Support for Tree Tiger Hash and Merkle Hash Tree

[ivan386]

multiformats/multihash#55

Merkle Hash Tree multihash

<merkle-hash-tree-mc>-<len>-(<hash-tree-type>-<hash-mc>-<hash-len>-(<hash-value>)-[<hash-value>...])
<0x0400>-<len>-(<0x01>-<hash-mc>-<hash-len>-(<hash-value>)-[<hash-value>...])

0x0400 - Merkle Hash Tree (1024 decimal) multicodec value

0x01 - Hash Tree Type with this settings:

• Data segment size - 1024 bytes
• Data prefix - one byte with value 0 (0x00)
• Hash pair prefix - one byte with value 1 (0x01)
• Unpaired hashes move on next level unchanged.
• hashes in tree packed in breadth-first order from root to leafs.

0x02 - Hash Tree Type with this settings:

• Data segment size - 1024 bytes
• Data prefix - one byte with value 0 (0x00)
• Hash pair prefix - one byte with value 1 (0x01)
• Unpaired hashes move on next level unchanged.
• Level of hash tree
  1. level - 1 hash = root-hash
  2. level - 2 hashes
  3. level - 3-4 hashes
  4. level - 5-8 hashes
     and so on

Tiger multihash:

<tiger-mc>-<len>-<hash>
<0x7A>-<0x18>-<0x3293ac630c13f0245f92bbb1766e16167a4e58492dde73f3>

0x7A - Tiger-hash multicodec value

Tree Tiger multihash:

<merkle-hash-tree-mc>-<len>-(<hash-tree-type>-<tiger-mc><tiger-len>(<tiger-hash>)[<tiger-hash>...])

Tree sha2-256 multihash:

<merkle-hash-tree-mc>-<len>-(<hash-tree-type>-<sha2-256-mc>-<sha2-256-len>-(<sha2-256-hash>)[<sha2-256-hash>...])

Links:

Tree Hash EXchange format (THEX)
Tiger:
A Fast New Cryptographic Hash Function (Designed in 1995)
wikipedia: Tiger (cryptography)
wikipedia: Merkle tree#Tiger tree hash

License: MIT
Signed-off-by: Ivan [email protected]

[ivan386]

I write package that calc hash tree root: https://github.com/ivan386/go-hash-tree

[Artoria2e5]

To update to current format:

• The hash itself should be a multihash now.
• The tree serialization is ipld.

There is no serialization for the hash of the tree yet in your proposal. May I propose:

tiger-tree,                     multihash,      0x71c3,         draft,      Tiger Tree Hash with a block size of 1024 bytes (draft-jchapweske-thex-02)

71c3 because it looks like "tige".