Disable display of passwords on an iPhone?

Once you have defined a passcode to unlock an iPhone, and for every application asking a password, when waiting for a password an iPhone makes a transient display of any character you type. It is clear that this transient display was purposefully set in place to help people who have problems with passwords or with the on screen keyboard. This transient display lasts 3 seconds to avoid too big a security problem. But this is still largely sufficient for anyone behind you to read it really easily. Moreover this transient display can be easily captured by any camera or by a software on the iPhone:

I evaluate this echo of any password as a serious risk. This echo partially exposes a secret.

Is there any simple configuration method to suppress everywhere this mechanism of transient display of any password?

For information, I reported this security problem at Apple:

Once I have defined a passcode to protect my iPhone, and within every application asking me a password, when entering my password iOS makes a transient display of any character I type. I guess that this transient display of passwords was purposefully set in place to help people who have problems with passwords or with the on screen keyboard. This transient display lasts 3 seconds to avoid to create too serious a security problem. But this is still amply sufficient for anyone behind you to read it really easily.

This transient display can be easily captured by a camera surreptitiously activated by a malicious neighbour.

I didin't find any easy way to block this security weakness with iOS 7 up to iOS 9.

How to disable this transient display of any password on iOS?

Solution 1:

You can't, at least not in any iOS version that has been released by Apple.

I understand this isn't the answer you were looking for.