Legal journal piece that analyzes the Dual_EC_PRNG backdoor from a US constitutional viewpoint:

Summary: The National Security Agency (NSA) allegedly compensated and coerced tech firms to deceive their clients into using insecure encryption solutions. This piece investigates if any of three arguments dismissed the Fourth Amendment’s stipulation that this must be reasonable. The first posits that a challenge to the encryption backdoor might falter due to a lack of a search or seizure. The paper rejects this, asserting that the Amendment encompasses certain vulnerabilities in addition to the searches and seizures they facilitate, and that the establishment of this vulnerability was itself a search or seizure. The second argument suggests the involvement of tech companies might place this backdoor under the private-search doctrine. The paper critiques this doctrine—particularly its roots in Burdeau v. McDowell­—and contends that, if it ever should be applicable, it ought not to apply in this case. The final argument claims that customers may have forfeited their Fourth Amendment rights through the third-party doctrine. The paper dismisses this on the grounds that customers were unaware of the backdoor and that historical interpretations of the Amendment would not have accepted this situation. The paper concludes that none of these arguments abrogated the Amendment’s reasonableness requirement.