An algorithm is a set of steps that can be sequenced and repeated. The algorithm is used to define which encryption formula will be used when data is encrypted and unencrypted.
Key pair encryption systems rely on a public and private key for encryption and decryption of data. The public key is freely distributed to any agent that needs secure communications with the holder of the matching private key.
Hashing takes information and scrambles it into unreadable gibberish. Hashing strength is measured in bits with a longer value representing stronger (more difficult to break) encryption.
Symmetric encryption uses the same key (private) on both sides of the encryption process. Symmetric encryption is fast but is easier to compromise ...