A regular phone call is the least private call you can make. The Electronic Frontier Foundation says it plainly: “When you make a call from a landline or a mobile phone, your call is not end-to-end encrypted.” The phone company carries the call, and as the EFF notes, that lets governments or anyone else with power over the phone company record it. In December 2024 the US cybersecurity agency CISA urged “highly targeted” individuals, such as senior officials, to make consistent use of end-to-end encryption.
Calling apps promise better, and nearly all of them use the word “encrypted.” What you want to know is narrower. Is the call encrypted end to end? Does that cover group calls too? And what can the service still see while you talk? This guide goes through the popular apps one at a time.
The short answer
Signal, WhatsApp, FaceTime and Threema encrypt every call end to end, one-to-one and group. Telegram’s calls are end-to-end encrypted too, although its ordinary chats aren’t. LINE and Viber encrypt one-to-one calls end to end but not group calls. Session’s calls are end-to-end encrypted and still in beta. KakaoTalk and Zalo don’t say that their calls are end-to-end encrypted. Krypton Ø (Krypton zero), our own app, encrypts voice calls end to end between people who are already connected.
If all you need is a private call with someone, Signal is the simplest pick. If you also care who can tell that you called, or whether the other person sees your IP address, the details below matter more than the table.
“Encrypted” and “end-to-end encrypted” are different promises
Nearly every app encrypts a call on its way to the company’s servers. That keeps out someone on the same Wi-Fi network, but the company in the middle can still open the call. End-to-end encryption means the keys exist only on the phones taking part, so the servers that carry the call can’t listen to it.
LINE’s own encryption report shows the difference inside a single app. Its one-to-one calls are end-to-end encrypted. Then the report adds: “Group calls, group video calls, and Line meeting are only protected with transport-level encryption.” It’s the same app and the same word, “encrypted,” with two levels of protection behind it.
The table shows where each app stands today.
| App | One-to-one calls | Group calls | Phone number to sign up |
|---|---|---|---|
| Signal | End-to-end encrypted | End-to-end encrypted, up to 75 people | Yes (an Android beta adds sign-up without one) |
| End-to-end encrypted | End-to-end encrypted | Yes | |
| Telegram | End-to-end encrypted | End-to-end encrypted, up to 200 people | Yes |
| FaceTime | End-to-end encrypted | End-to-end encrypted, up to 33 people | A phone number or an Apple Account |
| Threema | End-to-end encrypted | End-to-end encrypted, up to 16 people | No |
| Session | End-to-end encrypted (beta, off by default) | Not available | No |
| LINE | End-to-end encrypted | Transport-level encryption only | In some countries |
| Viber | End-to-end encrypted | Not end-to-end encrypted | Yes |
| Krypton Ø | End-to-end encrypted, voice only | Not available | No |
Krypton Ø is our own app, so read that row knowing who wrote it.
Apps that encrypt every call end to end
Signal
Signal says its messages and calls can’t be accessed by Signal or anyone else “because they are always end-to-end encrypted, private, and secure.” There’s nothing to switch on and no kind of call that’s left out. Group calls hold up to 75 people.
Signal can connect a call directly between the two phones, which sounds better but shows each phone the other’s IP address. A setting called “Always relay calls” sends every call through Signal’s servers instead. It’s off by default, and the app warns that turning it on will reduce call quality.
Signal’s released apps still ask for a phone number at sign-up. A beta of the Android app adds Signal Login, which creates an account with no phone number in exchange for a small one-time purchase.
WhatsApp calls are end-to-end encrypted, one-to-one and group alike. Group calls are always relayed through WhatsApp’s servers, and they stay end-to-end encrypted on the way.
For one-to-one calls there’s an optional setting, “Protect IP address in calls,” under Settings, Privacy, Advanced. With it on, your calls are relayed through WhatsApp’s servers so the other person can’t see your IP address.
You need a mobile phone number to sign up.
FaceTime
Apple’s wording is short: “We designed FaceTime to use end-to-end encryption. We never store the content of FaceTime calls.” Group FaceTime supports up to 33 people at once, and those calls are end-to-end encrypted among the invited participants’ devices. FaceTime sets up a direct connection between devices when it can.
FaceTime is also a clear example of what end-to-end encryption leaves out. Apple says it “may record and store information about FaceTime calls, such as who was invited to a call, and your device’s network configurations, and store this information for up to 30 days.” Nobody at Apple can hear the call. A record that it happened is a separate matter.
You sign in with a phone number or an Apple Account.
Threema
Threema says that “just like Threema messages, voice calls and video calls are end-to-end encrypted.” Group calls are end-to-end encrypted as well and hold up to 16 people in the standard app.
Threema is careful with IP addresses. It connects a call directly when it can, but a call with a contact you haven’t verified is routed through Threema’s server, and an “Always relay calls” option does the same for every call. Group calls are “routed through a server, which obscures the IP address of the participants amongst one another.”
It needs no phone number. You get a Threema ID, and the app is a one-time purchase.
Krypton Ø
Krypton Ø is an invite-only, end-to-end encrypted social network, and calling is one part of it. Calls are voice only and one-to-one, between people who are already connected. Krypton Ø calls them Fam. The audio is encrypted on the two phones, and each phone signs the connection details with its own key, so a call that’s tampered with in the middle doesn’t connect.
Every call goes through a relay server, so the person you call doesn’t see your IP address. The relay sees both phones’ IP addresses but can’t open the audio. The ring is delivered encrypted, the server keeps no call records, and call history stays on each phone. Krypton Ø never asks for a phone number or an email.
Apps where it depends on the call
Telegram
Telegram’s ordinary chats aren’t end-to-end encrypted, but its calls are. In Telegram’s words: “You can make end-to-end encrypted Voice Calls and Video Calls, and you can turn any call into a Group Call with up to 200 participants.” End-to-end encrypted group calls arrived in April 2025, and people in a call can compare the four emoji on their screens to confirm that nobody is sitting in the middle.
The exception is older. Since 2021 Telegram has also had video chats that run inside groups and live streams for channels, and it doesn’t describe those as end-to-end encrypted.
On IP addresses, Telegram has a Peer-to-Peer setting under Settings, Privacy and Security, Calls. A Telegram spokesperson told TechCrunch in November 2023 that calls between contacts are peer-to-peer by default, while calls from people outside your contacts go through Telegram’s servers. Choosing Never sends every call through the servers, so the other side doesn’t get your IP address.
A Telegram account has to be connected to a mobile number.
LINE
LINE’s end-to-end encryption is called Letter Sealing, and it has been on by default in the main LINE apps since 2016. One-to-one voice and video calls are end-to-end encrypted with it. Group calls, group video calls and LINE meetings aren’t. They get transport-level encryption only, which protects them on the way to LINE’s servers but not from the servers themselves.
How you sign up depends on where you live. In Japan, Taiwan, Thailand, Hong Kong and South Korea, LINE verifies a phone number. Elsewhere you can sign up with an Apple or Google account.
Viber
Viber end-to-end encrypts one-to-one voice and video calls automatically. Its help pages also list what isn’t end-to-end encrypted, and that list includes group calls, voice and video, and Viber Out, its paid calling service.
One-to-one calls use a peer-to-peer connection to improve quality, which means the two phones exchange IP addresses. You can turn that off, and Viber warns that “it will reduce your call quality.”
Viber accounts are tied to a phone number.
Session
Session says its calls are end-to-end encrypted, but calling is a beta feature that’s turned off by default. It works between two people only, and only with someone already in your contacts. There are no group calls yet.
Session’s messages travel through an onion-routing network. Its calls don’t. They use a peer-to-peer connection, and Session warns that “your IP will be shared with your call partner as well as an STF operated STUN/TURN server.” Session needs no phone number or email.
Apps that don’t say
KakaoTalk
Kakao says the audio and video of its voice and video calls aren’t stored on Kakao’s servers. That’s a statement about storage, which isn’t the same thing as end-to-end encryption. We couldn’t find a current official document stating that KakaoTalk calls are end-to-end encrypted. Where Kakao does describe end-to-end encryption is its optional Secret Chat. Group calls hold up to 10 people, and sign-up needs a phone number.
Zalo
Zalo published an end-to-end encryption white paper in April 2022. Calls aren’t on its list of what’s covered, and we couldn’t find an official statement that Zalo calls are end-to-end encrypted. Sign-up needs a phone number.
None of this proves that a call on either app can be listened to. It means the company hasn’t said that it can’t, and with calls, that statement is the thing to look for.
What an end-to-end encrypted call still gives away
That the call happened. Encryption covers the audio, not the fact of the call. Apple’s 30-day record of who was invited to a FaceTime call is one example. At the other end, Signal says the only account information it can provide in response to a legal request is when the account was created and the date it last connected. It’s worth reading what each service says it keeps.
Your IP address. A direct connection between two phones sounds better, and it shows each phone the other’s IP address, which roughly gives away a city and an internet provider. Relaying the call through a server hides it from the other person, at some cost in quality. Signal, WhatsApp, Telegram, Viber and Threema each have a setting for this. Session’s beta calls share your IP address with the person you call.
The number behind the account. Signal, WhatsApp, Telegram and Viber accounts are tied to a phone number, so the service has it on file even when it’s hidden from the person you call. Apps that never ask for one are covered in Which messaging apps work without a phone number?.
The phone itself. End-to-end encryption protects a call on its way between two phones. It can’t help if someone has access to one of those phones, or is close enough to hear you talk.
Where Krypton Ø fits, honestly
If you need to call anyone at all, Krypton Ø isn’t the app for it. Signal, WhatsApp and FaceTime reach far more people, and they handle video and group calls, which Krypton Ø doesn’t. Calls here are for a small circle: voice only, between Fam, and the person placing the call needs KryptonØ+. Anyone can answer.
There’s also a limit to what our server doesn’t see. The ring is delivered encrypted, so the server isn’t told who is calling whom. But to connect, both phones join the same private channel at the same moment, which lets the server see that two signed-in accounts are in a call right then. It keeps no record of that, but it isn’t blind to it.
Krypton Ø is new and small, it’s on Google Play for Android now with the iPhone app in App Store review, it’s for adults only (18 and over), and you can only join through someone who’s already a member. The reasons it’s closed are in Why Krypton Ø has no open sign-up.
What it costs
Posts, replies, chats and every safety feature in Krypton Ø are free, and so is answering a call. Placing one needs KryptonØ+, which also adds up to 10 photos or videos per post, 5-minute videos, larger files and bigger chats. It’s $49.99 a year or $199 once on the web, or $56.99 a year or $229 once in the app. See KryptonØ+.
FAQ
Are regular phone calls encrypted?
Not end to end. The EFF’s guide says a call from a landline or a mobile phone “is not end-to-end encrypted,” which leaves it open to the phone company and to anyone with power over the phone company. To keep a call private from the network that carries it, use an app that encrypts calls end to end.
Which calling apps are end-to-end encrypted?
Signal, WhatsApp, FaceTime and Threema encrypt one-to-one and group calls end to end. Telegram’s voice, video and group calls are end-to-end encrypted as well. LINE and Viber encrypt one-to-one calls end to end, but not group calls. Krypton Ø encrypts one-to-one voice calls end to end.
Are WhatsApp calls end-to-end encrypted?
Yes, one-to-one and group calls both. Group calls are always relayed through WhatsApp’s servers and stay end-to-end encrypted. For one-to-one calls you can turn on “Protect IP address in calls” so the other person can’t see your IP address.
Are Telegram calls end-to-end encrypted?
Yes. Telegram’s voice calls, video calls and group calls of up to 200 people are end-to-end encrypted, and you can compare four emoji to check. That’s different from Telegram’s ordinary chats, which aren’t end-to-end encrypted, and Telegram doesn’t describe the video chats inside groups as end-to-end encrypted either.
Can the person I call see my IP address?
On a direct, peer-to-peer call, yes. Signal, WhatsApp, Telegram, Viber and Threema each have a setting that relays calls through a server to hide it. Session’s beta calls share your IP address with the person you call. On Krypton Ø every call goes through a relay, so the other person doesn’t see it.
Can an end-to-end encrypted call be wiretapped?
Not on the way. The networks and servers that carry it see only encrypted audio. What encryption can’t protect is either end of the call: someone with access to one of the phones, or someone in the room, can still hear it.