Signal is a complete messenger: end-to-end encrypted by default, and it needs a phone number to register and both people to be on Signal. HushHush is not a messenger. It encrypts a message on your phone before you send it through an app you cannot leave, such as work Slack, WhatsApp or SMS, and two people pair in person by QR code with no number and no account. HushHush does not replace Signal. If you can move a conversation to Signal, do. HushHush is for the ones you cannot move.
What Signal does, in Signal's own terms
Signal is run by an independent nonprofit, and its home page states that it cannot read your messages or listen to your calls, and that nobody else can either. Every message and call is end-to-end encrypted with the Signal Protocol, which Signal publishes in full: the X3DH and PQXDH key agreements, the Double Ratchet that gives each message a fresh key, and post-quantum work such as the ML-KEM Braid. Its privacy policy adds that your message history is stored on your own devices. That is about as good as a messenger gets.
Two things are worth knowing. First, registration. Signal's privacy policy says you create an account by registering your phone number. Usernames, introduced in February 2024, hide that number from the people you talk to, but the post announcing them says a number is still needed to sign up. In September 2026 Signal began testing a paid sign-up without a number in its Android beta: a one-time fee of about three US dollars, and an account ID and key that cannot be recovered if lost. It is not on iPhone yet, and existing accounts cannot drop their number.
Second, metadata. Signal has done more here than almost anyone. Sealed sender, introduced in 2018, hides who sent a message from Signal's own service: the service has to know where to deliver a message, not who it came from. Signal also says it does not store a record of your contacts, social graph or conversation list, and that resistance to traffic correlation is still ongoing work. HushHush cannot claim that: a HushHush message travels through whatever app you paste it into, and that app sees everything about the exchange except the words.
| What | Signal | HushHush |
|---|---|---|
| The words you type, readable by the service | No. End-to-end encrypted | No. The carrying app sees ciphertext |
| Who you message, and when | Partly. Sealed sender hides the sender | Yes. The carrying app sees it |
| A phone number handed to the service | Yes, to register | None. There is no account at all |
| Both people must install the same app | Yes, Signal | Yes, HushHush, plus any app to carry it |
| Works inside Slack, WhatsApp, SMS or email | No. Signal messages stay in Signal | Yes. Paste anywhere |
| Voice and video calls | Yes, encrypted | No. Text only |
| Forward secrecy | Yes. Double Ratchet, every chat | On automatic one-to-one chats over Telegram, Matrix or email |
| Post-quantum protection | Yes. PQXDH key agreement | Optional Ultra Secure pairing, chosen in person |
When you need both
Use Signal for every conversation you can move there. It is free, it is pleasant to use, and the people who built it have spent years making the hard parts invisible. If the other person will install Signal, do that.
The conversations you cannot move are the reason HushHush exists. The colleague who only answers on Slack, where the admin can export the workspace. The client who insists on email. The relative who lives in WhatsApp and will not switch, but will install one small app and paste a block of text when it matters. In each case the carrying app is fixed, and the only thing you control is what goes into it. HushHush makes that a block of ciphertext.
Then there is the phone number: a source who will not give you one, a client you would rather not put in any directory. Signal's username setting helps, and its number-free sign-up is on its way on Android. HushHush simply has nothing to protect there: pairing is a QR code scanned in a room, and no record of it exists anywhere else.
How HushHush helps
HushHush encrypts the text on your phone before it goes into the app you have to use. That app carries only ciphertext, and the other person decrypts it in their HushHush. Both people need the app and one in-person pairing. No number, no account, no server of ours.
Pair once, in person
Open HushHush, add a contact, and scan the QR code on the other phone. No account, no phone number, no server.
Type it in HushHush
Write the message and tap send. It is encrypted on your phone and copied as ciphertext.
Paste it into Slack, WhatsApp or SMS
That app carries the ciphertext. Your contact pastes it into HushHush to read it. Or connect Telegram, Matrix or email inside HushHush and it is sent and decrypted automatically.
What HushHush does not do. It is not a messenger: no calls, no contact directory and no delivery service, because there is no server. It does not hide who you talk to or when; the carrying app still sees the ciphertext, its length and the time. Both people need HushHush. It protects text only. And it does not replace Signal.
Frequently asked questions
Does HushHush replace Signal?
Is Signal really private?
Does Signal need a phone number?
Can I use HushHush inside Signal?
Which is more secure, Signal or HushHush?
Encrypt it before the app sees it.
HushHush is on the App Store and Google Play. Pair in person, then send in any app.
Related
Sources
- Signal home page, Signal, accessed 7 October 2026.
- Signal Terms & Privacy Policy, Signal, accessed 7 October 2026.
- Technical information: Signal Protocol specifications, Signal, accessed 7 October 2026.
- Technology preview: Sealed sender for Signal, Signal blog, 29 October 2018, accessed 7 October 2026.
- Keep your phone number private with Signal usernames, Signal blog, 20 February 2024, accessed 7 October 2026.
- Beta feedback for the upcoming Android 8.28 release, Signal community forum (posted by Signal staff), 16 September 2026, accessed 7 October 2026.