[jre]

Those are all very good points I didn't think about, thanks for these.

I'll fix the two bugs with verify_block and the possibility for a miner to inject invalid a output > input transaction.

I'll add a note for the 3 others.

[westurner]

For deterministic serialization (~canonicalization), you can use sort_keys=True or serialize OrderedDicts. For deseialization, you'd need object_pairs_hook=collections.OrderedDict.

Most current blockchains sign a binary representation with fixed length fields. In terms of JSON, JSON-LD is for graphs and it can be canonicalized. Blockcerts and Chainpoint are JSON-LD specs:

> Blockcerts uses the Verifiable Claims MerkleProof2017 signature format, which is based on Chainpoint 2.0.

https://github.com/blockchain-certificates/cert-verifier-js/...

[Cyph0n]

FYI, dicts are now ordered by default as of Python 3.6.

[cpburns2009]

That's an implementation detail, and shouldn't be relied upon. If you want an ordered dictionary, you should use collections.OrderedDict.

[westurner]

It's now the spec for 3.6+.

> #python news: @gvanrossum just pronounced that dicts are now guaranteed to retain insertion order. This is the end of a long journey.

https://twitter.com/raymondh/status/941709626545864704

More here: https://www.reddit.com/r/Python/comments/7jyluw/dict_knownor...

OrderedDicts are backwards-compatible and are guaranteed to maintain order after deletion.

[Cyph0n]

True, but if you need both key ordering and performance, dict is the better option.