Keepluma
How your photos and videos travel securely
Each device keeps its own private key without uploading it to the server. Before transferring photos and videos, the devices authenticate each other with TLS and establish session keys. Media is encrypted and decrypted only on the devices. The relay server has neither the device private keys nor the session keys, so it cannot decrypt the media it forwards.
Sending device
Encrypt, then send
Private key kept only on this device
Relay server
Forwards ciphertext; cannot decrypt it
Receiving device
Receive and decrypt after identity checks
Private key kept only on this device
Why can’t the server open your photos?
Each device generates and keeps its own identity private key; that key is not uploaded to the server. When transferring photos and videos, both devices use their private keys for TLS authentication and establish session keys known only to the communicating devices. Media is encrypted before it leaves the sender and decrypted only at the receiver. The relay server has neither the device private keys nor the session keys for that transfer, so it cannot turn the ciphertext it forwards back into photos or videos.
Verify the device before sending media
Encryption is paired with checks of the peer device’s identity and the intended connection target. These checks help prevent media from being sent to the wrong device. Access to content is allowed only after identity and permission checks pass.
Altered data is not accepted as the original
Transfer protection detects tampering, and the receiving device also checks file integrity. A backup is complete only after the files are fully saved and verified. Sending progress reaching 100% does not, by itself, mean the backup is safely stored.