what i really think of computers and the internet

computers once connected to the internet are prone to privacy breaches. in layman thinking, i believe any form of transaction such as internet banking etc. performed over the internet can be sniffed and decrypted. There is no 100% encryption. even for blockchain, i keep on pondering if the creator has some form of master key that can synchronise every node, making even fake transactions deem valid.
till today, no one has an answer to the above, even there is, it will be held in the highest secrecy. just my few words…