Phone encryption questions...

Answered Question
Jun 8th, 2007

Can someone explain to me what the difference is between TLS and SRTP in the context of phone-to-phone encryption? Does TLS encrypt the RTP stream? What about when using SIP phones?

Thanks,

Chris

I have this problem too.
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Correct Answer by thisisshanky about 9 years 5 months ago

Chris, You are almost there. TLS is the protocol used to encrypt RTP stream. Once RTP is encrypted, its called SRTP. TLS stands for transport layer security. TLS provides Integrity, Authentication and Encryption. TLS uses certificates. When a phone is configured from Non-secure to secure mode, a certificate is generated for that phone and installed on the phone. These are called LSCs.

These certificates are used for encrypting the signalling and voice payload. More details can be found in callmanager security guide.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a00806b23fc.html

HTH

Sankar

PS: please remember to rate posts!

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Correct Answer
thisisshanky Fri, 06/08/2007 - 08:17

Chris, You are almost there. TLS is the protocol used to encrypt RTP stream. Once RTP is encrypted, its called SRTP. TLS stands for transport layer security. TLS provides Integrity, Authentication and Encryption. TLS uses certificates. When a phone is configured from Non-secure to secure mode, a certificate is generated for that phone and installed on the phone. These are called LSCs.

These certificates are used for encrypting the signalling and voice payload. More details can be found in callmanager security guide.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a00806b23fc.html

HTH

Sankar

PS: please remember to rate posts!

chris.damore Fri, 06/08/2007 - 08:21

Sankar

SIP phones support encryption the same way as SCCP phones, correct?

Thanks,

Chris

ngss Sun, 06/10/2007 - 06:32

Hi,

TLS is the protocol used to encrypt RTP stream

[SS] This is not corerct. TLS is for Signalling encryption.(Refer below)

SRTP for media encryption.

Thanks

SS

========

Table 1.2

Signaling Authentication/Encryption

TLS Mode: authenticated or encrypted

IPSec [authentication header, encryption (ESP), or both]

TLS Mode: authenticated or encrypted mode (SIP trunk only)

Media Encryption

SRTP

SRTP

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