Some wallet refactorings

[supermassive]

Resolves brave/brave-browser#43451

Submitter Checklist:

• I confirm that no security/privacy review is needed and no other type of reviews are needed, or that I have requested them
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally:
  • npm run test -- brave_browser_tests, npm run test -- brave_unit_tests wiki
  • npm run presubmit wiki, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

[github-actions]

[puLL-Merge] - brave/brave-core@27325

Here's my review of the PR:

Description

This PR refactors Bitcoin-related code in Brave Wallet to improve code organization and security. The main changes include:

1. Moving BIP39 mnemonic functionality into its own module
2. Improving cryptographic hashing operations
3. Cleaning up error handling and removing redundant logging
4. Fixing potential security issues around buffer handling and signature verification
5. Improving type safety for cryptographic operations

Security Hotspots

1. SignCompact method in HDKey now enforces type safety for message and signature sizes through fixed-size spans, reducing risk of buffer overflow
2. F4 jumble implementation validates lengths and uses safe buffer operations
3. Secure hash operations now use size-specific types to prevent misuse

Changes

Changes

By filename:

components/brave_wallet/browser/bip39.{cc,h}:

• Added new module for BIP39 mnemonic functionality
• Implements mnemonic generation, validation and seed derivation

components/brave_wallet/browser/eth_transaction.{cc,h}:

• Fixed message signing to properly handle chain IDs
• Improved byte buffer safety

components/brave_wallet/browser/internal/hd_key.{cc,h}:

• Added type safety for cryptographic operations
• Fixed potential buffer overflows in signing methods

components/brave_wallet/common/hash_utils.{cc,h}:

• Centralized cryptographic hashing operations
• Added Blake2b implementation with proper validation
• Improved buffer handling for hash operations

sequenceDiagram
    participant Wallet
    participant BIP39
    participant HDKey 
    participant HashUtils

    Wallet->>BIP39: GenerateMnemonic()
    BIP39->>HashUtils: ComputeHash()
    HashUtils-->>BIP39: hash
    BIP39-->>Wallet: mnemonic

    Wallet->>BIP39: MnemonicToSeed()
    BIP39->>HashUtils: PBKDF2()
    HashUtils-->>BIP39: seed
    BIP39-->>Wallet: seed

    Wallet->>HDKey: SignMessage()
    HDKey->>HashUtils: Blake2b/Keccak
    HashUtils-->>HDKey: hash
    HDKey-->>Wallet: signature

Loading

[cypt4]

Could this be reused in the ZCashSerializer too?

[supermassive]

will do!

[cypt4]

Are there plans to get rid of IsValid methods and use expected\optionl instead?

[supermassive]

That's something I wanted to do but would be too much for this PR

[cypt4]

++