About the ISTC Structure and Syntax of the ISTC Basic structure and syntax

An ISTC consists of 16 numbers and/or letters. These are “hexadecimal digits”, which may be any of the Arabic numerals 0 to 9 and the Latin letters A to F.

While no “meaning” should be inferred from the digits of an ISTC, they are constructed from the following parts, starting from the left:
  • Registration element – This is used by the registration agency for administrative purposes and consists of 3 hexadecimal digits;
  • Year element – This is 4 digits long and represents the year in which the ISTC was registered (it does not relate to the year in which the work was produced or first published);
  • Work element – This consists of 8 hexadecimal digits. It is assigned automatically by the central ISTC registration system after a metadata record has been submitted for registration and the system has verified that the record is unique;
  • Check digit – This is a single hexadecimal digit, automatically generated by the ISTC registration system. It is calculated in accordance with ISO/IEC 7064 using MOD 16-3.
When an ISTC is displayed it should be preceded by the letters “ISTC”, with a hyphen or space between each element, as shown in the following examples:


ISTC 0A9 2002 12B4A105 7
ISTC 0A9-2002-12B4A105-7