πŸ”’

LifeArc Ecosystem

Messages across time.

Receive, wait, open. Encrypted time capsules that unlock exactly when they should. No cloud. No third party. Just you and time.

No cloud Offline AES-256-GCM Free for recipients

Download Apps

Scan the QR code or tap the button β€” download starts immediately.

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⚠️ Beta β€” APK files available for direct download. iOS coming soon.

Time Capsules

A message, photo or note that unlocks exactly on the day you set. Not earlier. Not after changing the clock. Not without the correct password.

Locked
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Letter for 18th birthday
Opens: June 15, 2034
calculating...
remaining until unlock
Pending verification
⏳
Letter to my future self
Unlocking: today 12:00
00d 00h 42m
verifying time via 4 servers...
Unlocked
πŸ”“
Grandma's recipe
Unlocked: January 1, 2025
Enter password
the time has come β€” read the message
πŸ•°οΈ
Changing the clock won't help
The capsule won't unlock early β€” not even if you change the clock. Time is verified via 4 independent servers (worldtimeapi.org, Cloudflare, Google, timeapi.io). Manipulation is detected.
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Forgotten password = content lost forever
Capsule content is encrypted with AES-256-GCM. That's by design, not a bug. A forgotten password means the content is gone forever.
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Works offline
A capsule stored on your phone waits for years without needing a connection. Internet is only required at the moment of unlocking to verify the exact time.
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No cloud, no server
Your data stays on your phone only. No registration, no cloud backup. Your phone is your server.

The story of one capsule

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Scenario: Petr and his daughter

Petr creates a capsule in LifeArc named "Letter for 18th birthday". He writes a letter, attaches photos and sets the unlock date: June 15, 2034, 00:00. He exports a file called deti.arc, copies it to a USB drive and gives it to his daughter along with the password.

His daughter downloads LifeArc Receiver β€” free, no registration. She opens the file, enters the password and sees the capsule locked with a countdown. She waits 10 years.

On the morning of June 15, 2034 the app wakes her with a notification: "Capsule is unlocked." She enters the password. She reads the letter.

β€” real usage scenario Β· author: Petr VeselΓ½

How it works

Did you receive a .arc file? Five steps and you're all set.

1
πŸ“¬
Receive the file
Email, Bluetooth, AirDrop or USB drive β€” a .arc file and its password.
2
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Install the app
LifeArc Receiver β€” free on Google Play and App Store. No registration, no ads.
3
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Enter Master Password
The file password from the sender. The app shows a list of capsules with locked content.
4
⏳
Wait
Capsules show a countdown. The app schedules a notification. You wait days, months, years.
5
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Open
On the unlock day a notification arrives. Enter the Capsule Password and read the message.

Double encryption

Every capsule has two layers of protection. Even if someone gets the file, without the password they see nothing.

LifeArc Receiver
deti.arc
3 capsules Β· container unlocked
πŸ”’
Letter for 18th birthday
Locked
4382 d
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Childhood photos
Locked
4388 d
πŸ”“
Grandma's recipe
Unlocked
Read
deti.arc
+
Master Password
β†’
Capsule list
(names and dates only)
↓ each capsule separately
Capsule Password
+
unlock date
β†’
Capsule content βœ“
Master Password
Password for the whole file. You get it from the sender right away.
Capsule Password
Password for a specific capsule. Can be passed on the unlock day itself.

All features

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Double AES-256-GCM encryption
Every capsule has its own password. The file has a Master Password. No one else can open the content.
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Notifications years in advance
The app schedules an alert for the exact unlock date β€” works even after a phone restart.
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Works offline
You need internet only at the moment of unlocking to verify the exact time. Everything else is offline.
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No cloud
Your data stays on your phone only. We send nothing anywhere. No server, no registration.
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Free for recipients
LifeArc Receiver is free with no ads, no in-app purchases and no hidden fees.
🌍
Czech and English
The app is fully localized. Switch language at any time in Settings.

Encryption without compromise

Algorithm
AES-256-GCM
Military-grade standard. Authenticated encryption with integrity verification.
Key derivation
PBKDF2
SHA-256, 100,000 iterations. Resistance against brute-force attacks.
Parameters
Salt + Nonce
  • Salt: 16 B random
  • Nonce: 12 B random
  • Auth tag: 16 B
  • Format: base64
Time verification
4 servers
  • worldtimeapi.org
  • Cloudflare trace
  • Google HEAD request
  • timeapi.io

Two projects, one goal

LifeArc creates capsules. LifeArc Receiver opens them. Together they form a complete ecosystem for time-locked messages.

🏰
LifeArc
For senders
Full-featured application. Vaults, calendar, time capsules, notes and to-do. Full control over your data.
More about LifeArc β†’
πŸ“¬
LifeArc Receiver
For recipients Β· Free
Simple app for recipients. Opens .arc files, shows countdowns and notifies you at the right time.
How it works β†’

Have questions?

What is a .arc file? βŒ„

A .arc file is an encrypted container created by the LifeArc app. It contains time capsules β€” messages, photos or recordings that unlock at a pre-set time. The file is encrypted with AES-256-GCM and is unreadable without the password.

Do I need an internet connection? βŒ„

Only to verify the exact time when unlocking a capsule. If the sender set an offline tolerance (6h, 24h or 48h), the app works without internet too. Capsules wait offline for years.

Where is my data stored? βŒ„

Exclusively on your phone. The app sends nothing anywhere. There is no server, no cloud, no registration. Your data is yours and stays with you only.

I have two passwords β€” what do I do with them? βŒ„

Master Password opens the whole file and shows the list of capsules (but not their content). Capsule Password is the password for a specific capsule β€” the sender can give it to you right away, or hand it over on the unlock day via a third person, a letter, etc.

What if I lose my phone? βŒ„

Import the .arc file again into a new app instance and enter the password. We recommend keeping the file backed up β€” email, cloud, another device. The file itself is unreadable without the password, so it's safe to have multiple copies.