Block Types¶

XE has eight block types. Every block shares a set of common fields; each type adds its own type-specific fields.

Common fields¶

All blocks carry these fields:

Field	Type	Description
`Type`	string	Block type identifier: `send`, `receive`, `claim`, `lease`, `lease_accept`, `lease_settle`, `multisig_open`, `multisig_update`
`Account`	string	Hex-encoded ed25519 public key of the account that owns this block (64 hex chars)
`Previous`	string	Hash of the previous block on this account's chain; `"0"` for the first block
`Balance`	uint64	Account balance for this asset after this block
`Timestamp`	int64	Unix nanoseconds when the block was created
`Asset`	string	Asset identifier: `"XE"` or `"XUSD"`
`Representative`	string	Hex public key of this account's voting delegate (empty for no delegation)
`Hash`	string	SHA-256 hash of the canonical binary encoding (64 hex chars)
`Signature`	string	Ed25519 signature over the hash bytes (128 hex chars)
`PoWNonce`	uint64	Anti-spam proof-of-work nonce (excluded from hash computation)
`Signatures`	array	Multisig signatures array (replaces `Signature` for multisig accounts)
`Keyset`	object	Multisig keyset for `multisig_open` and `multisig_update` blocks

PoW nonce exclusion

The PoWNonce is computed after signing. It is excluded from Hash computation so the signature remains valid regardless of the nonce value. The PoW is validated separately by checking that blake2b(nonce || hashBytes) >= difficulty.

Send (`send`)¶

Debits the sender's balance and creates a pending send for the recipient.

Type-specific fields¶

Field	Type	Description
`Destination`	string	Hex public key of the recipient account
`Amount`	uint64	Number of tokens to send

Validation rules¶

Amount must be > 0.
Sender must have sufficient balance: previousBalance - Amount = Balance.
Destination must be a valid 32-byte hex-encoded public key.
Asset must be "XE" or "XUSD".

Side effects¶

On successful validation, a PendingSend record is created:

PendingSend{
    SendHash:    block.Hash,
    Source:      block.Account,
    Destination: block.Destination,
    Amount:      block.Amount,
    Asset:       block.Asset,
}

This pending send persists until the recipient creates a matching receive block.

Binary encoding¶

Type byte: 0x01. Tail: destination(32) + amount(8). Total canonical size: 162 bytes (90 header + 40 tail + 32 representative).

Receive (`receive`)¶

Credits the recipient's balance from a pending send.

Type-specific fields¶

Field	Type	Description
`Source`	string	Hash of the send block being received

Validation rules¶

Source must reference an existing pending send where Destination matches this block's Account.
Balance must equal previousBalance + pendingSend.Amount.
Asset must match the pending send's asset.

Side effects¶

The pending send referenced by Source is deleted. The recipient's balance increases by the send amount.

Binary encoding¶

Type byte: 0x02. Tail: source(32). Total canonical size: 154 bytes (90 header + 32 tail + 32 representative).

Claim (`claim`)¶

Mints 100 XUSD via the testnet faucet.

Type-specific fields¶

None. Claim blocks have no type-specific fields.

Validation rules¶

Balance must equal previousBalance + 100 (FaucetClaimAmount).
Asset must be "XUSD" (XE claims are rejected).
Rate limited: one claim per account per 24 hours.

Side effects¶

The account's XUSD balance increases by 100.

Testnet faucet

The faucet is testnet-only and rate limited to one claim per account per 24 hours.

Binary encoding¶

Type byte: 0x03. No tail. Total canonical size: 122 bytes (90 header + 32 representative).

Lease (`lease`)¶

Debits XUSD from the consumer to request a compute lease. This is the consumer's side of a lease transaction.

Type-specific fields¶

Field	Type	Description
`Destination`	string	Hex public key of the provider account
`Amount`	uint64	Total XUSD cost of the lease
`VCPUs`	uint64	Number of virtual CPUs requested
`MemoryMB`	uint64	Memory in megabytes
`DiskGB`	uint64	Disk in gigabytes
`Duration`	uint64	Lease duration in seconds

Validation rules¶

Asset must be "XUSD".
Amount must match the LeaseCost() formula (see Cost Model).
Sender must have sufficient XUSD balance: previousBalance - Amount = Balance.
Duration must be between 60 seconds and 31,536,000 seconds (365 days).
VCPUs, MemoryMB, and DiskGB must each be > 0.

Side effects¶

Creates a pending send (like a regular send) with the XUSD amount directed at the provider. The lease is not active until the provider creates a lease_accept block.

Binary encoding¶

Type byte: 0x04. Tail: destination(32) + amount(8) + vcpus(8) + memory_mb(8) + disk_gb(8) + duration(8) + access_pub_key(32). Total canonical size: 226 bytes (90 header + 104 tail + 32 representative).

Lease Accept (`lease_accept`)¶

The provider accepts a lease, staking XUSD as collateral. This activates the lease.

Type-specific fields¶

Field	Type	Description
`Source`	string	Hash of the consumer's lease block
`Amount`	uint64	XUSD stake amount (`cost / 5`)

Validation rules¶

Asset must be "XUSD".
Source must reference a valid, unaccepted lease block.
Amount must equal leaseCost / 5 (the stake divisor is 5).
Provider must have sufficient XUSD balance: previousBalance - Amount = Balance.
Requires timekeeper attestations if the state chain has sys.timekeepers configured.

Side effects¶

A Lease record is created tracking the consumer, provider, resources, cost, stake, and start time. The provider's XUSD is locked as stake.

Attestations¶

Lease accept blocks carry Attestations -- signed timestamps from trusted timekeeper nodes. These are not included in the block hash (they are attached after signing). Validation checks that the required number of attestations are present and their signatures are valid.

type TimekeeperAttestation struct {
    PublicKey string // hex ed25519 pubkey of timekeeper
    Timestamp int64  // unix nanos attested
    Signature string // hex ed25519 sig over sha256(leaseHashBytes || timestampBytes)
}

Binary encoding¶

Type byte: 0x05. Tail: source(32) + amount(8). Total canonical size: 162 bytes (90 header + 40 tail + 32 representative).

Lease Settle (`lease_settle`)¶

Settles an expired lease and emits XE as a reward to the provider.

Type-specific fields¶

Field	Type	Description
`Source`	string	Hash of the original lease block
`Amount`	uint64	XE emission reward

Validation rules¶

Asset must be "XE".
Source must reference an active (non-settled) lease.
The lease must have expired (current time > start time + duration).
Amount must match the emission formula based on the lease cost.
Requires timekeeper attestations if configured.

Side effects¶

The lease is marked as settled.
The provider's XUSD stake is returned (added back to their XUSD balance).
XE is emitted to the provider's account (Balance = previousXEBalance + Amount).

XE emission

Lease settlement is the mechanism by which new XE enters circulation. Providers earn XE proportional to the compute they deliver, creating a link between real-world utility and token emission.

Binary encoding¶

Type byte: 0x06. Tail: source(32) + amount(8). Total canonical size: 162 bytes (90 header + 40 tail + 32 representative).

Multisig Open (`multisig_open`)¶

Opens a new multisig account with a hash-derived address.

Type-specific fields¶

Field	Type	Description
`Keyset`	object	`{keys: [pubkey1, pubkey2, ...], threshold: N}`
`Signatures`	array	`[{public_key, signature}, ...]` — must have `threshold` valid signatures

Validation rules¶

account must equal sha256(canonical(keyset)) — the address is derived from the keyset.
keyset.threshold >= 1 and <= len(keys), no duplicate keys.
Block must have threshold valid signatures from keyset members.
Account must not already exist.
Balance must be 0.

Binary encoding¶

Type byte: 0x08. Tail: canonical_keyset(threshold_u32_be + num_keys_u32_be + sorted_keys_32_each). Canonical size varies with key count.

Multisig Update (`multisig_update`)¶

Rotates the keyset on an existing multisig account.

Type-specific fields¶

Field	Type	Description
`Keyset`	object	New keyset `{keys: [...], threshold: N}`
`Signatures`	array	Must have `threshold` valid signatures from the current (old) keyset

Validation rules¶

Account must be an existing multisig account.
Signed by the current keyset's threshold.
Balance must be unchanged.
The account address does NOT change (derived from original keyset).

Binary encoding¶

Type byte: 0x09. Same tail format as multisig_open.

Summary table¶

Type	Byte	Asset	Debits	Credits	Creates pending	Canonical size
`send`	`0x01`	XE or XUSD	sender	--	yes	162 bytes
`receive`	`0x02`	XE or XUSD	--	recipient	consumes pending	154 bytes
`claim`	`0x03`	XUSD	--	self (+100)	--	122 bytes
`lease`	`0x04`	XUSD	consumer	--	yes	226 bytes
`lease_accept`	`0x05`	XUSD	provider (stake)	--	creates Lease record	162 bytes
`lease_settle`	`0x06`	XE	--	provider (emission)	settles Lease record	162 bytes
`multisig_open`	`0x08`	XE or XUSD	--	--	registers keyset	varies
`multisig_update`	`0x09`	XE or XUSD	--	--	rotates keyset	varies

Block lifecycle¶

  Creator                   Network                     Recipient
  ───────                   ───────                     ─────────
  1. Build block fields
  2. MarshalBlockCanonical()
  3. SHA-256 → Hash
  4. ed25519.Sign(hash) → Signature
  5. ComputePoW(hash) → PoWNonce
  6. Broadcast via gossip ──────►
                            7. VerifyBlock (hash + sig)
                            8. ValidatePoW (nonce)
                            9. Ledger validation
                           10. Add to account chain
                           11. Rebroadcast ─────────────►
                                                        12. (for sends) appears as PendingSend
                                                        13. (recipient creates receive block)

Block Types¶

Common fields¶

Send (send)¶

Type-specific fields¶

Validation rules¶

Side effects¶

Binary encoding¶

Receive (receive)¶

Type-specific fields¶

Validation rules¶

Side effects¶

Binary encoding¶

Claim (claim)¶

Type-specific fields¶

Validation rules¶

Side effects¶

Binary encoding¶

Lease (lease)¶

Type-specific fields¶

Validation rules¶

Side effects¶

Binary encoding¶

Lease Accept (lease_accept)¶

Type-specific fields¶

Validation rules¶

Side effects¶

Attestations¶

Binary encoding¶

Lease Settle (lease_settle)¶

Type-specific fields¶

Validation rules¶

Side effects¶

Binary encoding¶

Multisig Open (multisig_open)¶

Type-specific fields¶

Validation rules¶

Binary encoding¶

Multisig Update (multisig_update)¶

Type-specific fields¶

Validation rules¶

Binary encoding¶

Summary table¶

Block lifecycle¶

Send (`send`)¶

Receive (`receive`)¶

Claim (`claim`)¶

Lease (`lease`)¶

Lease Accept (`lease_accept`)¶

Lease Settle (`lease_settle`)¶

Multisig Open (`multisig_open`)¶

Multisig Update (`multisig_update`)¶