Preston Kavanagh, «The Jehoiachin Code in Scripture’s Priestly Benediction», Vol. 88 (2007) 234-244
Coding in the OT is plausible because of the Exile’s profusion of scripture, the Diaspora’s need for secure communication, and the ancient world’s widespread use of cryptography. A code exists in Num 6,24-26 that uses one letter per text word, from words spaced at regular intervals, with letters used in any sequence. Coding of Jehoiachin’s name in the MT’s Priestly Benediction establishes the mid-sixth century B.C.E. as the earliest possible time for the Ketef Hinnom amulets. Moreover, since the Ketef Hinnom scribe appears to have understood nothing of the benediction’s Jehoiachin coding, the amulets could be considerably later than mid-sixth century.