After a wintertime journey of six months from St. Petersburg to The Hague, sixteen-year-old John Quincy Adams arrived on 21 April 1783 carrying a packet of sensitive papers. The packet included a letter to John Adams from U.S. Minister to Russia Francis Dana dated 15 October 26 October N.S. 1782, and it probably also included this cipher, which is dated three days later. John Quincy reported to his father that Dana attached great importance to the papers, “which he enjoined me to deliver into your hands myself” (JQA, Diary , 1:153–175; AFC , 5:130).

John Adams found the use of ciphers to be cumbersome and frustrating. A year earlier he had lamented to Dana that he had been unable to read a coded letter from James Lovell. “I have Letters from the President and from Lovell—the last unintelligible—in Cyphers—but inexplicable by his own Cypher—some dismal Ditty about my Letters of 26th. July—I know not what” (vol. 11:195–196).

The cipher Dana offered in October 1782 was relatively easy to use, yet difficult to crack because it assigned three revolving numerical stand-ins to each letter of the alphabet, as well as to each of eighty key names and terms. Most words were rendered as a series of numbers from 1 to 27, which the reader would match to individual letters and the ampersand. When any number higher than 27 appeared, however, the reader was to decode the whole word it represented and then shift to the next set of revolving numerical stand-ins. In that way, Dana's cipher made use of the best features of codes of the era (Ralph E. Weber, United States Diplomatic Codes and Ciphers 1775–1938, Chicago, 1979, p. 31, 36, 560–563).