- Length of key in bits – 16 bit value from 1 to 65535
- Key information identifier – 8 bit value that indicates the meaning of the values in the value list (see
Table 1) - Granularity field – 24 bit value indicating the granularity with which the key information changes
- Value list – value of representing the changing list of key information
Table 1: JPSEC Key Information Identifiers
| Identifier | Key Information |
|---|---|
| 0 | Reserved |
| 1 | X.509 Certificate |
| 2 | URI for certificate or secret key |
| All other values are reserved for ISO use |
When the key information identifier is URI for certificate or secret key then this defines the values in the Value
List. When the X.509 Certificate is selected as the Key Information Identifier then the X.509 certificate
template is used as the value list. The first part of the X.509 template is the encoding rule field that is 8 bits
long (0…255), the second field holds the length of the X.509 certificate and is 16 bits long (1…65535) and the
final field holds the actual X.509 certificate which is of variable length. There are only two encoding rules defined
in the JPSEC standard, Basic Encoding Rule (BER) and Distinguished Encoding Rule (DER).
Further information available here:
JPSEC Tool Decryption Template
JPSEC Tool Authentication Template
JPSEC Registration Authority (RA)
JPSEC Standards available here:
Joint Photographic Experts Group (JPEG) Part 8 – JPSEC: Secure JPEG 2000 Final Committee Draft
ISO/IEC 15444-8:2007 – Information technology — JPEG 2000 image coding system: Secure JPEG 2000
T.807 (05/06) – Information technology — JPEG 2000 image coding system: Secure JPEG 2000