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Phone encryption questions...

chris.damore
Level 1
Level 1

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

1 Accepted Solution

Accepted Solutions

thisisshanky
Level 11
Level 11

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!

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

View solution in original post

4 Replies 4

thisisshanky
Level 11
Level 11

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!

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

Sankar

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

Thanks,

Chris

It works a little bit different with SIP phones, but basically the idea is the same. Signalling and media are encrypted. Check this link for more details.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a0080646eac.html#wp1067385

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

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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