> if you can hide a backdoor in a simple ARX Feistel block cipher that can be implemented in 100 lines of code, we probably have bigger concerns than these algo

> if you can hide a backdoor in a simple ARX Feistel block cipher that can be implemented in 100 lines of code, we probably have bigger concerns than these algorithms. It wasn't a backdoor, but doesn't this sound a lot like SHA-0? The NSA fixed the mistake and published SHA-1, but they didn't say why. They might as well have designed the cyphers a similar issue and kept it hidden. SIMON and SPECK have been analyzed by the wider cryptography community, but in principle something like the above wouldn't be surprising from the NSA...