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

Masked Dispatches: Cryptograms and Cryptology in American History, 1775-1900 is a National Security Agency history of American cryptology before the twentieth century, written by Ralph E. Weber with a foreword by David W. Gaddy. It is Volume 1 of the NSA Center for Cryptologic History's United States Cryptologic History, Series I: Pre-World War I, first published in 1993 and later reissued, including a third edition in 2013.

The 227-page volume traces American cryptography from the Continental Congress's United Colonies' Cipher through the coded diplomatic and Civil War-era correspondence of the nineteenth century, drawing on the papers of figures including James Lovell and State Department codebook author John Haswell. It covers the period before wireless communication, when codes and ciphers moved by messenger and handwritten correspondence rather than electronic transmission.

Weber was professor emeritus of history at Marquette University and worked on deciphering coded material in the papers of Presidents John Adams and Woodrow Wilson. Gaddy, who contributed the foreword, was a charter member of the Senior Cryptologic Executive Service. The book is distributed free by the NSA's Center for Cryptologic History and is available as a PDF from the agency.