This is according to the Electronic Frontier Foundation (EFF) who has ranked Apple’s iMessage as one of the best mass-market options right now, although the EFF also points out that there are dedicated apps such as ChatSecure, Signal, and CryptoCat which score even higher due to the fact that they are designed for secure messaging, although chances are they aren’t as popular compared to the options listed above.
In order to score these apps based on their security, the EFF asked questions such as whether or not the message is encrypted in transit; is it encrypted to the point where the provider can’t even read it themselves; can the user verify the identities of their contacts; is past communications secure if keys are stolen; is the code open to independent review; has the code been audited?
The scorecard is pretty comprehensive and if you’re truly worried about the security of your messages being sent and received on your phone, perhaps you can check out the scorecard to see which apps are worth checking out, especially if you’re in need of such a secure messaging platform.