BancarioFaccia / Systems learning prototype
A Java prototype with length-prefixed binary messages, typed fields, Ed25519 signatures and bank-operation handlers.
Nominal authenticated envelope: 100 bytes plus body fields.
01 / My build
I implemented an 8-byte header, a 28-byte authentication block, typed body fields and a 64-byte Ed25519 signature. The server has registration, login, balance and transfer handlers and persists serialized state.
02 / Learning
The packet format carries a session nonce and sequence number, but the current server does not enforce replay checks. The development client also accepts all TLS certificates. These implementation gaps must be closed before the transport can be described as secure.
03 / Current limits
Canonical field ordering, account authorization, parser size bounds and persistence failures need further work. The reviewed repository has no structured build and no automated integration suite.
The packet sizes above describe the source format. A bandwidth comparison with JSON/HTTP would require a reproducible benchmark with equivalent payloads.
04 / Next steps
Enforce nonce and sequence checks, replace development TLS trust with certificate verification, add account-ownership checks and bound the parser. With a runnable client and adversarial tests, the protocol's behavior would be easier to demonstrate.