Masked Dispatches: Cryptograms and Cryptology in American History, 1775-1900

Introduction

	But why a cypher between us . . . there may be matters merely personal to ourselves, and which require the cover of a cypher more than those of any other character. This last purpose, and others which we cannot for[e]see may render it convenient & advantageous to have at hand a mask for whatever may need it.
	--President Thomas Jefferson to Robert Livingston, 1802

Almost two months after the declaration of war against Spain in 1898, the following coded dispatch, cabled to the secretary of state from the American minister in Madrid, arrived at the White House in Washington, D.C.:

This coded telegram to the newly installed secretary of ...