Memo Chunks (v3)

The blob is split into 585-byte chunks, base64-encoded, and written to Solana memo transactions.

Chunk Format

FD:{hash8}:{index}:{base64data}

Field	Size	Description
FD:	3 chars	Protocol prefix
hash8	8 chars	First 8 hex chars of manifest SHA-256 (no sha256: prefix)
index	2+ chars	Zero-padded chunk index ("00", "01", ...)
base64data	~780 chars	Base64-encoded 585-byte raw chunk

Total per memo TX: ~795 bytes (within Solana's 1,232 byte limit)

Constants

MEMO_CHUNK_SIZE    = 600    (header + payload)
MEMO_PAYLOAD_SIZE  = 585    (raw bytes per chunk)
V3_HEADER_SIZE     = 15     (FD:{hash8}:{idx}:)
MEMO_PROGRAM_ID    = MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr

Chunk Count

chunk_count = ceil(blob_bytes / 585)

Example: a 5 MB file produces a ~5 MB blob (49B header + file), requiring ceil(5,242,929 / 585) = 8,963 memo transactions.

Pointer Memo

After all chunks are confirmed, a single pointer memo is sent. This is the index — anyone can find all chunks from the pointer alone.

FREEZEDRY:3:{hash}:{chunkCount}:{blobSize}:{chunkSize}:{flags}:{inscriber}:{lastSig}

Field	Description
hash	Full manifest hash (sha256:abcdef...)
chunkCount	Number of chunks inscribed
blobSize	Total blob size in bytes
chunkSize	585 (constant, for verification)
flags	Content type + encryption mode flags
inscriber	First 8 chars of inscriber's wallet address
lastSig	TX signature of the last chunk (for ordering/discovery)

Reconstruction (Hydration)

Three ways to reconstruct a file from chain:

1. From Signatures

Provide the JSON array of all chunk TX signatures. Fetch each TX, extract memo data, decode base64, reassemble in order.

2. From Pointer

Provide one pointer TX signature:

1. Fetch the pointer TX → parse FREEZEDRY:3: memo

2. Extract hash, chunk count, and inscriber wallet

3. Scan inscriber's TX history via getSignaturesForAddress

4. Match memos containing FD:{hash8}: prefix

5. Sort by chunk index → decode → reassemble

3. From NFT

Provide a Metaplex Core NFT mint address:

1. Call DAS getAsset → read inscriptionHash attribute

2. Find pointer memo in the inscription authority's TX history

3. Chain into pointer resolve (method 2 above)