Specifications

F-5
Cisco Internet Streamer CDS 2.0-2.2 API Guide
OL-14319-03
Appendix F URL Signing and Validation
Understanding the Signing Procedure
The following two devices are synchronized:
• Device 1:
– Local Time: 11:00:59 AM, October 12, 2008
– Time Zone: PST
• Device 2:
– Local Time: 2:00:59 PM, October 12, 2008
– Time Zone: EST
Understanding the Signing Procedure
To customize the URL signing script for your portal, or to write your own signing application in the
platform and language of your choice, and still be able to validate URLs within the CDS, follow the steps
explained in this section.
The URL signing script performs these steps when processing an unsigned URL:
1. Checks if the URL already contains a query string.
If the URL does not contain a query string, appends a question mark (?).
If the URL does contain a query string, appends an ampersand (&).
2. Appends the string IS=0. This string is for legacy support with some CDS components that use both
internal (within CDS) and external (portal) signing mechanisms.
3. Appends the string &ET=.
4. Gets the current time in seconds since epoch (as an integer). Adds the expiry time in seconds as an
integer and appends this integer.
5. Appends the string &CIP=.
6. Appends the requesting client IP address, using dotted decimal format.
7. Appends the string &KO=.
8. Appends the key ID owner corresponding to the key being used.
9. Appends the string &KN=.
10. Appends the key ID number corresponding to the key being used.
11. Appends the string &US=.
12. Stores this as url2; for example:
“rtsp://cisco.com/content/CiscoCDS.mov?IS=0&ET=1209422976&CIP=171.71.50.123&KO=
1&KN=2&US=”
13. Generates an MD5 hash of the key being used.
14. Updates the generated hash with url2.
15. Converts the hash to its equivalent human readable hex digest; for example:
f08b56f46075813e44b2d4888628a471
16. Appends the hex digest to url2. The URL signing is complete.