Portland Sea Dogs
The authors present the Protected-IV construction (PIV) a simple, modular method for building variable-input-length tweakable ciphers. At their level of abstraction, many interesting design opportunities surface. For example, an obvious pathway to building beyond birthday-bound secure tweakable ciphers with performance competitive existing birthday-bound-limited constructions. As part of their design space exploration, they give two fully instantiated PIV constructions, TCT1 and TCT2; the latter is fast and has beyond birthday-bound security, the former is faster and has birthday-bound security.