The term 'USES A KEY ON, PERHAPS' can be decoded as 'DECODES', which is a 7-letter word. Decoding is the process of translating encoded information into its original form. It is commonly used to protect data from unauthorized access or to make it difficult for someone to understand the meaning of the data. In cryptography, decoding is done using a key, which is a secret code that only the intended recipient knows. This key is used to decipher the encrypted data, allowing the recipient to access the information.