Ticket: WCN-284

This pull request introduces a comprehensive migration from synchronous encryption and decryption methods to their asynchronous counterparts throughout the codebase, with a focus on improving support for v2 encryption. The changes affect key management, wallet operations, transaction verification, and API routes, ensuring better scalability and compatibility with modern cryptographic practices. Additionally, new async verification utilities are introduced, and related tests and error messages are updated accordingly.

Migration to Async Encryption/Decryption:

• Replaced all usages of encrypt and decrypt with encryptAsync and decryptAsync in wallet logic (lightning.ts, selfCustodialLightning.ts), UTXO coin and transaction verification, and Express API handlers to support v2 encryption and improve non-blocking behavior. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]

Async Key Verification Utilities:

• Added verifyUserPublicKeyAsync to verifyKey.ts and updated transaction and coin verification logic to use the new async method, while preserving the synchronous version for backward compatibility. [1] [2] [3] [4] [5] [6] [7]

Refactoring and API Consistency:

• Refactored helper functions and type signatures to be async, including decryption helpers and key derivation logic in Express Lightning routes, to ensure consistency across all API endpoints. [1] [2] [3]

Test and Error Message Updates:

• Updated tests to use async stubs and improved error messages for decryption failures to reflect the new async flow and provide clearer diagnostics. [1] [2] [3] [4]

Backward Compatibility and Deprecation:

• Marked synchronous methods as deprecated where appropriate, and provided clear migration paths to async methods, especially in UTXO coin classes and key verification utilities. [1] [2]

These changes collectively modernize the cryptographic operations in the codebase, preparing it for future enhancements and improved security practices.