Don't pass on small block ciphers
Summary
The article argues that while small block ciphers (32- or 64-bit) are common in constrained environments, they carry significant security drawbacks and are not suitable as general-purpose ciphers. It discusses practical uses and mitigations, including encrypting counters and UUID components, and reviews design options (SIMON/SPECK) while recommending caution and use as a toolbox rather than a default choice.