Which statement accurately describes cryptography?

The statement that accurately describes cryptography is that it is the science of encrypting and decrypting communications. This definition encompasses the core functions of cryptography, which include converting plain text into an unreadable format through encryption and then converting that encrypted information back into a readable format through decryption. Cryptography plays a key role in ensuring data confidentiality, integrity, and authentication in various applications, including secure communications over the internet.

In addition to protecting sensitive information during transmission, cryptography underpins many security protocols and systems that rely on these principles to safeguard data both at rest and in transit. By providing a means of securing communications, cryptography enables secure exchanges in environments where data breaches and eavesdropping are concerns.

Other statements in the options do not accurately capture the full scope of cryptography. For instance, breaking encrypted data without the key focuses on cryptanalysis, which is related to but distinct from the practice of cryptography itself. Focusing solely on unencrypted data overlooks the primary purpose of cryptography, which is to protect data during its transmission. Lastly, while digital signatures are an important aspect of cryptography, the field encompasses much more than just their management, including encryption algorithms, key management, and various cryptographic protocols.