A fantastic and widely recognised alternative is Signal for iOS, (and its counterpart for Android, TextSecure), created by Open Whisper Systems. People like Edward Snowden have been praising it.<p>iOS: <a href="https:&#x2F;&#x2F;itunes.apple.com&#x2F;gb&#x2F;app&#x2F;signal-private-messenger&#x2F;id874139669?mt=8" rel="nofollow">https:&#x2F;&#x2F;itunes.apple.com&#x2F;gb&#x2F;app&#x2F;signal-private-messenger&#x2F;id8...</a><p>Android: <a href="https:&#x2F;&#x2F;play.google.com&#x2F;store&#x2F;apps&#x2F;details?id=org.thoughtcrime.securesms&amp;hl=en_GB" rel="nofollow">https:&#x2F;&#x2F;play.google.com&#x2F;store&#x2F;apps&#x2F;details?id=org.thoughtcri...</a>