Question 1

What encryption does Arc use?

Accepted Answer

Arc encrypts messages on the device. 1:1 chats use libsignal with PQXDH (standardized ML-KEM-1024) when both devices support it and the Double Ratchet; group chats use a shared key sent to each member separately, which is not post-quantum.

Question 2

Is Arc quantum-resistant?

Accepted Answer

Arc's completed product specification uses standardized ML-KEM-1024 with PQXDH for hybrid post-quantum session establishment.

Question 3

Can Atlas Associates read my messages?

Accepted Answer

Arc's completed product specification minimizes server access to message content. Routing metadata such as recipient, network address, timing, size, and push-provider observations may still remain visible.

Question 4

Does Arc sell my data?

Accepted Answer

No. Atlas Associates Inc. does not sell, rent, lease, or trade user data to advertisers, data brokers, or third parties. We do not run advertising based on the content of your communications. Our business model does not require monetizing user data, and we have no plans to introduce one that would.

Question 5

How long does Arc store my messages?

Accepted Answer

Each message has a sender-configured expiry time. At expiry, the device copy disappears immediately. The encrypted server copy is purged on a plan-tiered schedule: Essential daily at 00:00 JST (up to 24 hours), Premium every 6 hours at 00:00, 06:00, 12:00 and 18:00 JST (up to 6 hours), and Intelligence every 5 minutes. These are normal-operation maximum delays; a service failure can extend them. Mutual Burn (Vanish-on-Read) is available on all plans for 1:1 chats: when both parties tap the mail icon to confirm read, a burn animation overlays the message and the plaintext is purged from devices. Group chat support is planned for a future release.

Question 6

Does Arc require a phone number?

Accepted Answer

No. Arc uses human-readable Arc IDs (e.g. arc_XXXX) instead of phone numbers. This means you do not reveal your phone number to other users, and Arc accounts are not tied to your phone number or carrier.

Question 7

Is Arc free?

Accepted Answer

Yes. Essential is free with full end-to-end encryption. Premium is free through November 30, 2026, with unlimited switching during this period; on December 1, accounts that switched to Premium for free return to Essential, while active promo-code trials stay on Premium until they end. Intelligence is an invite-only beta managed by Arc operations, with a planned general-release price of US$25/month or US$250/year.

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