There are two alternatives to ISMACryp, SRTP and IPsec, that can also be used to provide service and content protection. The difference between the three is at what level encryption is done. Whereas ISMACryp encrypts MPEG-4 access units (that are in the RTP payload), SRTP encrypts the whole RTP payload, and IPsec encrypts packets at network level.

The ISMACryp specification does not mandate a cipher but AES in Counter Mode, the default encryption and authentication transform in the specification, is the de facto cipher used by ISMACryp implementations.

See also

• RTP
• SRTP
• IPsec

Notes

External links

• ISMA Encryption and Authentication Version 1.1
• DVB-H handheld video content protection with ISMA Encryption