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8.2. Key Management parameters

8.2. Key Management parameters

The table below lists all SRTP parameters that key management can supply. For reference, it also provides a summary of the default and mandatory-to-support values for an SRTP implementation as described in Section 5.

ParameterMandatory-to-supportDefault
SRTP and SRTCP encr transf.
(Other possible values: AES_f8)
AES_CM, NULLAES_CM
SRTP and SRTCP auth transf.HMAC-SHA1HMAC-SHA1
SRTP and SRTCP auth params:
n_tag (tag length)
SRTP prefix_length
80
0
80
0
Key derivation PRFAES_CMAES_CM
Key material params
(for each master key):
master key length
n_e (encr session key length)
n_a (auth session key length)
master salt key
length of the master salt
n_s (session salt key length)
key derivation rate
128
128
160

112
112
0
128
128
160

112
112
0
key lifetime
SRTP-packets-max-lifetime
SRTCP-packets-max-lifetime
from-to-lifetime <From, To>
2^48
2^31
2^48
2^31
MKI indicator
length of the MKI
value of the MKI
0
0
0
0
Crypto context index params:
SSRC value
ROC
SEQ
SRTCP Index
Transport address
Port number
Relation to other RTP profiles:
sender's order between FEC and SRTP
(see Section 10)
FEC-SRTPFEC-SRTP