A musical cryptogram is a sequence of pitches that utilizes the relationship between the note names and letters of the alphabet to spell out words. Most often, it has been used by composers to secretly embed their own name or initials into a piece of music. A lot of composers use the German spelling for the notes so that in addition to the musical letters A-B-C-D-E-F-G, it also includes the letters H and S on chromatic pitches.
Johann Sebastian Bach was one of the first to cipher his name, B-A-C-H (B-flat, A, C, B-natural), into his music. Bach uses his name as the final fugue subject in the last Contrapunctus of The Art of Fugue and the motive also appears in the Sinfonia No. 9 in F Minor. Many composers in the 19th and 20th centuries also paid homage to J.S. Bach by using the B-A-C-H motive in their own music too.
The Russian composer Dimitri Shostakovich also loved to put his own name into his music. He used the letters D-S-C-H (D, E-flat, C, B-natural) to spell it. The motif occurs in many works including the 8th, 10th and 15th Symphonies, the Violin Concerto No. 1 in A minor, the Cello Concerto No. 1 in E-flat major, and most notably the String Quartet No. 8 in C minor where the motive appears prominently in every single movement.
Many other composers enjoyed the cryptic game of embedding their names in their music too: Robert Schumann (S-C-H-A), Alban Berg (A-B), and Arnold Schoenberg (A-S-C-H-B-E-G) amongst others. So next time you’re in the symphony hall, you may just be hearing an encrypted code!