Update #1

I have started dealing with easy things for an android port first. One realization was java awt package (images etc.) is not available in android. So, I had to replace all the usages of java awt with their android equivalents (android.graphics package). This is also helpful in objective #1 to handle QR images on android.

Also, I have tested the LZMA compression library and the related fred code on android. It seems to work perfectly i.e. compress and read back cycle using both oldLZMACompressor.java and newLZMACompressor.java.

The github link for android port under development and related testing is https://github.com/NiteshBharadwaj/Fred-Staging-Android 

With respect to QR, I have cloned Operheim's implementation of NoderefQRCode which is a plugin to freenet and can convert node references into QR code and decode them back.

https://github.com/Thynix/NoderefQRCode

Since, this part is already implemented by Operheim, I have just run a few tests.

I tried to scan the generated QR using popular applications available on google app store. It could decode correctly 7 out of 10 times while 3 times it decoded a random number! 

Using the original decoder (in NoderefQR), it gave similar results except that instead of random number it ran into check sum exception once or twice.

The basic problem I noticed is bigger the size of the string to be decoded, the longer it takes (quite irritating) and more the chances of a wrong decode.

During the planning stage, we thought about using QR codes only to establish Wi-Fi Direct connection between two mobiles. The actual node references are exchanged via Wi-Fi direct. This seems a better option compared to encoding whole nodereference in QR (We could provide multiple options anyway). The high band-width during such transfer can also be utilized for sneakernet support later on.