Almost every app for moving files between your phone and computer says it’s encrypted. That can mean very different things. Some encrypt the connection between two devices; some encrypt files on their way to a server that can still read them; a few encrypt on your device with keys only your devices hold. This guide sorts the common options by what their own documentation says, checked on October 18, 2026.
Three questions separate them:
- Who holds the keys? End-to-end encryption means only your devices can decrypt what you send. Encryption “in transit” protects the trip, but a server in the middle may still be able to read it.
- Does it work across networks? Many encrypted tools only work on the same Wi-Fi or within a few feet.
- Does it reach a device that’s asleep or offline? Direct transfers need both devices on at once. Only a service that stores your content, encrypted, can deliver it later.
The options compared
| Tool | Encryption, per its own docs | Across networks | Reaches an offline device | Open source |
|---|---|---|---|---|
| Signal Note to Self | End-to-end | Yes | Yes | Yes |
| Proton Drive | End-to-end (cloud storage) | Yes | Yes, as stored files | Yes |
| fwd | End-to-end | Yes | Yes | No |
| Taildrop | Encrypted peer to peer (WireGuard) | Yes | Not stated | Client, yes |
| Blip | Says end-to-end (mTLS over TLS 1.3) | Yes | No | No |
| LocalSend | Says end-to-end (HTTPS between devices) | No | No | Yes |
| KDE Connect | TLS between devices | Only over a VPN | No | Yes |
| Syncthing | TLS between devices | Yes | No | Yes |
| AirDrop | TLS | No, nearby only | No | No |
| PairDrop | WebRTC, in transit | Yes | No | Yes |
| Telegram Saved Messages | Server-client, not end-to-end | Yes | Yes | Apps only |
End-to-end encrypted, even when the other device is off
Signal Note to Self
Signal’s Note to Self is a chat with yourself, and Signal says everything in it is end-to-end encrypted. You can use it to share messages and files with your linked devices.[1] Signal queues end-to-end encrypted messages on its servers for devices that are temporarily offline.[2] It’s open source and free. The catches: it needs a phone number, it’s built around your phone, and linked devices are unlinked if your phone doesn’t come online at least once every 30 days.[3]
Proton Drive
Proton Drive is end-to-end encrypted cloud storage: files and their names are encrypted on your device before they’re uploaded, so only you hold the keys.[4] Proton says all its apps are open source and independently audited.[5] It’s storage rather than sending: you upload on one device and open on the other, which works well for files and less well for a quick link or note.
fwd
I’m building fwd (pronounced “forward”) for this exact job: links, text and files between your own devices, end-to-end encrypted, including to a device that’s asleep. Each forward is encrypted on the device that sends it, waits on the server as ciphertext, and is decrypted when your other device comes back online. Page titles, file names and device names are encrypted too.
- Where it runs: a Chrome extension that also loads in other Chromium browsers, an app for Android 8.0 and later, and a menu bar app for macOS 14 and later. There is no iPhone, iPad or native Windows app.
- Limits: files up to 25 MB, 1 GB of storage and 5 devices on the free plan.
- What to know: the security page explains which keys exist, who holds them, how a new device joins and what the server can still see, such as your email address, which device sent a forward and its size. No independent audit is published yet, and the code isn’t public.
- Availability: a private beta; invitations go out to the waitlist in batches.
Encrypted device to device, while both are on
Taildrop
Taildrop, part of Tailscale, sends files over encrypted peer-to-peer connections, and only the sending and receiving devices can access them.[6] Tailscale says its connections are end-to-end encrypted with WireGuard.[7] It works between networks and sends only to your own devices. It needs Tailscale on every device, a failed transfer can be resumed for up to an hour, and Taildrop is still marked alpha.[6]
Blip
Blip says transfers are end-to-end encrypted with a mutually authenticated connection (mTLS over TLS 1.3), and that when a direct connection isn’t possible, data goes through its encrypted relay network.[8] It doesn’t describe how keys are created or held, and its co-founder has said it’s closed source and hasn’t had a third-party audit.[9] It’s excellent for large files between devices that are both online. I wrote more about it in Blip alternatives.
LocalSend
LocalSend describes its transfers as end-to-end encrypted.[10] Technically they’re HTTPS between the two devices, with a certificate generated on each device and no server in between.[11] It’s open source and needs no account, but only works on the same local network.
KDE Connect and Syncthing
KDE Connect encrypts traffic between devices with TLS and sends it directly over the local network, never through the internet; a VPN extends that to other networks.[12] Syncthing secures all device-to-device traffic with TLS, and when devices can’t connect directly, its relays only pass on the encrypted data.[13] Both are open source. Syncthing keeps folders in sync rather than sending one thing, and its official Android app has been discontinued.[14]
AirDrop and Quick Share
Apple encrypts AirDrop connections with TLS, directly between nearby devices without the internet.[15] Google’s Quick Share works between nearby devices too; its help page doesn’t say how those transfers are encrypted. When it sends to an iPhone or Mac by link instead, Google says the files are end-to-end encrypted and kept on its servers for 24 hours.[16]
PairDrop
PairDrop runs in the browser. WebRTC encrypts files in transit, but its own FAQ says you still have to trust the PairDrop server that sets up the connection.[17] Both browsers have to be open.
Not end-to-end for this job
Telegram’s Saved Messages is a cloud chat with yourself, and cloud chats use server-client encryption, not end-to-end. Telegram’s end-to-end Secret Chats are tied to one device, so they can’t move things between your devices.[18] Pushbullet’s documentation lists end-to-end encryption only for notification mirroring, universal copy and paste, and SMS; it doesn’t list pushes or files.[19]
Which should you use?
For big files on the same Wi-Fi, LocalSend is free and open source. For big files between networks, with both devices on, Taildrop or Blip. If you already live in Signal and only need the occasional file, Note to Self is end-to-end encrypted and reaches offline devices. If you send links, text and everyday files between a phone and a computer all day, and want them waiting when you get there, fwd is built for that; join the waitlist.
Related guides
- Blip alternatives for links, text and devices that are offline
- LocalSend alternatives for sharing beyond your Wi-Fi
- Pushbullet alternatives in 2026: what still works
- How to transfer files from Android to Mac in 2026
- KDE Connect alternatives: options beyond the same network
Sources
Checked on October 18, 2026.
- Note to Self. Signal Support.
- Terms of Service & Privacy Policy. Signal.
- Linked Devices. Signal Support.
- Proton Drive. Proton.
- Open source. Proton.
- Send files with Taildrop. Tailscale.
- Security. Tailscale.
- Security on Blip. Blip Studio, updated June 16, 2026.
- Verify Security Claims? r/blippers, reply from Blip’s co-founder.
- LocalSend: Share files to nearby devices. LocalSend.
- localsend/localsend. GitHub.
- KDE Connect privacy policy. KDE.
- Security principles. Syncthing documentation.
- syncthing/syncthing-android. GitHub.
- AirDrop security. Apple Platform Security.
- Share files & content with Quick Share. Android Help.
- PairDrop FAQ. GitHub.
- Telegram FAQ. Telegram.
- Pushbullet API documentation. Pushbullet.