DECO is a protocol that enables users to prove the authenticity of data obtained from a specific web server via the TLS protocol without revealing the data itself, which simplifies its adoption as it requires no server-side cooperation. Utilizing interactive zero-knowledge proofs (ZKPs), specifically a VOLE-based ZKP, DECO ensures privacy and efficiency in proving data authenticity, as the interactive nature of TLS makes it suitable for such protocols. The protocol employs a commit-and-prove system for securely computing and verifying data circuits, emphasizing privacy and scalability. DECO's ZKP core features an additively homomorphic commitment scheme, allowing efficient evaluation of logical circuits. The blog post is the first in a series exploring DECO's transition from academic research to practical application, detailing its mechanisms for proving data authenticity, parsing responses, hiding data lengths, and managing proofs across multiple TLS responses.