Cell phone maker Motorola Inc. said Thursday it had agreed to buy SecureM LLC, a developer of digital rights management software approved by movie studios and TV broadcasters.

Terms of the agreement were not disclosed.

The transaction is expected to close by the end of March.

SecureM will become part of Motorola's Home & Networks Mobility business, helping secure the distribution of digital entertainment over multiple platforms and devices, including set-top boxes, wireless handsets, computers and portable media players.

Motorola shares rose 6 cents at $8.03 in Thursday afternoon trading.