SECURITY FOUNDATION
ML-KEM-1024 + Signal Protocol
PQXDH, Double Ratchet, Sender Keys, and explicit downgrade prevention.
COMPLETED Arc PRODUCT SPECIFICATION
COMPLETED Arc PRODUCT SPECIFICATION
These eleven capabilities form one completed product specification and are evaluated together as Arc.
COMPLETED Arc PRODUCT SPECIFICATIONPUBLICLY DOCUMENTED MARKET SNAPSHOT · 2026-07-31Arc · 2026-08-26
Competitor cards link to first-party sources. Arc's card is bound to its completed product specification and the same scoring model.
The short answer
COMPLETED Arc PRODUCT SPECIFICATION
These eleven capabilities form one completed product specification and are evaluated together as Arc.
DATA CONTROL
IGF + Mutual Burn
Timer, read, and tap events converge on durable device/server retirement.
RESILIENCE
Ogg Opus voice at 16 kbps + Mesh
COMPLETED Arc PRODUCT SPECIFICATION
Arc
COMPLETED Arc PRODUCT SPECIFICATION
These eleven capabilities form one completed product specification and are evaluated together as Arc.
Standardized ML-KEM-1024 + PQXDH
Double Ratchet DM
Sender Keys Groups
Sealed Sender + anonymous delivery
IGF
Mutual Burn
Key Sync + multi-device
Ogg Opus voice at 16 kbps
Signed direct Mesh DM and Group
Direct Mesh E2EE DM
Bounded multi-hop and store-and-forward
What Arc deliberately leaves out
Product focus is also a security decision. Arc removes or rejects behavior that weakens message integrity, user control, or operational clarity.
- No Group Mutual Burn: Mutual Burn remains a one-to-one agreement.
- Read-or-Lose is retired: important unread messages are not destroyed merely because time passed.
- No silent downgrade from PQXDH, Sealed Sender, or Mesh E2EE to a weaker mode.
- No embedded AI personalities, translation models, pet assistants, or summary models inside Arc's messaging core.
- Mesh E2EE Group is outside the core product promise; signed non-E2EE Group and E2EE DM remain separate modes.
Encryption vs. E2EE vs. PQC
Being encrypted, being end-to-end encrypted, and using post-quantum protection are distinct concepts that can be layered.
Layer 1 · BASIC
Encryption
A broad term covering transport encryption such as TLS and server-side storage encryption. The operator may hold keys and be able to access plaintext.
Layer 2 · STRONG
End-to-End Encryption (E2EE)
Only conversation endpoints hold the content keys, so the service operator should not be able to read message plaintext. Encrypted does not automatically mean E2EE.
Layer 3 · QUANTUM-SAFE
Post-Quantum Cryptography (PQC)
Hybrid post-quantum session establishment with classical key agreement and no silent downgrade to a legacy path.
Encryption / E2EE / PQC Classification
The 19 market products are grouped by the encryption baseline, documented E2EE availability, and documented post-quantum status.
Encryption (TLS + server-side)
20 / 20Transport and server-side storage protection form the baseline category.
Competitor cards link to first-party sources. Arc's card is bound to its completed product specification and the same scoring model.
Signal90
Arc89
iMessage76
Threema72
Wire71
WhatsApp67
Element / Matrix60
Facebook Messenger54
Session53
Google Messages44
Viber39
LINE38
Telegram37
XChat33
KakaoTalk23
Google Chat21
Discord19
Slack17
Chatwork14
Instagram DM14
E2EE (End-to-End Encryption)
Whether public documentation says the service operator cannot read message plaintext.
✓E2EE by default(9)
Signal90
iMessage76
Threema72
Wire71
WhatsApp67
Facebook Messenger54
Session53
Viber39
Arc89
△Limited / partial / opt-in(7)
Element / Matrix60
Google Messages44
LINE38
Telegram37
XChat33
KakaoTalk23
Discord19
—No verified first-party evidence found(4)
Google Chat21
Slack17
Chatwork14
Instagram DM14
PQC (Post-Quantum Cryptography)
Publicly documented status of protection designed for quantum-era attacks.
✓Production deployed(3)
Signal90
iMessage76
Arc89
○Research / planning(2)
Wire71
Session53
—No verified first-party evidence found(15)
Threema72
WhatsApp67
Element / Matrix60
Facebook Messenger54
Google Messages44
Viber39
LINE38
Telegram37
XChat33
KakaoTalk23
Google Chat21
Discord19
Slack17
Chatwork14
Instagram DM14
Tier Ranking
Tier classification by total score and use case. S Tier emphasizes privacy and modern cryptography; D Tier covers productivity tools without E2EE.
S Tier85+Privacy-focused + state-of-the-art cryptography
Signal
#1
Arc
#2
A Tier60–84E2EE sufficient for personal privacy
iMessage
#3
Threema
#4
Wire
#5
#6
Element / Matrix
#7
B Tier40–59Some E2EE, with design constraints
Facebook Messenger
#8
Session
#9
Google Messages
#10
C Tier20–39Custom or limited E2EE, with reliability concerns
Viber
#11
LINE
#12
Telegram
#13
XChat
#14
KakaoTalk
#15
Google Chat
#16
D Tier<20Not designed for confidential personal messaging
Discord
#17
Slack
#18
Chatwork
#19
Instagram DM
#20
9-Axis Scoring (out of 100)
Competitor cards link to first-party sources. Arc's card is bound to its completed product specification and the same scoring model.
| Service | Crypto (18) | FB Sec (14) | PQC (14) | E2EE (13) | Sender (10) | Reg (10) | Ephem (11) | Verify (5) | Multi-Dev (5) | Total |
|---|---|---|---|---|---|---|---|---|---|---|
#1 Signal | 18 | 14 | 14 | 13 | 10 | 6 | 5 | 5 | 5 | 90 |
#2 Arc | 18 | 14 | 14 | 12 | 3 | 9 | 11 | 4 | 4 | 89 |
#3 iMessage | 17 | 13 | 14 | 13 | 5 | 4 | 1 | 4 | 5 | 76 |
#4 Threema | 16 | 13 | 2 | 12 | 7 | 10 | 5 | 4 | 3 | 72 |
#5 Wire | 16 | 13 | 4 | 11 | 5 | 7 | 6 | 4 | 5 | 71 |
#6 WhatsApp | 18 | 13 | 7 | 11 | 0 | 4 | 5 | 4 | 5 | 67 |
#7 Element / Matrix | 13 | 12 | 1 | 10 | 4 | 8 | 3 | 4 | 5 | 60 |
#8 Facebook Messenger | 15 | 11 | 0 | 10 | 0 | 4 | 5 | 4 | 5 | 54 |
#9 Session | 9 | 2 | 1 | 10 | 10 | 10 | 5 | 3 | 3 | 53 |
#10 Google Messages | 15 | 11 | 0 | 8 | 0 | 1 | 2 | 3 | 4 | 44 |
#11 Viber | 10 | 9 | 1 | 7 | 0 | 1 | 4 | 3 | 4 | 39 |
#12 LINE | 13 | 3 | 0 | 9 | 0 | 4 | 2 | 4 | 3 | 38 |
#13 Telegram | 10 | 7 | 0 | 3 | 0 | 4 | 4 | 4 | 5 | 37 |
#14 XChat | 11 | 0 | 0 | 4 | 0 | 9 | 2 | 2 | 5 | 33 |
#15 KakaoTalk | 7 | 4 | 0 | 3 | 0 | 1 | 2 | 2 | 4 | 23 |
#16 Google Chat | 10 | 0 | 0 | 4 | 0 | 1 | 1 | 0 | 5 | 21 |
#17 Discord | 7 | 3 | 0 | 3 | 0 | 1 | 0 | 0 | 5 | 19 |
#18 Slack | 10 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 5 | 17 |
#19 Chatwork | 8 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 5 | 14 |
#20 Instagram DM | 5 | 0 | 0 | 0 | 0 | 1 | 4 | 0 | 4 | 14 |
Axis Legend
Crypto/ Cryptographic Primitives
(18)Algorithm design quality, AEAD and signature schemes, and formal-verification history
FB Sec/ Forward/Backward Secrecy
(14)Protection of past and future messages after key compromise, such as Double Ratchet or MLS
PQC/ Post-Quantum
(14)Publicly documented production status of post-quantum cryptography such as PQXDH or ML-KEM
E2EE/ E2EE Coverage
(13)Default status and coverage across text, calls, groups, and media, including public audit evidence
Sender/ Sender Privacy
(10)Sender and relationship-metadata minimization, including Sealed Sender or onion routing
Reg/ Registration Privacy
(10)Availability of signup without a phone number or email and of an anonymous identifier
Ephem/ Ephemeral Messages
(11)Granularity and lifecycle of disappearing-message controls
Verify/ Verification UX
(5)Usability of key verification, such as Safety Numbers or contact-key verification
Multi-Dev/ Multi-Device
(5)Cross-device key handling without an always-online primary phone
Total
(100)Weighted sum across 9 axes (maximum 100)
20-product evidence and specification cards
Competitor cards link to first-party sources. Arc's card is bound to its completed product specification and the same scoring model.
Primary-source evidence checked 2026-08-26
Each primary source supports only the category where it is cited; it does not substantiate every claim or score and does not imply vendor endorsement.
#1 Signal
STotal 90 / 100
Documented status
E2EE · E2EE by defaultPQC · Production deployed
Primary sources
#2 Arc
STotal 89 / 100
Standardized ML-KEM-1024 + PQXDH · Double Ratchet DM · Sender Keys Groups · Sealed Sender + anonymous delivery · IGF · Mutual Burn · Key Sync + multi-device · Ogg Opus voice at 16 kbps · Signed direct Mesh DM and Group · Direct Mesh E2EE DM · Bounded multi-hop and store-and-forward
#3 iMessage
ATotal 76 / 100
Documented status
E2EE · E2EE by defaultPQC · Production deployed
Primary sources
#4 Threema
ATotal 72 / 100
Documented status
E2EE · E2EE by defaultPQC · No verified first-party evidence found
Primary sources
#5 Wire
ATotal 71 / 100
Documented status
E2EE · E2EE by defaultPQC · Research / planning
Primary sources
#6 WhatsApp
ATotal 67 / 100
Documented status
E2EE · E2EE by defaultPQC · No verified first-party evidence found
Primary sources
#7 Element / Matrix
ATotal 60 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#8 Facebook Messenger
BTotal 54 / 100
Documented status
E2EE · E2EE by defaultPQC · No verified first-party evidence found
Primary sources
#9 Session
BTotal 53 / 100
Documented status
E2EE · E2EE by defaultPQC · Research / planning
Primary sources
#10 Google Messages
BTotal 44 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#11 Viber
CTotal 39 / 100
Documented status
E2EE · E2EE by defaultPQC · No verified first-party evidence found
Primary sources
#12 LINE
CTotal 38 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#13 Telegram
CTotal 37 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#14 XChat
CTotal 33 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#15 KakaoTalk
CTotal 23 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#16 Google Chat
CTotal 21 / 100
Documented status
E2EE · No verified first-party evidence foundPQC · No verified first-party evidence found
Primary sources
#17 Discord
DTotal 19 / 100
Documented status
E2EE · Limited / partial / opt-inPQC · No verified first-party evidence found
Primary sources
#18 Slack
DTotal 17 / 100
Documented status
E2EE · No verified first-party evidence foundPQC · No verified first-party evidence found
Primary sources
#19 Chatwork
DTotal 14 / 100
Documented status
E2EE · No verified first-party evidence foundPQC · No verified first-party evidence found
Primary sources
#20 Instagram DM
DTotal 14 / 100
Documented status
E2EE · No verified first-party evidence foundPQC · No verified first-party evidence found
Primary sources
What the comparison makes clear
These eleven capabilities form one completed product specification and are evaluated together as Arc.
Metadata privacy is a separate battlefield
Strong content encryption does not hide sender relationships by itself. Sealed Sender and anonymous delivery are treated as independent product work.
Offline does not automatically mean E2EE
Arc separates signed non-E2EE disaster communication from E2EE Mesh DM and labels the active mode instead of blurring the distinction.
Deletion is a lifecycle, not an animation
IGF and Mutual Burn are designed around durable device/server retirement, retry, and recovery—not only disappearing UI.
Arc messaging architecture: direct answers
Concise answers to the questions readers and answer engines ask most often about Arc's security and disaster communication design.
What is Standardized ML-KEM-1024 + PQXDH in Arc?
Hybrid post-quantum session establishment with classical key agreement and no silent downgrade to a legacy path.
What is Double Ratchet DM in Arc?
Atomic ratchet advancement, exact-ciphertext retry, bounded skipped keys, and crash-safe recovery for normal one-to-one chat.
What is Sender Keys Groups in Arc?
Per-sender, per-device group epochs with membership fencing and SKDM delivery over authenticated one-to-one sessions.
What is Sealed Sender + anonymous delivery in Arc?
Purpose-separated sender certificates, opaque recipient inboxes, generic push, and a no-plaintext-fallback rule.
What is Signed direct Mesh DM and Group in Arc?
Direct disaster messaging with authenticated origin and integrity, explicitly labeled non-E2EE because relays or nearby observers may see content.
What is Direct Mesh E2EE DM in Arc?
A separate direct-message mode with end-to-end encrypted content, explicit trust state, and no silent fallback to signed non-E2EE delivery.
What is Bounded multi-hop and store-and-forward in Arc?
Resource-bounded relay, deduplication, TTL, and offline recovery without claiming a guaranteed distance, route, or delivery time.
Comparison basis & disclosure
- Competitor cards link to first-party sources. Arc's card is bound to its completed product specification and the same scoring model.
- Each primary source supports only the category where it is cited; it does not substantiate every claim or score and does not imply vendor endorsement.
- Vendor names and marks belong to their respective owners. Inclusion does not imply partnership, endorsement, or affiliation.
Security
Arc Security Details
These eleven capabilities form one completed product specification and are evaluated together as Arc.
Technology
Arc Technology
These eleven capabilities form one completed product specification and are evaluated together as Arc.