Zcash shielded transactions

[krnak]

Orchard shielded transactions for Trezor T.

work in progress . you can use this PR for tracking my activity

Links

ZFND grant
documentation
milestone M.1 report
milestone M.2 report

Orchard addresses and keys

• orchard addresses
• unified addresses
• viewing keys export
• layouts
• ZIP-32 support
  Connectivity:
• trezorlib.zcash module
• trezorctl zcash commands
• Connect support
  Tests:
• unit tests
• tests on real device
• reviewed
• typing

Orchard transactions

• v5 transaction format
• signing workflow
• orchard inputs and outputs
• ZIP-244 (txid and sighash) implementation
• layouts
• graphically distinguish transparent and orchard outputs
• mixed transactions (transparent + orchard)
  Connectivity:
• python bridge to orchard crate (pyorchard) e.i. the prover is callable from python
• trezorlib.zcash module (raw version)
• trezorctl zcash commands
• Connect support
  Tests:
• unit tests
• tests on real device
• typing
• reviewed

Zcash crates

• librustzcash Add #![no_std] support for zcash_note_encryption zcash/librustzcash#450
• librustzcash Add #![no_std] support for f4jumble. zcash/librustzcash#446
• pasta_curves Support no-std builds zcash/pasta_curves#4
• reddsa Add no-std support ZcashFoundation/reddsa#11
• orchard Add support for no-std builds zcash/orchard#309
• orchard Add Note serialization zcash/orchard#297
• orchard Orchard proving API for hardware wallets zcash/orchard#287
• orchard Support externally computed signatures zcash/orchard#299

Firmware team

• reserve more memory for Zcash app
• integrate Sinsemilla table
• check Rust allocator correctness
• implementation review

Documentation

• implementation documentation (need to be updated)
• M.1 report
• M.2 report
• M.3 report

[krnak]

replacing this by #2472