e2e.dll - End-to-End Encryption for mIRC

Encrypted messaging for IRC channels and private queries using modern cryptography.

Algorithms

• Identity (signature): Ed25519
• Key exchange: X25519 (Diffie-Hellman)
• Encryption: XChaCha20-Poly1305 (AEAD)
• Base64: URL-safe, no padding (JSON-friendly)
• Key persistence: optional (DPAPI or password-encrypted store)

Build

Prerequisites

• Visual Studio 2026 (v145 toolset)
• libsodium 1.0.20 (already in libsodium/)

Build command

MSBuild e2e.vcxproj /p:Configuration=Release /p:Platform=Win32

Or simply:

build.bat

Important: mIRC is 32-bit only, so you must build Win32.

Auto-copy

copy_to_mirc.bat copies e2e.dll and e2e.mrc into C:\mIRC\.

mIRC Usage

Load script

/load -rs C:\mIRC\e2e.mrc

DM encryption flow

1. Share or request a DM key:

   /sharekey <nick>
   /requestkey <nick>
   

2. When you receive !enc-offer, accept or reject:

   /enc-accept <nick>
   /enc-reject <nick>
   

3. Send encrypted DM:

   /encmsg <nick> <message>
   

4. Optional auto-encrypt for a DM:

   /dmenc-on <nick>
   /dmenc-off <nick>
   

Quick encrypted send

New: Use /e2e <message> to send encrypted messages in any channel or query window.

/e2e This message will be encrypted
/e2e help

Behavior:

• In channel: Sends encrypted message using channel key (if available)
• In query: Sends encrypted DM using shared key (if available)
• No key: Shows helpful error with instructions on how to get a key
• Never sends plaintext: If no key exists, message is NOT sent
• Help: /e2e help displays all available E2E commands

Examples:

# In a channel window:
/e2e Secret meeting at 3pm

# In a query window:
/e2e Your password is hunter2

# Show all E2E commands:
/e2e help

# If no key exists, you'll see:
[E2E] No channel key for #secret
[E2E] To get a channel key:
[E2E]   1. Generate: /chankey generate
[E2E]   2. Request from user: /chankey request <nick>

Key persistence (optional)

You can persist keys securely using DPAPI or a password-encrypted store.

/e2e-persist off
/e2e-persist dpapi
/e2e-persist password
/e2e-setpass <password>
/e2e-save
/e2e-load

• DPAPI: automatic per-Windows-user encryption, no password needed.
• Password: requires /e2e-setpass each session to load/save.
• Keys are stored in C:\mIRC\e2e_store.hsh (encrypted).

Channel encryption flow

1. Generate a channel key (from inside the channel):

   /chankey generate
   

2. Share the key (DM) or request it:

   /chankey share <nick>
   /chankey request <nick>
   

   Outside a channel:

   /chankey share <#chan> <nick>
   /chankey request <#chan> <nick>
   

3. Send encrypted channel message:

   /chankey send <message>
   

4. Optional auto-encrypt for a channel:

   /chanenc-on [#chan]
   /chanenc-off [#chan]
   

Right-click menus

• Channel window -> E2E Encryption:
  • Share/Request DM Key
  • Generate/Share/Request Channel Key
  • Send Encrypted Message
  • Enable/Disable Auto Encrypt
  • Storage options (persistence mode, set password, save/load)
• Query window -> E2E Encryption:
  • Share/Request DM Key
  • Send Encrypted Message
  • Enable/Disable DM Auto Encrypt
  • Storage options (persistence mode, set password, save/load)
• Nick list (right-click on user in channel) -> E2E Encryption:
  • DM Key Management:
    • Share DM Key
    • Request DM Key
    • Send Encrypted DM
    • Enable/Disable DM Auto-Encrypt
  • Channel Key Management:
    • Share Channel Key
    • Request Channel Key
• User list (right-click on user) -> E2E Encryption:
  • DM Key Management:
    • Share DM Key
    • Request DM Key
    • Send Encrypted DM
    • Enable/Disable DM Auto-Encrypt
  • Channel Key Management:
    • Share Channel Key
    • Request Channel Key

Protocol

DM key offer

!enc-offer {"v":1,"idPub":"...","encPub":"...","sig":"..."}

• sig is a signature over encPub using Ed25519.

DM encrypted message

!enc-msg {"v":1,"from":"<encPub>","nonce":"...","cipher":"..."}

Channel key share (DM only)

!chanenc-key {"v":1,"channel":"#chan","network":"NetworkName","key":"...","createdAt":123}

Channel encrypted message

!chanenc-msg {"v":1,"nonce":"...","cipher":"..."}

DLL Functions

Function	Input	Output
GenKeys	0	`idPub
CreateOffer	`idPub	encPub
DeriveSecret	`idPub	encPub
EncryptDM	`key	myEncPub
DecryptDM	`key	nonce
GenChanKey	0	key (base64)
EncryptChan	`key	plaintext`
DecryptChan	`key	nonce
StoreEncrypt	`mode	password
StoreDecrypt	`mode	password
Version	0	Version string

Security Notes

What is strong

• Authenticated encryption (AEAD)
• Signature verification (Ed25519)
• Random nonces per message
• libsodium (audited, widely used)

Known limitations

• No perfect forward secrecy (no ratcheting)
• Keys live in memory only (no persistence)
• Encrypted persistence is optional (DPAPI or password)
• Channel key is shared by all users in the channel
• No replay protection

Troubleshooting

Logs

The DLL and script write diagnostic lines to:

C:\mIRC\e2e.logs

This includes load/self-test results and any DLL error returns. Use this file when reporting crashes or unexpected errors.

DLL does not load

//echo -a $dll(e2e.dll, Version, 0)

If it returns empty:

• Ensure e2e.dll is in C:\mIRC\
• Ensure Win32 build
• Reload: /dll -u e2e.dll then /load -rs e2e.mrc

Encryption does not work

• Confirm you exchanged DM keys (offer + accept)
• Confirm the channel key exists (/chankey generate or received via !chanenc-key)
• For auto-encrypt, verify it is enabled

Files

e2e.c           - Main DLL (test functions)
e2e_keyex.c     - Key exchange and crypto functions
e2e.def         - Export list
e2e.mrc         - mIRC script
e2e.vcxproj     - Visual Studio project
libsodium/      - Crypto library

License

Open source for educational use. Uses libsodium (ISC license).

Disclaimer: Experimental code, use at your own risk.