key pair that can be rotated.
    • A signer list for multi-signing. (Stored separately from the account's core data.)

In the ledger's data tree, an account's core data is stored in the AccountRoot ledger object type. An account can also be the owner (or partial owner) of several other types of data.

Tip: An "Account" in the XAG Ledger is somewhere between the financial usage (like "bank account") and the computing usage (like "UNIX account"). Non-XAG currencies and assets aren't stored in an XAG Ledger Account itself; each such asset is stored in an accounting relationship called a "Trust Line" that connects two parties.

Creating Accounts

There is not a dedicated "create account" transaction. The Payment transaction automatically creates a new account if the payment sends XAG equal to or greater than the account reserve to a mathematically-valid address that does not already have an account. This is called funding an account, and creates an AccountRoot object in the ledger. No other transaction can create an account.

Caution: Funding an account does not give you any special privileges over that account. Whoever has the secret key corresponding to the account's address has full control over the account and all XAG it contains. For some addresses, it's possible that no one has the secret key, in which case the account is a black hole and the XAG is lost forever.

The typical way to get an account in the XAG Ledger is as follows:

  1. Generate a key pair from a strong source of randomness and calculate the address of that key pair. (For example, you can use the wallet_propose method to do this.)

  2. Have someone who already has an account in the XAG Ledger send XAG to the address you generated.

    • For example, you can purchase XAG in a private exchange, then withdraw XAG from the exchange to the address you specified.

      Caution: The first time you receive XAG at your own XAG Ledger address, you must pay the account reserve (currently 20 XAG), which locks up that amount of XAG indefinitely. In contrast, private exchanges usually hold all their customers' XAG in a few shared XAG Ledger accounts, so customers don't have to pay the reserve for individual accounts at the exchange. Before withdrawing, consider whether having your own account directly on the XAG Ledger is worth the price.

Addresses

Accounts in the XAG Ledger are identified by an address in the XAG Ledger's base58 format. The address is derived from the account's master public key , which is in turn derived from a secret key. An address is represented as a string in JSON and has the following characteristics:

  • Between 25 and 35 characters in length

  • Starts with the character r

    Note: The XAG community has proposed (and developed a codec to support) a new X-address format that exchanges and wallets could use instead of destination tags . These "packed" addresses start with an X instead of an r. For more information, see the XAGL 𝗫-address format site.

  • Uses alphanumeric characters, excluding the number "0" capital letter "O", capital letter "I", and lowercase letter "l"

  • Case-sensitive
  • Includes a 4-byte checksum so that the probability of generating a valid address from random characters is approximately 1 in 2^32

For more information, see Accounts and base58 Encodings.

Any valid address can become an account in the XAG Ledger by being funded. You can also use an address that has not been funded to represent a regular key or a member of a signer list. Only a funded account can be the sender of a transaction.

Creating a valid address is a strictly mathematical task starting with a key pair. You can generate a key pair and calculate its address entirely offline without communicating to the XAG Ledger or any other party. The conversion from a public key to an address involves a one-way hash function, so it is possible to confirm that a public key matches an address but it is impossible to derive the public key from the address alone. (This is part of the reason why signed transactions include the public key and the address of the sender.)

For more technical details of how to calculate an XAG Ledger address, see Address Encoding.

Special Addresses

Some addresses have special meaning, or historical uses, in the XAG Ledger. In many cases, these are "black hole" addresses, meaning the address is not derived from a known secret key. Since it is effectively impossible to guess a secret key from only an address, any XAG possessed by black hole addresses is lost forever.

Address Name Meaning Black Hole?
rrrrrrrrrrrrrrrrrrrrrhoLvTp ACCOUNT_ZERO An address that is the XAG Ledger's base58 encoding of the value 0. In peer-to-peer communications, rippled uses this address as the issuer for XAG. Yes
rrrrrrrrrrrrrrrrrrrrBZbvji ACCOUNT_ONE An address that is the XAG Ledger's base58 encoding of the value 1. In the ledger, RippleState entries use this address as a placeholder for the issuer of a trust line balance. Yes
rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh The genesis account When rippled starts a new genesis ledger from scratch (for example, in stand-alone mode), this account holds all the XAG. This address is generated from the seed value "masterpassphrase" which is hard-coded . No
rrrrrrrrrrrrrrrrrNAMEtxvNvQ Ripple Name reservation black-hole In the past, Ripple asked users to send XAG to this account to reserve Ripple Names. Yes
rrrrrrrrrrrrrrrrrrrn5RM1rHd NaN Address Previous versions of ripple-lib generated this address when encoding the value NaN using the XAG Ledger's base58 string encoding format. Yes

Deletion of Accounts

The DeletableAccounts amendment (enabled 2020-05-08) made it possible to delete accounts.

To be deleted, an account must meet the following requirements:

  • The account's Sequence number plus 256 must be less than the current Ledger Index.
  • The account must not be linked to any of the following types of ledger objects (as a sender or receiver):
    • RippleState
  • The account must own fewer than 1000 objects in the ledger.

After an account has been deleted, it can be re-created in the ledger through the normal method of creating accounts. An account that has been deleted and re-created is no different than an account that has been created for the first time.

Unlike Bitcoin and many other cryptocurrencies, each new version of the XAG Ledger's public ledger chain contains the full state of the ledger, which increases in size with each new account. For that reason, you should not create new XAG Ledger accounts unless necessary. You can recover some of an account's 20 XAG reserve by deleting the account, but you must still destroy at least 5 XAG to do so.

Institutions who send and receive value on behalf of many users can use Source Tags and Destination Tags to distinguish payments from and to their customers while only using one (or a handful) of accounts in the XAG Ledger.

Transaction History

In the XAG Ledger, transaction history is tracked by a "thread" of transactions linked by a transaction's identifying hash and the ledger index. The AccountRoot ledger object has the identifying hash and ledger of the transaction that most recently modified it; the metadata of that transaction includes the previous state of the AccountRoot node, so it is possible to iterate through the history of a single account this way. This transaction history includes any transactions that modify the AccountRoot node directly, including:

  • Transactions sent by the account, because they modify the account's Sequence number. These transactions also modify the account's XAG balance because of the transaction cost.

The conceptual transaction history of an account also includes transactions that modified the account's owned objects and non-XAG balances. These objects are separate ledger objects, each with their own thread of transactions that affected them. If you have an account's full ledger history, you can follow it forward to find the ledger objects created or modified by it. A "complete" transaction history includes the history of objects owned by a transaction, such as:

  • RippleState objects (Trust Lines) connected to the account.
  • DirectoryNode objects, especially the owner directory tracking the account's owned objects.
  • Offer objects, representing the account's outstanding currency-exchange orders in the decentralized exchange
  • SignerList objects, representing lists of addresses that can authorize transactions for the account by multi-signing.

For more information on each of these objects, see the Ledger Format Reference.

Address Encoding

Tip: These technical details are only relevant for people building low-level library software for XAG Ledger compatibility!

[Source]

XAG Ledger addresses are encoded using base58 with the dictionary rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz. Since the XAG Ledger encodes several types of keys with base58, it prefixes the encoded data with a one-byte "type prefix" (also called a "version prefix") to distinguish them. The type prefix causes addresses to usually start with different letters in base58 format.

The following diagram shows the relationship between keys and addresses:

Master Public Key + Type Prefix β†’ Account ID + Checksum β†’ Address

The formula for calculating an XAG Ledger address from a public key is as follows. For the complete example code, see encode_address.js . For the process of deriving a public key from a passphrase or seed value, see Key Derivation.

  1. Import required algorithms: SHA-256, RIPEMD160, and base58. Set the dictionary for base58.

    'use strict';
const assert = require('assert');
const crypto = require('crypto');
const R_B58_DICT = 'rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz';
const base58 = require('base-x')(R_B58_DICT);

assert(crypto.getHashes().includes('sha256'));
assert(crypto.getHashes().includes('ripemd160'));

  2. Start with a 33-byte ECDSA secp256k1 public key, or a 32-byte Ed25519 public key. For Ed25519 keys, prefix the key with the byte 0xED.

    const pubkey_hex =
  'ED9434799226374926EDA3B54B1B461B4ABF7237962EAE18528FEA67595397FA32';
const pubkey = Buffer.from(pubkey_hex, 'hex');
assert(pubkey.length == 33);

  3. Calculate the RIPEMD160 hash of the SHA-256 hash of the public key. This value is the "Account ID".

    const pubkey_inner_hash = crypto.createHash('sha256').update(pubkey);
const pubkey_outer_hash = crypto.createHash('ripemd160');
pubkey_outer_hash.update(pubkey_inner_hash.digest());
const account_id = pubkey_outer_hash.digest();

  4. Calculate the SHA-256 hash of the SHA-256 hash of the Account ID; take the first 4 bytes. This value is the "checksum".

    const address_type_prefix = Buffer.from([0x00]);
const payload = Buffer.concat([address_type_prefix, account_id]);
const chksum_hash1 = crypto.createHash('sha256').update(payload).digest();
const chksum_hash2 = crypto.createHash('sha256').update(chksum_hash1).digest();
const checksum =  chksum_hash2.slice(0,4);

  5. Concatenate the payload and the checksum. Calculate the base58 value of the concatenated buffer. The result is the address.

    const dataToEncode = Buffer.concat([payload, checksum]);
const address = base58.encode(dataToEncode);
console.log(address);
// rDTXLQ7ZKZVKz33zJbHjgVShjsBnqMBhmN