New update · Desktop beta 0.9.5

Speak freely.
Leave no echo.

Banshee is a privacy-first messenger built natively for Windows. End-to-end encrypted conversations, transparent device keys, and a relay architecture designed to know as little about you as possible.

↓ Download for WindowsRead the architecture
Windows 10/11 x64Windows installerNo account required
BANSHEE / DESKTOP
Mara K.● E2EE · safety number verified
SESSION ROTATED · 12:38
The release bundle is reproducible now. Same hash on both machines.12:40
Perfect. Send the manifest over the secure channel and I’ll countersign it.12:41 · delivered
Already there. Expiring in 24 hours.12:42
Message Mara…SEND ↗
X25519 + Ed25519Device identity and key agreement
AES-256-GCMAuthenticated content encryption
SQLCipher local vaultEncrypted data at rest
Zero ad trackersNo ads, pixels, or data resale
01 / Security model

Privacy is the architecture, not a toggle.

Every Banshee conversation is encrypted on your device before it touches the network. Relay nodes route opaque envelopes; message bodies, attachments, contact names, and group titles remain client-side secrets.

K1X3DH

Asynchronous key setup

Pre-key bundles allow secure sessions to begin while a contact is offline, with signed one-time keys preventing silent substitution.

↻RATCHET

Forward secrecy

A symmetric-key ratchet advances after every message. Compromising one state does not expose the full conversation history.

#60-DIGIT

Human-verifiable keys

Compare safety numbers in person, scan a QR code, or verify a key fingerprint through a separate trusted channel.

DBLOCAL

Encrypted local vault

Messages, thumbnails, and indices live in a SQLCipher database protected by a device-bound key stored through Windows DPAPI.

∅MIN-DATA

Metadata minimization

Random service identifiers replace phone numbers. Sealed-sender envelopes reduce the identity data visible to relays.

24TTL

Controlled retention

Per-chat expiry from 30 seconds to four weeks. Clients propagate tombstones and delete decrypted attachment caches.

02 / Under the hood

A narrow protocol surface.
Clear trust boundaries.

01
Native Windows client

WinUI 3 shell, isolated crypto service, hardware-backed secret storage when TPM 2.0 is available.

02
Opaque relay layer

Stateless WebSocket relays accept padded encrypted envelopes and short-lived delivery tokens.

03
Attachment object store

Client-side encrypted blobs use independent random keys; relay storage only sees ciphertext and expiry.

04
Key transparency log

Append-only device-key proofs make unexpected identity changes visible to clients. Beta rollout in progress.

ENVELOPE / CBORSPEC DRAFT 0.9
// relay-visible transport envelope
{
  version:    3,
  route_token: bytes[32],
  expires_at:  unix_ms,
  padding:     bucket(1024),
  ciphertext:  aead_blob
}

// client-decrypted message frame
header = HKDF(chain_key, message_no)
body   = AES_256_GCM.open(
  message_key, nonce, associated_data
)

// plaintext never crosses process boundary
zeroize(message_key)
ratchet.advance()
03 / Technical profile

Specific by design.

The beta protocol is versioned independently from the client. Cryptographic primitives are composed from maintained libraries; Banshee does not invent its own cipher.

Desktop beta 0.9.5

The downloadable package is a local interface preview for evaluating the Windows experience. Network messaging and production cryptography are not included in this preview build.

CHANNEL: PRIVATE BETA
UPDATED: AUGUST 18, 2026
LICENSE: PREVIEW TERMS

Supported OS
Windows 10 22H2 / 11
Target architecture
x86-64 · ARM64 planned
Transport
TLS 1.3 · WebSocket
Message encoding
Canonical CBOR
Local database
SQLite + SQLCipher
Secret storage
Windows DPAPI / TPM
Telemetry
Off by default
Independent audit
Scheduled before v1.0

Hear less noise.
Keep more privacy.

Try the native Windows interface preview today. The standalone desktop app launches locally without requiring an account.

↓ Download for Windows
EXE · WINDOWS X64