This foot note contained in document PJA09d173
2. Lovell's cipher consisted of an alphabetical square composed of 27 columns and 27 numbered rows, the 27th character being the ampersand. To encipher a letter one would take letters from a key word, and read down the corresponding columns to the desired letter and substitute the number of the row for the letter. In JA's case, since he and Lovell had stayed with the Richard Cranch family on their way to Baltimore in 1777, the letters were “C” and “R” from the key word “CRANCH.” According to Lovell's instructions, JA would first read down the “C” column to encipher the first letter of a passage and then read down the “R” column to encipher the second letter. He would then alternate between the “C” and the “R” columns until the encipherment of the passage was completed. Each new passage would begin with the “C” column. To decipher a passage the process was reversed.
Cite web page as: Founding Families: Digital Editions of the Papers of the Winthrops and the Adamses, ed.C. James Taylor. Boston: Massachusetts Historical Society, 2007.