To form a shiftgram of a word, two operations are performed. First, it is enciphered using a shiftcipher, which replaces each letter by the letter n places further on in the alphabet. The result is then transposed to form a word. Howard Bergerson introduced shiftgrams in "Sea-changed Words" (WW 2.1969-24). In "Shiftgrams" (WW 2.1980-22). Tom Pulliam gave more examples and called the operation an n-shift.
"Shiftgrams: Spangled Wordplay,"
Word Ways: Vol. 36
, Article 5.
Available at: https://digitalcommons.butler.edu/wordways/vol36/iss3/5