10. A system for retrieving a document from a document repository, the system comprising: a computing device; and a computer-readable storage medium comprising one or more programming instructions which, when executed by the computing device, cause the computing device to perform a method comprising: receiving a document comprising: a first portion comprising human readable information that is descriptive of a target file in a document repository, and a second portion comprising one or more machine-readable instructions for retrieving the target file, wherein the instructions comprise one or more conditions for retrieval of the target file, wherein the document does not comprise the target file, determining whether to permit access to the target file by: verifying a digital signature on the document, and verifying that the conditions for retrieval are satisfied, in response to permitting access to the target file, automatically retrieving the target file from the document repository, and automatically delivering the target file to a target device.
10. A system for retrieving a document from a document repository, the system comprising: a computing device; and a computer-readable storage medium comprising one or more programming instructions which, when executed by the computing device, cause the computing device to perform a method comprising: receiving a document comprising: a first portion comprising human readable information that is descriptive of a target file in a document repository, and a second portion comprising one or more machine-readable instructions for retrieving the target file, wherein the instructions comprise one or more conditions for retrieval of the target file, wherein the document does not comprise the target file, determining whether to permit access to the target file by: verifying a digital signature on the document, and verifying that the conditions for retrieval are satisfied, in response to permitting access to the target file, automatically retrieving the target file from the document repository, and automatically delivering the target file to a target device. 11. The system of claim 10 , wherein the one or more programming instructions for receiving a document comprise one or more programming instructions for receiving a document wherein the second portion comprises data representative of a location of the target file.