Homomorphic Encryption is the process of performing operations on encrypted data without decrypting it first. It has often been referred to as the holy grail in cryptography and distrubted computing. It has also been researched by the largest companies in the world such as IBM.
DERO is a general purpose platform for building unstoppable decentralised applications and securely storing and transferring value. It is an original protocol which has been built from scratch and is maintained by the developer team who created it. This is not a fork or translation of any other layer 1 (L1) blockchain protocol.
Trusted Execution Environment is a method like Homomorphic Encryption, to perform operations on data in a form of encrypted state, this form is quite different though. TEE’s work by taking in encrypted data and decrypting it into an encrypted trusted area (called an enclave with Intel SGX) where operations can be performed on the data behind encryption for privacy. The trust in this setup comes from having the data in a decrypted state and having to rely on the surrounding “enclave” to be secure. If you did not create this area, if it is proprietary, then you are trusting it is secure.
The Cryptonote protocol used by Monero, Zano, Haven and a lot of other projects quite often seems to get conflated with encryption when Cryptonote uses sender/receiver obfuscation as key images and stealth addresses. This is partly due to the UTXO model not lending itself to encryption as well as an account model does.