1. A remote command execution system, providing authentication, comprising: (a) an input channel configured to receive at least one electronic communication comprising an email from a user over a first information channel using a first channel communication interface; (b) a processor configured to: (i) generate a challenge communication using a second information channel distinct from the first information channel comprising a message containing a matrix of information, said matrix comprising a plurality of possible authentication codes comprising at least one valid authentication code and at least one invalid authentication code, wherein a valid authentication code is selected based on at least information not communicated within the same message, and using a second channel communication interface, wherein the first and second channel communication interfaces are different, selectively dependent on at least a portion of information of the at least one electronic communication; (ii) receive a selective response to the challenge communication through an authorized channel, containing authentication information communicated by a voice, dependent on a secret and information selectively derived from the challenge communication, wherein the secret is cryptographically protected against eavesdropping, the selective response being generated based on at least one pre-shared key, processed using a manually implemented algorithm by a user to produce an authentication response; (iii) authenticate the user based on the authentication response, a digital signature, information contained in an email header of the received email, a time-dependent function of a time delay of the received email, an address of the authorized channel, and a password derived from an algorithm executed by the processor, communicated within an email communication to a remote location; and (iv) define a command from a portion of the electronic communication having a command information type; and (c) an output channel configured to pass the defined command to an automated command processor, for automatic execution.