What do you mean by "a keystore"? Do you mean specifically the OSs, keystore? (Most OSs have one.) Or something else?
You'd have to write a Rhodes extension, and you'd have to implement it for each platform you intend to support. You'll have to obtain the documentation on how to use the native keystore, and write an extension to wrap it.
This would be a useful addition to Rhodes in the developer's spare time.
iOS calls it a "keychain":
Yes i would like to key store which most OSs have like Key chain in iOS as you mentioned!!.
Indeed this will be a useful addition to Rhodes.But as i have timing constraints is there any alternative to this??
Basically i want to store some key-value pair within the app where it is more secured as compared to when stored in Database.
Is there any existing Rhodes extension/API to do this??
You could use a licensed (paid) version of RhoMobile Suite, and then you gain ability to encrypt the database. This may or may not meet your requirement. You may have some specific need to interact with the native keystore. (Maybe it is an approved security solution for your requirement, or maybe you need to share keys with other devices using OS features.)
The big advantage is that if this does meet your requirement, it meets it instantly. (OK, you have to configure to encrypt the database.)
If you need to use the native keystore, I'm not aware of any supplied extension that does this. You'll have to seek a third-party solution or else write it yourself.
Writing a native extension is not that difficult. At least for iOS. (I haven't done it for Android. It would be difficult for me, because I do not write Java!)