Whats the data format (or is it compatible) for "bmt multihash 0xd6 Binary Merkle Tree Hash" to hash binary forest pairs that define a function that returns byte[] id of another object (id of an id generator then its id)?

[benrayfield]

How would I give the context in the id to say what its hashing?

Something like... QmmultihashId...sdfsdf:bmt:occamsfuncerV1:contextSpecificId4234234 but that seems too many names in an id and theres binary form.

It is only a forest of pairs and leaf is all 0s (undecided on how many 0s), of calls of a universal lambda function which would for example derive a preprocessing of small literal bitstrings to quote them else use a securehash and may have bit masks etc... Since I dont want to deal with the never ending complexity of updating software when new stuff is added, I just want to use multihash to (less efficiently) name every possible binary forest (that generates a function) and let the functions do the rest, further optimizing, etc.

[Stebalien]

I believe bmt here refers to bmt-sha3. However, I'm not sure if there are any working implementations of this at the moment.

cc @acud? Should we rename this to bmt-sha3?

[benrayfield]

Theres already a data format for a merkle pointer. The multiformats header then whichever possible suffix that type allows. If theres no implementations of it, why not define the content to be hashed as a pair of multiformats objects?

Also I have use for a trinary forest. Maybe there should be a type for a list of n (varint) multiformats objects.
Are you sure theres no implementations? I read somewhere that ethereum uses a sha3 binary merkle forest but I'm not sure what else they put into the hash or what the leafs are.

[Stebalien]

If theres no implementations of it, why not define the content to be hashed as a pair of multiformats objects?
Are you sure theres no implementations? I read somewhere that ethereum uses a sha3 binary merkle forest but I'm not sure what else they put into the hash or what the leafs are.

The goal was to support an ETH2 use-case. I believe it was the sha3 binary merkle tree you're talking about. IIRC, they're hashing a pure binary tree where each node is exactly two hashes and the leaves are always 32 bytes (or 64 bytes?). They wanted to use this format to better support zero-knowledge proofs (e.g., zkSNARKs) over subsets of the hashed data.

Also I have use for a trinary forest. Maybe there should be a type for a list of n (varint) multiformats objects.

We'd usually just assign a new codec per variant. What does the internal structure of your tree look like?