The NSA recently released SIMON and SPECK light weight block ciphers. Although initial spec release did not have much of cryptanalysis details, two works later appeared providing the cryptanalysis for the same SIMON and SPECK.
But how should we interpret those results? Are they considered good or bad?
For example:
- Attack complexity of key-recovery attack for SPECK32/64 is it requires $2^{29}$ plain texts…
Is that good or bad? - Rectangle attacks need $2^{30}$ plain texts…
Is this good or bad?