App nameAlloiMessageMessengerSignalSkypeTelegramThreemaViberWhatsappWickrWire
TL;DR: Does the app secure my messages and attachments?NoNoNoYesNoNoYesNoNoNoYes
Company jurisdictionUSAUSAUSAUSAUSAGermanySwitzerlandLuxembourg & JapanUSAUSASwitzerland
Infrastructure jurisdictionUSA, Belgium, Finland, Ireland,the Netherlands, Chile, Taiwan,and SingaporeUSA (Ireland and Denmark planned); iMessage runs on AWS and Google CloudUSA, Sweden (Ireland planned)USAUSA, the Netherlands, Australia, Brazil, China, Ireland, Hong Kong, and JapanUK, Singapore, USA, and FinlandSwitzerlandUSAUSA (unsure of other locations)USA (unsure of other locations)EU
Implicated in giving customers' data to intelligence agencies?YesYesYesNoYesNoNoNoYesNoNo
Surveillance capability built into the app?NoNoNoNoYesNoNoNoNoNoNo
Does the company provide a transparency report?YesYesYesYesYesNoYesNoYesYesYes
Company's general stance on customers' privacyPoorPoorPoorGoodPoorGoodGoodPoorPoorGoodGood
FundingGoogleAppleFacebookFreedom of the Press Foundation, the Knight Foundation, the Shuttleworth Foundation, and the Open Technology FundMicrosoftPavel DurovUser paysRakuten, friends and family of Talmon Marco (it's very unclear)FacebookGilman Louie, Juniper Networks, the Knight Foundation, Breyer Capital, CME Group, and WargamingJanus Friis, Iconical, Zeta Holdings Luxembourg
Company collects customers' data?YesYesYesNoYesYesNoYesYesNoNo
App collects customers' data?YesYesYesMinimalYesYesNoYesYesNoMinimal
Is encryption turned on by default?NoYesNoYesYesNoYesYes (if device supports it)Yes (if device supports it)YesYes
Cryptographic primitivesRSA-1280 (encryption), ECDSA 256 (signing) / AES 128 / SHA-1Curve25519 / AES-256 / HMAC-SHA256Curve25519 / AES-256 / HMAC-SHA256RSA-1536 & 2048 / AES 256 / SHA-1RSA 2048 / AES 256 / SHA-1Curve25519 256 / XSalsa20 256 / Poly1305-AES 128Curve25519 256 / Salsa20 128 / HMAC-SHA256Curve25519 / AES-256 / HMAC-SHA256ECDH512 / AES-256 / HMAC-SHA256Curve25519 / ChaCha20 / HMAC-SHA256
Are the app and server completely open source?NoNoNoYes (messaging is; however, phone calls are not)NoNo (clients and API only)NoNoNoNoNo (clients only)
Can you sign up to the app anonymously?NoNoNoNoNoNoYesNoNoYesNo
Can you add a contact without needing to trust a directory server?NoNoNoNoNoNoYesYesNoNoNo
Can you manually verify contacts' fingerprints?NoNoYesYesNoNo (session only, does not provide users' fingerprint information)YesYesYesYesYes
Directory service could be modified to enable a MITM attack?YesYesYesYesYesYesYesYesYesYesYes
Do you get notified if a contact's fingerprint changes?NoNoYesNoNo (session only, does not provide users' fingerprint information)YesYesNo (setting turned off by default)NoIf contact was previously verified
Is personal information (mobile number, contact list, etc.) hashed?NoNoNoMostlyNoNoYesNoNoYesMostly
Does the app generate & keep a private key on the device itself?YesYesYesYesYesYesYesYesYes
Can messages be read by the company?YesNoYesNoYesYesNoNoNoNoNo
Does the app enforce perfect forward secrecy?NoYesYesNo (session keys do change after being used 100 times)NoYesYesYesYes
Does the app encrypt metadata?NoNoYesNoYesNoYesMostly
Does the app use TLS/Noise to encrypt network traffic?YesYesYesYesYesNoYesYesYesYesYes
Does the app use certificate pinning?Yes (>=iOS 9.3)YesYesYes
Does the app encrypt data on the device? (iOS and Android only)Yes (if passphrase enabled)Yes (if passphrase enabled)iOS: Yes (if passphrase enabled); Android: Yes (if master key set in the app)iOS: Yes (if passphrase enabled); Android: Yes (unsure of function)
Does the app allow a secondary factor of authentication?NoNoNoNoNoYesYesNoNoYes (password for account used)No
Are messages encrypted when backed up to the cloud?NoN/A, Signal is excluded from iCloud/iTunes & Android backupsYesNoN/A, Wire is excluded from iCloud/iTunes & Android backups
Does the company log timestamps/IP addresses?YesYesYesNoYesYesNoYesYesNoSome
Has there been a recent code audit and security analysis?NoNoNoYes (October, 2014)NoYes (Nov, 2015)Yes (November, 2015)NoNoYes (August, 2014)No
Is the design well documented?NoSomewhatSomewhatSomewhatNoSomewhatSomewhatSomewhatSomewhatSomewhatSomewhat
Does the app have self-destructing messages?YesNoYesYesNoYesNoNoNoYesYes

Red = Something of major concern.

Yellow = Something of concern.

Green = Nothing of concern.

Blank = I couldn’t find any information about it.