Re: [Ccrtp-devel] how to generate keystream segment for SRTP header

[Werner Dittmann]

Do you implement SRTP for this RTP stack? We already have SRTP
avaliable since some years. If you like to implement SRTP for some
other project maybe you can have a look in the source files to
see how this is implemented.

Best Regards,
Werner

Yogesh Devidas Patil schrieb:
> Hi
> I am implementing SRTP and have  little confusion about it.
> 
> as per my understanding of SRTP RFC3711,
> Initialization vector(IV) is generated as
> 
> IV = (salt_key << 16) XOR (SSRC << 64) XOR (packet_index << 16)
> 
> and  keystream segment (required for AES ICM ) is generated as
> 
> Keystream_seg = E(k,IV) where k=Session key
> i.e Keystream_seg = k XOR IV
> 
> is my understanding correct wrt SRTP standard??
> 
> Wherein AES ICM RFC3686, keystream segment consists
> keystream_seg = NONCE || IV || Counter where Counter advances from initial 
> val=0.
> 
> I mean how to relate these keystream_seg forming units in AES 
> ICM(NONCE,IV,Counter) with SRTP header fields & fields computed from them??
> 
> Second, how should i generate Master Key on sender side??And how to derive 
> session keys from Master Key??
> 
> Thanks in advance!!
> 
> 
> Regards
> Yogesh Patil
> 
> A R I C E N T
> 
> "DISCLAIMER: This message is proprietary to Aricent and is intended solely 
> for the use of the individual to whom it is addressed. It may contain 
> privileged or confidential information and should not be circulated or used 
> for any purpose other than for what it is intended. If you have received this 
> message in error,please notify the originator immediately. If you are not the 
> intended recipient, you are notified that you are strictly prohibited from 
> using, copying, altering, or disclosing the contents of this message. Aricent 
> accepts no responsibility for loss or damage arising from the use of the 
> information transmitted by this email including damage from virus."
> 
> 
> _______________________________________________
> Ccrtp-devel mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/ccrtp-devel
>