Which symmetric cipher was specifically developed for the clipper chip?

The symmetric cipher specifically developed for the Clipper Chip is Skipjack. The Clipper Chip was introduced by the U.S. government in the early 1990s as a cryptographic device intended to secure voice communications. Skipjack was designed to operate at a 64-bit block length and utilizes a unique key management system under key escrow, which allowed government authorities to access the encrypted data if necessary.

Unlike other ciphers, Skipjack's development was closely tied to the Clipper Chip initiative, making it distinctively aligned with its purpose and functionality. Other options such as DES, while also a symmetric cipher, was not created specifically for the Clipper Chip; it was already in widespread use and had been adopted long before the introduction of the Clipper Chip. AES, developed later, is not related at all, as it was designed to replace DES and strengthen encryption standards. RSA, on the other hand, is an asymmetric encryption algorithm, fundamentally different from symmetric ciphers like Skipjack. Thus, Skipjack stands out as the cipher directly associated with the Clipper Chip's design and objectives.