According to SanDisk, it can't be used on other devices and also effectively stops content being transferred to other users.
The MicroSD card could be managed and even refreshed with new content over the air, said SanDisk spokesman Mike Wong.
These cards could help to make a particular handset or plan more attractive to a subscriber by offering songs, movies, maps for GPS (Global Positioning System) navigation or applications. However, locking the card will ensure consumers couldn't use the content elsewhere.
Users would be able to put their own content on the unused part of the card. SanDisk did not say how big the cards would be, but it currently sells MicroSD cards as large as 16GB.
Consumers are increasingly turning to their mobile phones for entertainment, and mobile-phone-based navigation is an emerging trend. But the technology SanDisk and LG demonstrated may not deliver content the way today's consumers want to receive it.
In the demonstration, the MicroSD card used the SIM card in an LG KC910 Renoir handset to authenticate the user. If the user inserted the MicroSD card in a friend's phone, or unlocked the Renoir handset from the carrier that sold the MicroSD card and then put in a SIM card from another operator, the content on it wouldn't be accessible.
The key to the system is the MicroSD card, which fits into a standard slot, Wong said. It uses the Open Mobile Alliance standard 'OMA smart card web server' that would allow carriers to control the card via IP. It wasn't immediately clear whether the technology could be adapted to work with Code Division Multiple Access (CDMA), which doesn't use SIM cards, he said.
SanDisk is talking with mobile operators and hopes to announce deals with some at the Mobile World Congress next month, Wong said.
However, analysts believe the technology is emerging at a bad time. Consumers are used to having digital content, especially music, available on any device they choose to put it on, said Charles Golvin of Forrester Research. And the trend is moving toward content distribution over the carriers' increasingly fast data networks instead of offline, he said.
"I don't see this as becoming a really significant distribution mechanism," Golvin said.
With content that is specifically for the phone, such as maps for use with a navigation application, SanDisk's approach might make sense, said In-Stat analyst Allen Nogee. But in the wake of recent events such as Apple's move to sell songs on iTunes without DRM (digital rights management), it isn't likely to be a big draw for other types of content, he said.
See also: SanDisk launches laptop SSDs