Independent

srijaldutta.official+sime@gmail.com

This document specifies the SIME protocol, a decentralized, atomic protocol for inter-domain mail transmission and entity-to-entity communication. It defines packet types, headers, MX/SRV-based trust verification, TCP-based delivery, and SIME Extensions for attachments. All servers act as Domain Authorities (DA), and inter-domain transactions are governed by atomic protocol rules.

SIME (Srijal's Integrated Mail Extensions) is a decentralized protocol designed to provide reliable messaging between users in different Domain Authorities (DA). Each DA manages its own user authentication and registration rules. Atomic protocol enforcement ensures inter-domain transactions follow strict compatibility, reliability, and security rules. All SIME traffic is conducted over TCP to ensure reliable delivery.

DA (Domain Authority) - Server managing a domain and its users ID - Disposable session identifier (e.g., JWT) Transaction ID - Identifier assigned per transaction session TCP - Transmission Control Protocol (mandatory transport) MAIL Packet - Packet containing mail messages CONV Packet - Packet for general communication MX/SRV Record - DNS record or SRV record pointing to server endpoint for inter-domain verification

- Users authenticate with their DA and receive disposable IDs. - Communication is TCP-only to prevent packet loss. - Two primary packet types: CONV and MAIL. - Inter-domain transactions require MX/SRV verification to ensure messages reach the correct DA server. - Atomic rules enforce uniformity; non-compliant servers are rejected.

CONV Packets: Used for login and general communications:

START TRANSACTION CONV ]]>

MAIL Packets: Used for sending messages:

X-Mailed-Type-Render: ; RECIPIENT: user@domain PREPARE MESSAGE END TRANSACTION ]]>

- SENDER: Originating user (user@domain) - RECIPIENT: Destination user (user@domain) - X-Mailed-Type-Render: TXT | MD | HTML - Optional headers may be added via SIME Extensions

Users initiate login via CONV packet:

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Server responses:

ERROR AUTH ]]>

Disposable IDs are required for subsequent packets.

1. User logs in: CONV Packet → LOGIN → SUCCESS LOGIN : <ID> 2. User initiates transaction: CONV Packet → START TRANSACTION <ID> 3. Server validates ID: - Success → returns transaction acknowledgment - Failure → returns ERROR AUTH 4. User sends MAIL packet: - PREPARE HEADERS <transact_id> ... - PREPARE MESSAGE <transact_id> <content> 5. User ends transaction: END TRANSACTION <transact_id> 6. Server responds with SENT or appropriate error.

- No version negotiation; all inter-domain servers must implement the exact protocol. - Non-compliant servers are rejected. - Transactions must be atomic: either all steps succeed or fail.

- DA MX/SRV record must point to verified server endpoint. - Messages are sent only to verified MX/SRV endpoints. - Servers not listed or failing verification are rejected.

- ERROR AUTH : Invalid login/session - ERROR TRANS : Transaction initiation failure - ERROR HEADER : Invalid or missing headers - ERROR MXVER : Inter-domain MX/SRV verification failure - ERROR PACKET : Malformed packet - ERROR SEND : Message could not be delivered

- All packets use TCP for reliable delivery. - Authentication handled per DA; disposable IDs required. - TLS is recommended for inter-domain traffic. - Disposable IDs and transaction IDs mitigate replay attacks. - Inter-domain trust relies on MX/SRV verification; unverified endpoints are rejected. - Confidentiality and integrity of message content require TLS or optional message signing. - Reviewers should note that deployment must account for standard-compliant DNS/SRV usage instead of arbitrary IP:PORT MX records.

- Each DA must publish a SIME MX or SRV record specifying its server endpoint. - Inter-domain messages are routed only to verified endpoints. - Unverified endpoints are rejected.

- ATTACHMENT: <filename> - ENCODING: base64 | hex - Optional metadata headers supported - Attached in content as: <UNICODE UTF-8: 0xEF 0xBF 0xBF><hex|base64> <encoded attachment><UNICODE UTF-8: 0xEF 0xBF 0xBF>

| SUCCESS LOGIN | | START TRANSACTION | | |------------------>| TRANS_ID: 67890 | | PREPARE HEADERS | | |------------------>| PROCEED | | PREPARE MESSAGE | | |------------------>| PROCEED | | END TRANSACTION | | |------------------>| SENT | ]]>

Srijal Dutta Email: srijaldutta.official+sime@gmail.com