Block

Block format and order when signing a block, transmitting it between nodes and how it is stored in the database:

Name	Signing	Transmission	Database (type)	Description
prefix	✓	✗	✗	variable length. A unique prefix to ensure a block of another Validana instance is not valid in this instance.
total_length	✗	✓	✗	4 bytes little endian unsigned int. Indicates the length of what is to follow. This because a block has variable length.
version	✓	✓	✓ (smallint)	1 byte unsigned int indicating the version, currently only version 1 exists.
block_id	✓	✓	✓ (bitint)	8 bytes little endian unsigned int. Indicates the id of this block.
previous_block_hash	✓	✓	✓ (bytea)	32 bytes. Indicated the previous block hash.
processed_ts	✓	✓	✓ (bigint)	8 bytes little endian unsigned int. At what time this block was processed.
transactions	✓	✓	✓ (bytea)	variable length. A list of transaction in this block (in their transmission format.)
signature	✗	✓	✓ (bytea)	64 bytes, the ec signature of the block, 32 bytes r followed by 32 bytes s.

Block hash/Signing:

The block hash is created using double sha256 of the prefix, version, block_id, previous_block_hash, processed_ts and transactions of the block (concatenated in that order). This is then signed using the ECDSA Algorithm using the secp256k1 curve.

Transmitting:

When a block is transmitted the first 4 bytes indicate the total length of the remainder, which consists of the version, block_id, previous_block_hash, processed_ts, transactions and signature (concatenated in that order). No public key is transmitted as it will always be the same.