Speck
A lightweight block cipher published by the NSA in 2013, controversial for its origin and thin design rationale.
Speck was published in 2013 by researchers at the NSA as part of a family of lightweight ciphers, alongside Simon. It is built for very small processors and uses only addition, rotation and XOR on words, which keeps the hardware cost low.
Critics pointed out that the designers explained their choices sparingly. The NSA connection led many people to avoid it, even though the cipher is technically reasonable.