I have read the paper for speck. The actaully cipher is very unlikely to have been back doored. The only isue I have is the mode of operation with 64 bit blocks

I have read the paper for speck. The actaully cipher is very unlikely to have been back doored. The only isue I have is the mode of operation with 64 bit blocks and short keys. In my opinion just ignore the 64bit variants and keys less than 96 bits in lenth. The cipher is rather simple so hiding a back door would require a method of attack not known to anyone publicly. Theres just too small of a surface, and uses pretty stanard operations.