Block Structure in TON Blockchain

TON blocks are composed of a fixed‑size header and a variable‑size body. This design, combined with Merkle trees and the infinity‑sharding paradigm, enables scalable, verifiable storage across the network.

Overview#

TON employs a flexible block architecture that differs from traditional blockchains with a static size limit. The network is organized into three layers: the masterchain, which stores global metadata; workchains, which host specific protocols or applications; and shardchains, which process transactions in parallel.

Block Layout#

Each block contains a header, a body, and cryptographic proofs. The header holds essential metadata, while the body stores transactions and account state changes.

Header (Masterchain)

The header is a fixed‑size segment that includes:

A reference to the previous block (cryptographic hash)
The root hash of the block’s Merkle tree
Workchain ID indicating the shard to which the block belongs
The next slot number, defining when the next block should be produced

Additional fields may contain validator information, block size limits, and the protocol version.

Body (Shardchain)

The body is variable‑size and holds:

Transactions (cryptocurrency transfers, smart‑contract calls, etc.)
Account state updates resulting from those transactions

Separating the header from the body allows dynamic block sizes, letting the network handle fluctuating transaction volumes without sacrificing efficiency.

Merkle Tree for Data Integrity#

Blocks use a Merkle tree to ensure data integrity. Each transaction or data item is hashed, and these hashes are combined up the tree until a single root hash represents the entire block. Any alteration changes the root hash, making tampering evident.

Transaction Layout#

Every transaction comprises:

Header (logical time, account identifier)
Input data (sender information and original message)
Action data (smart‑contract execution details)
Output data (messages to other accounts or shards)

This structure provides clear traceability of each transaction’s lifecycle.

Sharding in TON#

Sharding divides the network into independent shards, each processing its own transactions. The infinity‑sharding paradigm dynamically creates shards based on demand, allowing the network to scale horizontally without congestion.

Workchains and Parallel Processing#

Workchains act as separate logical blockchains within TON. Each workchain contains its own shardchains, enabling concurrent transaction processing and higher overall throughput compared to a single‑chain design.

Smart Contracts and Block Structure#

Smart contracts are recorded within blocks, with execution results, state changes, and inter‑contract messages stored alongside regular transactions. This integration supports decentralized applications while preserving block integrity.

Security and Integrity#

TON relies on strong cryptographic primitives: hash functions secure data integrity, and digital signatures validate blocks and transactions. Consensus follows a Byzantine Fault Tolerant (BFT) algorithm, ensuring decentralized validation. Lightweight clients can operate by downloading only block headers, reducing resource requirements.

Advantages of TON Block Structure#

Scalability: Dynamic block sizes and infinity‑sharding allow the network to handle large transaction volumes.
Efficiency: Fixed‑size headers keep metadata compact, while variable bodies adapt to workload.
Security: Merkle trees and BFT consensus provide strong guarantees of data integrity and trustless validation.