Final answer:
Plaintext is the natural and readable data format, while hardware-based encryption uses specialized devices for security. Algorithms, crucial in encryption and decryption, can make it feasible to decode signals, including hypothetically encrypted alien messages.
Step-by-step explanation:
The message or data in its natural format and in readable form is known as plaintext. Hardware-based encryption uses a device with a processor designed specifically to authenticate users and encrypt data. Algorithms are mathematical functions that are used in the encryption and decryption processes. They can be quite simple or extremely complex.
Cell phone conversations, and television voice and video images are commonly transmitted as digital data, through a process called digital modulation, which converts the analog signal into a sequence of binary ones and zeros. This binary sequence, or bits, can be encrypted for secure communication and then decrypted at the receiving end using the correct encryption key and algorithms. The challenge of deciphering the code becomes particularly intriguing when considering the potential for encountering an alien message, as it may not conform to any human-anticipated formats or encodings.