Methods, devices, and systems are provided for approving a transaction through an exchange of presented user contextual approval information and approval decryption. The user contextual approval information is generated by a user during a transaction, cryptographically signed, and provided to a transaction server. The user contextual data uniquely describes the transaction to the user and can be employed to aid a user in approving or validating the transaction in a subsequent approval action. In particular, a transaction may present the contextual approval information to a user in the form of an approval challenge message. The approval challenge message may be sent to a known user device via the transaction server in the form of a text or multi-media message. The user may respond to the message with an approval or denial response.