Jörg Walter has created a new implementation of Threefish-256 and Skein-256 for the Atmel AVR 8-bit microcontrollers. His implementation is very fast:
- Threefish in 8800 cycles
- Skein in 18500 cycles for short messages
- 290 cycles per byte for long messages
- PRNG in 1250 cycles per byte
His implementation is called Fhreefish, available at this link.