ISMACryp

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ISMACryp is a security system for protecting MPEG-4 video delivered over RTP. It was created by the Internet Streaming Media Alliance (ISMA) to provide both encryption and authentication for streaming media.

Two main versions exist:

- ISMA Encryption and Authentication, Version 1.1 (published September 15, 2006): Provides encryption and authentication services for MPEG-4 over RTP.

- ISMA Encryption and Authentication, Version 2.0 (published November 15, 2007): Adds a full content encryption and integrity framework, a formal RTP payload format, and a file format for pre-encrypted content. It extends the ISO base media file format (used by MP4) with ISMACryp-specific features. Annex F offers guidelines on using ISMACryp with the Open Mobile Alliance DRM (OMA DRM) v2. The Packetized OMA DRM content format is closely based on ISMACryp.

How ISMACryp compares to other protections:

- SRTP and IPsec can also protect RTP streams, but they work at different levels. ISMACryp specifically encrypts MPEG-4 access units inside the RTP payload, while SRTP encrypts the entire RTP payload, and IPsec protects data at the IP layer.

In short, ISMACryp provides encryption and authentication tailored for MPEG-4 content in streaming media, with versions that broaden support for formats, DRM integration, and interoperability with MP4-based content.