It was first described by Frank Miller in 1882 and re-invented by Gilbert Vernam in 1917, who also patented the cipher in 1919. The original version of the Vernam cipher had a cryptographical weakness because the bits on the key tape were reused after having been used once. The one-time use of the key tape was introduced later by Joseph Mauborgne who conjectured that cryptanalysis would be impossible if the key bits were completely random and never reused [192]. About 25 years later, Claude Shannon, was able to show mathematically that the one-time pad is indeed perfectly secret.
