About end-to-end encryption
Learn how HiYou protects eligible messages and media with end-to-end encryption.
End-to-end encryption protects a message while it travels between devices. When a HiYou message is end-to-end encrypted, it is turned into unreadable data on the sender's device and can be opened only by the intended recipients' registered devices.
What HiYou encrypts
HiYou uses end-to-end encryption for supported messages in one-to-one chats and eligible groups. Photos, videos, voice messages, and documents are encrypted before upload, and the information needed to retrieve them is sent through the encrypted chat.
Each linked phone has its own encryption key. HiYou prepares a separate encrypted copy for every active recipient device and for your other linked devices, so the service does not need the readable message to deliver it.
When secure messaging is unavailable
A message can't be sent securely until at least one recipient device has registered a secure-messaging key. HiYou shows a send error and retries later when secure messaging becomes available.
Groups with more than 32 members aren't currently eligible for secure messaging. HiYou does not silently send a failed secure message as ordinary text.
Verify a one-to-one chat
You can compare a chat's safety number with the other person. A matching number helps confirm that you are using the expected device keys.
- Open the one-to-one chat.
- Tap the person's name at the top.
- Tap View safety number.
- Compare the number with the other person using a trusted method.
- Open the one-to-one chat.
- Tap the person's name at the top.
- Tap View safety number.
- Compare the number with the other person using a trusted method.
If either person reinstalls HiYou, changes phones, or updates linked devices, the safety number may change. Compare it again before sharing sensitive information.
If a safety number changes
If you had previously verified someone's safety number and it changes, HiYou shows a warning banner at the top of your chat with them. Tapping it opens the Safety Number screen, which shows This safety number changed since you last verified it. This warning only appears inside the chat itself - HiYou does not send a separate push notification for it, so you'll only see it the next time you open that conversation.
What end-to-end encryption doesn't do
Encryption does not stop a recipient from saving, forwarding, photographing, or reporting content after it reaches their device. It also does not hide basic delivery information needed to operate the service, such as who participates in a chat and when data is sent.