I purchased some bitcoin a few years ago using Multibit on a Android Tab. I no longer have access to that tablet. This is what I have.
Are you certain it was MultiBit? As far as I am aware... MultiBit was never available on mobile devices... it was Windows, Linux and MacOSX only.
A Bitcoin address verifiable on Blockchain Explorer.
A backup file that looks like this: bitcoin-wallet-keys-date-bytes but seems to have a null ext.
Also have a file called: date6othernumbers.key.
Not sure what the "bitcoin-wallet-keys-date-bytes" is... but MultiBit generally created "backup" files like:
multibit-20190410143351.key
multibit-20190410143351.wallet
multibit-20190410143351.wallet.cipher
MultiBit HD created files like:
mbhd.wallet.aes
My question is, since Multibit is no longer supported, what wallet would give me the best chance of recovery.
Your best bet might be to actually just install an old version of MultiBit (available here:
https://multibit.org/release-info/classic/v0.5.19.html) and try to at least open the .key file that you have using that wallet... it may not be able to sync and/or send transactions, but if you could at least open the file, you might be able to then export the keys and then import them into the wallet of your choice.
In MultiBit classic, you use the "tools -> import private keys" menu option, and then the "import from ..." button:
That will allow you to open the .key file... enter the password and click the unlock button... if the password is correct, it should populate the "Number of Keys" an "Replay Date" fields:
Once you have the keys imported... you can use the "tools -> export private keys" option to create a plaintext export file (don't set an export file password, otherwise you won't actually be able to read the generated .export file as it will be encrypted and you'll be back at square one!
)
NOTE: I've been trying to simply decrypt the .key file on the commandline using OpenSSL following the information posted by the MultiBit devs... but that doesn't appear to be working
However, when I try to load the .key file into multiBit and use exactly the same password as with OpenSSL, it works perfectly and will import the .key file??!?
That's why I recommend to try reading it directly into MultiBit