Probably very few or none of them, cryptography getting broken is common. There is no hint that this weakness was introduced on purpose. Now, did the NSA find

Probably very few or none of them, cryptography getting broken is common. There is no hint that this weakness was introduced on purpose. Now, did the NSA find the attack on their own, kept it secret and hoped for standardization? One can only speculate. Also, the NSA does not always try to backdoor everything like they did with DUAL_EC_DRBG. For instance, they modified the S-box of DES during the NIST standardization and refused to elaborate on why. The reason was later found, as people invented differential cryptanalysis and found that the NSA-modified S-box was resistant to it, when the original S-box was not: the NSA actually made DES stronger on purpose. https://arstechnica.com/information-technology/2013/09/the-nsas-work-to-make-crypto-worse-and-better/ https://arstechnica.com/information-technology/2013/09/the-n...