Certified Bitcoin Professional Practice Exam

Symmetric encryption is characterized by the use of a single key for both the encryption and decryption processes. This means that the same key that is used to encrypt the plaintext must be used to decrypt the ciphertext back into plaintext. This method is efficient and fast, making it suitable for encrypting large amounts of data. The requirement for the key to remain secret and shared between the parties involved in the communication is crucial, as any compromise of the key can lead to the security of the entire communication being jeopardized. Because both the sender and the recipient use the same key, symmetric encryption emphasizes the need for secure key management and distribution methods to prevent unauthorized access. The other options describe characteristics that do not align with symmetric encryption. For example, using two different keys pertains to asymmetric encryption, which is fundamentally different and requires a pair of keys (public and private) for the encryption and decryption processes. The mention of three keys or the absence of key exchange does not accurately represent the standard processes associated with symmetric encryption either. Thus, the defining trait of symmetric encryption is its reliance on a single key that is used for both functions of the encryption cycle.