15. A system for associating geographic information with textual information, comprising: a processor, and a non-transitory computer-readable medium including instructions configured to cause the processor to carry out the steps of: receiving, from a first computer, a request for a digital map of a specified geographic region; identifying a spatial key associated with the geographic region; encrypting the identified spatial key; embedding the encrypted spatial key into the requested digital map; returning, to the first computer, the requested digital map including the encrypted spatial key; receiving, from a second computer, a request to decrypt the encrypted spatial key, the encrypted spatial key extracted by the second computer from the digital map; decrypting the spatial key; and returning, to the second computer, the decrypted spatial key.
15. A system for associating geographic information with textual information, comprising: a processor, and a non-transitory computer-readable medium including instructions configured to cause the processor to carry out the steps of: receiving, from a first computer, a request for a digital map of a specified geographic region; identifying a spatial key associated with the geographic region; encrypting the identified spatial key; embedding the encrypted spatial key into the requested digital map; returning, to the first computer, the requested digital map including the encrypted spatial key; receiving, from a second computer, a request to decrypt the encrypted spatial key, the encrypted spatial key extracted by the second computer from the digital map; decrypting the spatial key; and returning, to the second computer, the decrypted spatial key. 16. The system of claim 15 wherein the returned digital map is a bitmap image and the spatial key and bounding box are encoded in red, green and blue values of the bitmap image.