Documentation Index
Fetch the complete documentation index at: https://docs.thru.org/llms.txt
Use this file to discover all available pages before exploring further.
Use this page when you need to carry, inspect, or size state proofs in C instruction payloads.
Public proof types
The C SDK exposes:
tsdk_state_proof_hdr_ttsdk_state_proof_ttsdk_state_proof_header_type(...)tsdk_state_proof_header_slot(...)tsdk_state_proof_footprint_from_header(...)
All of these live in tn_sdk_txn.h.
tsdk_state_proof_hdr_t contains:
| Field | Meaning |
|---|
type_slot | Top 2 bits encode proof type; lower 62 bits encode slot. |
path_bitset | Bitset used to derive sibling-hash count. |
| Helper | Meaning |
|---|
tsdk_state_proof_header_type(hdr) | Returns the proof type encoded in the top 2 bits. |
tsdk_state_proof_header_slot(hdr) | Returns the slot encoded in the lower 62 bits. |
tsdk_state_proof_footprint_from_header(hdr) | Returns the actual byte footprint of the full proof payload based on type and sibling-hash count. |
Proof body variants
The full tsdk_state_proof_t body covers three logical shapes:
| Variant | Layout |
|---|
| Existing | Sibling hashes only |
| Updating | Existing leaf hash plus sibling hashes |
| Creation | Existing leaf pubkey, existing leaf hash, then sibling hashes |
Most important sizing rule
Do not assume sizeof( tsdk_state_proof_t ) is the size of the proof payload you received.
Instead:
- read a
tsdk_state_proof_hdr_t
- call
tsdk_state_proof_footprint_from_header(...)
- validate the instruction buffer contains that many bytes
Minimal parsing pattern
if( instr_sz < sizeof( tsdk_state_proof_hdr_t ) ) tsdk_revert( 1UL );
tsdk_state_proof_hdr_t const * hdr =
(tsdk_state_proof_hdr_t const *)proof_bytes;
ulong proof_sz = tsdk_state_proof_footprint_from_header( hdr );
if( instr_sz < proof_offset + proof_sz ) tsdk_revert( 2UL );
tsdk_state_proof_t const * proof =
(tsdk_state_proof_t const *)proof_bytes;
Where proofs usually show up
| Use case | Related syscall or pattern |
|---|
| Account creation | tsys_account_create |
| Compression | tsys_account_compress |
| Decompression | tsys_account_decompress |
| Custom instruction payloads | Packed instruction header plus trailing proof bytes |
Notes
- Proofs are one of the most layout-sensitive parts of the SDK.
- Always validate the available byte count before casting proof tails.
- Use the header helper, not
sizeof, to reason about how many bytes the proof consumes.
