i suggest you stay away from crypto currencies until you learn some basic tings first! it seems like you are way too confused.
litecoin is an altcoin
blockchain.info is a bitcoin wallet, you can't use one for the other.
I use 2 layer encryption with password phone and authenticator.
Still i receive feedback quoting that any online wallet can be hacked into even when you re using a Linux Host and madly strong passwords.
when you are online, a simple key logger can steal your passwords and have access to your wallet, private keys and in one word your money.
and even if you use a strong password you are still putting your trust in a third party to have strong security in their encryption and storage.
Fact also is that a company like
https://blockchain.info/ could go bankrupt or just disappaer from the our planet whatever
you have access to your private keys which means even if you someday can not open blockchain.info website you can still spend bitcoin with the keys.
My question is : I would like to buy altcoin but i want to be 100 safe.
you again use the word altcoin.
alt+coin is alternative coins which means alternative to bitcoin. in short any crypto currency that is not bitcoin is called altcoin.
i feel like you are mixing these two. and in fact want to invest in bitcoin.
I guess i need a hardware device but here again i hear rumours about backups more then 2 terrabyte etc etc etc....
don't know where you bring 2 TB! there are full node wallets such as bitcoin core which store the whole blockchain (don't confuse with blockchain.info the website) and the size of it is 100 GB
you can buy a hardware wallet, it is just a device.
you can also research what cold storage is.
Does this mean i will need to buy several of them hardware devices if i buy more altcoin....Them things consume so much HD space....
again! revise your question.
Also i wonder about my online wallet at
https://blockchain.info/What do i do after i exported all my products to them HD devices? There s no link on
https://blockchain.info/ with info how to delete an online account.
Still my data is upthere in them databases....
i am not sure what you ask here. but don't put your data there if you are not sure about them!
I also wonder what would be the best HD device for storing several altcoins on the longrun. I m talking about 10 years or something
there is no one wallet that can store multiple altcoins.