i used to use this (in my company) to provision OTP secrets. this was before iphone. after provisioning, OTP requests could be offline. thus no worries about se

i used to use this (in my company) to provision OTP secrets. this was before iphone. after provisioning, OTP requests could be offline. thus no worries about sending an otp over sms. of course the secret was itself encrypted via pre-provisioned Key Encrypting Key. or users could manually enter the wrapped otp secret on the off chance the sms didn’t work. it worked for nokia and blackberry so that covered nearly 100%. the article talks about abuse but in my case quite a useful “backdoor”.