A technology company recently onboarded a new customer in the medical space. The customer needs a solution to provide data integrity across remote…

Data integrity ensures that information has not been altered in an unauthorized manner during transmission. Hashing is the fundamental cryptographic process used to provide data integrity. A hashing algorithm creates a unique, fixed-length string of characters, known as a hash value or message digest, from the original data. This hash is sent along with the data. The receiving end recalculates the hash from the received data and compares it to the original hash. If they match, the data's integrity is verified. In secure communications like IPsec used in SD-WAN, this is often implemented using a Hashed Message Authentication Code (HMAC), which combines a secret key with the hash function to also provide message authentication.

B. data masking: This is a data security technique used to create a structurally similar but inauthentic version of an organization's data, primarily for privacy in non-production environments.

C. preshared key: A preshared key (PSK) is a shared secret used for authentication between two parties to establish a secure connection, not for verifying the integrity of the data itself.

D. authentication: This is the process of verifying the identity of a user or device. While essential for security, it does not guarantee that the data exchanged has not been tampered with.

1. Cisco SD-WAN Security Configuration Guide, Cisco IOS XE Release 17.x: In the section "Configure Security Parameters in a Security Policy," the guide specifies the integrity mechanism. It states, "For integrity, you can configure one of the Secure Hash Algorithms: SHA-1 HMAC or SHA-2 HMAC." This directly links hashing algorithms (SHA) to the data integrity function within a Cisco SD-WAN solution.

2. NIST Special Publication 800-131A Revision 2, "Transitioning the Use of Cryptographic Algorithms and Key Lengths" (December 2018): Table 3, "Strength and supported usage for approved hash functions," outlines the approved hash functions (e.g., SHA-256, SHA-384) for digital signatures and other applications requiring data integrity. Section 4 explicitly discusses the role of hash functions in providing integrity.

3. Cisco, "IP Security (IPsec) Protocol": In the documentation describing IPsec services, it states, "Data integrity: The IPsec receiver can check whether data was modified in transit... IPsec uses a hash algorithm, such as SHA, to provide data integrity." This is from official Cisco vendor documentation explaining the core security protocol.