# Diffie-Hellman Key Exchange explained
**URL:** https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851
**Category:** Lessons Discussion
**Created:** [December 20, 2016, 9:29pm UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851 "2016-12-20T21:29:23Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [December 20, 2016, 9:29pm UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851/1 "2016-12-20T21:29:23Z")
This topic is to discuss the following lesson:
> **[Diffie-Hellman Key Exchange explained](https://networklessons.com/miscellaneous/diffie-hellman-key-exchange-explained)**
>
> The Diffie Hellman (DH) key exchange helps to exchange secure keying material over an insecure network (like the Internet). This video explains it well.
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### Author:  [@Openlearner](https://forum.networklessons.com/u/Openlearner)
#### Post date: [November 15, 2014, 11:11pm UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851/2 "2014-11-15T23:11:09Z")
I have trouble viewing this video.
It says: No palyable sources found. Please advise
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### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [November 17, 2014, 8:12pm UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851/3 "2014-11-17T20:12:23Z")
Just fixed it, it’s working again.
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### Author:  [@joe1664](https://forum.networklessons.com/u/joe1664)
#### Post date: [August 15, 2015, 1:53am UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851/4 "2015-08-15T01:53:22Z")
Rene,
In configuring an ISAKMP Policy, Phase-1, one of the negotiable attributes in the policy is the Diffie-Hellman Group x. Where x is a number. What does the x (number) represent?
Thanks!
Joey
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### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [August 15, 2015, 4:09pm UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851/5 "2015-08-15T16:09:31Z")
Hi Joey,
It’s the DH group number which basically is the strength of the key that we use in the DH key exchange. Higher group numbers are more secure but take longer to calculate:
DH Group 1: 768-bit group
DH Group 2: 1024-bit group
DH Group 5: 1536-bit group
DH Group 14: 2048-bit group
DH Group 15: 3072-bit group
DH Group 19: 256-bit elliptic curve group
DH Group 20: 384-bit elliptic curve group
Rene
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### Author:  [@michmoor](https://forum.networklessons.com/u/michmoor)
#### Post date: [December 10, 2015, 3:50am UTC](https://forum.networklessons.com/t/diffie-hellman-key-exchange-explained/851/6 "2015-12-10T03:50:20Z")
Rene,
Long time since I posted. This is a wonderful video thanks for sharing. I understand it conceptually but what do the red and green locks represent. I understand that the blue key is basically the shared key that will be used to encrypt data in transit.