The CEO of Max Rager wants to send a confidential message regarding the new formula for its coveted soft drink, SuperMax, to its manufacturer in Texas. However, he fears the message could be altered in transit. How can he prevent this incident from happening and what element of the message ensures the success of this method?

The primary concern is preventing the message from being altered, which relates to the principle of data integrity. Hashing is the cryptographic method used to ensure integrity. A hash function creates a unique, fixed-size digest (hash code) from the message. The sender sends this hash code along with the message. The recipient recalculates the hash of the received message and compares it to the received hash code. If they match, the message has not been altered.

B. Symmetric encryption; secret key: This provides confidentiality (secrecy) but does not inherently provide integrity protection against alteration.
C. Hashing; public key: Hashing is a one-way function that does not use a public key. Public keys are used in asymmetric cryptography.
D. Asymmetric encryption; public key: This is primarily for confidentiality or authentication (via digital signatures), but the fundamental element that checks for alteration is the hash.

1. Katz, J., & Lindell, Y. (2014). Introduction to Modern Cryptography (2nd ed.). CRC Press. Chapter 5, "Hash Functions and Applications," explains the use of hash functions to create message authentication codes (MACs) and digital signatures for integrity verification.

2. Stallings, W. (2017). Cryptography and Network Security: Principles and Practice (7th ed.). Pearson. Section 2.3, "Cryptographic Hash Functions," details how hash functions are used to detect message modification.