The Electronic Frontier Foundation has released an interesting comparison chart showing how well the most common instant messaging platforms compete on security.
The EFF analysis looked at these criteria:
- Encrypted in transit
- Encrypted so the provider can't read it
- Can you verify contacts identity
- Are past communication protected if keys are stolen
- Is the code open to independent review
- Is security design properly documented
- Has the code been audited
The highest rated tools (scoring 7 out of 7) were:
- Silent Phone
- Silent Text
Not surprisingly, Apple's Facetime & iMessage (Messages) were ranked as the most secure mass market messaging tools.