User's Manual

The following table highlights the two cipher suites that are used and their related
parameters.
Table 85: SRTP properties
Parameter AES_CM_128_HMA
C_SHA1_80
AES_CM_128_HMAC_SHA1_32
Master key
length
128 bits 128 bits
Master salt
length
112 bits 112 bits
SRTP lifetime 2^48 packets 2^48 packets
SRTCP lifetime 2^31 packets 2^31 packets
Cipher AES Counter Mode AES Counter Mode
Encryption key 128 bits 128 bits
MAC HMAC-SHA1 HMAC-SHA1
SRTP auth. tag 80 bits 32 bits
SRTCP auth. tag 80 bits 80 bits
SRTP auth. key
len.
160 bits 160 bits
SRTCP auth. key
len.
160 bits 160 bits
Call security is identified by the presence of the security icon present during an active call, as
shown in the following example.
The presence of the security icon is the only visible indication that the media path is encrypted.
The presence of this icon depends on whether the IP Deskphone has been configured to
support SRTP or not and is visible when the IP Deskphone is not in the idle screen.
Security
286 SIP Software for Avaya 1200 Series IP Deskphones-Administration September 2013
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