Musical cryptogram

A musical cryptogram is a cryptogrammatic sequence of musical symbols which can be taken to refer to an extra-musical text by some 'logical' relationship, usually between note names and letters. The most common and best known examples result from composers using musically translated versions of their own or their friends' names (or initials) as themes or motifs in their compositions, with an early and commonly known example being the BACH sequence used by the composer. These are not really rigorous cipher algorithms in the formal sense, but more like musical monograms or labels using initials. The methods used historically by composers were either too incomplete (i.e., did not include all of the letters of the alphabet) or too simplistic to meaningfully encrypt long text messages.