[SC-L] Another example of the futility of hardwareless 2 factor authentication

Consider the following attempt at el-cheapo (no hardware) authentication: It is possible to imagine an authentication scheme that wants to use something like a certificate with signing, encrypting random nonces etc., to verify that someone agrees to some transaction(s). If the certificate is

Re: [SC-L] Another example of the futility of hardwareless 2 factor authentication

Consider the following attempt at el-cheapo (no hardware) authentication: [...] It is possible to imagine an authentication scheme that wants to use something like a certificate with signing, encrypting random nonces etc., to verify that someone agrees to some transaction(s). If the