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Its underlying library, OpenSSL, had all kinds of issues. OpenVPN itself allowed many configurations of varying strength and weakness. OpenVPN users could set t

Its underlying library, OpenSSL, had all kinds of issues. OpenVPN itself allowed many configurations of varying strength and weakness. OpenVPN users could set their own security up to fail while getting false assurances because they were "using a VPN." It was also a large, complex codebase which simultaneously increases number of incidental vulnerabilities and the work necessary for defenders to prevent/find all of them. When one government adopted it, the security firm had to do a lot of hardening (OpenVPN-NL) to reduce its risks. That shouldn't be necessary in a VPN. On contrary, WireGuard started with strongest crypto it could making it default. There's also the protocol and implementation correctness to consider. WireGuard was formally-verified in Tamarin, kept small on purpose to reduce errors, carefully coded by project author focusing on security more than feature bloat, and reviewed with positive results by other security-focused coders. It's better assurance than OpenVPN across the board. Even if I didn't have those details, the fact that WireGuard is usable out of the box in Linux while OpenVPN needs to be hardened and extra-carefully configured first would already tell me what I need to know. Use WireGuard, not OpenVPN, if you're able to.

gshulegaard 8y ago
Just throwing it out there, but WireGuard does more than just make strong crypto "default". Instead of separating, say, transport from encryption (transformation) they tightly couple them. It's intentionally limiting this flexibility for the sake of performance and administration simplicity...in their own words: > It intentionally lacks cipher and protocol agility. If holes are found in the underlying primitives, all endpoints will be required to update. (https://www.wireguard.com/papers/wireguard.pdf https://www.wireguard.com/papers/wireguard.pdf) Just skimming their whitepaper it seems this is done to cram everything into Layer 3 which has administrative and performance benefits. But comes with a significant tradeoff to flexibility. They follow up that statement with something that slightly confuses me: > As shown by the continuing torrent of SSL/TLS vulnerabilities, cipher agility increases complexity monumentally. But the general sense I am getting is WireGuard is strongly opinionated and limited...and one way of spinning that is less vulnerable to user error. Personally, I have trouble equating that to meaning WireGuard is more secure. For similar reasons I have trouble equating OpenVPN configuration to "requiring hardening". That said WireGuard's approach and lower layer, like IPsec, has some serious performance advantages over OpenVPN. Their whitepaper also seems to indicate that it performs better the IPsec, but I would have to see more benchmarks from other sources before making a definitive conclusion on that. Judging from this article and the comments in this overall thread though, it appears that WireGuard has some zealous (perhaps a bit over-zealous) evangelists though.
- tptacek 8y ago
  There's a growing consensus among cryptography engineers (by no means all of them, but a pretty significant set of them) that cryptographic agility in protocols is a design mistake. That doesn't mean that we should assume modern primitives and constructions are unbreakable (though the trend has been for protocol designers to seriously overestimate the likelihood of _any_ primitive being broken). What it means is that instead of designing and implementing elaborate handshake mechanisms, which inevitably succumb to downgrade attack bugs or, often, worse things, we should version entire protocols. So obviously, if the ChaPoly stack is broken at some point, people will need to update WireGuard (just like they update OpenVPN when TLS bugs are discovered). But they protocol doesn't need to account for anything more than the fact that it might someday be replaced with a different protocol using different primitives. The "agility" protocol designers are looking for has probably, historically, been implemented at the wrong layer. As usual, the closer something is to policy or prognostication, the further up the stack it should go. TLS bakes this stuff into the transport layer, which has hamstrung us and, ironically, not actually done much to protect us against vulnerabilities. WireGuard makes a different, better decision. There's no tradeoff here; this decision is by itself a reason to adopt WireGuard.
  - JoachimS 8y ago
    "There's a growing consensus among cryptography engineers (by no means all of them, but a pretty significant set of them) that cryptographic agility in protocols is a design mistake." And yet in 2018 we have proposals like this: https://tools.ietf.org/html/draft-ietf-ntp-using-nts-for-ntp-11 https://tools.ietf.org/html/draft-ietf-ntp-using-nts-for-ntp... To me it looks enormously over engineered with options, versions and flexibility everywhere.
    - tptacek 8y ago
      There's an even growinger consensus among cryptographers that IETF cryptography standardization is a disaster, even with smart people chairing the WGs. It's just a bad process.
- woah 8y ago

gshulegaard 8y ago

Just throwing it out there, but WireGuard does more than just make strong crypto "default". Instead of separating, say, transport from encryption (transformation) they tightly couple them. It's intentionally limiting this flexibility for the sake of performance and administration simplicity...in their own words: > It intentionally lacks cipher and protocol agility. If holes are found in the underlying primitives, all endpoints will be required to update. (https://www.wireguard.com/papers/wireguard.pdf https://www.wireguard.com/papers/wireguard.pdf) Just skimming their whitepaper it seems this is done to cram everything into Layer 3 which has administrative and performance benefits. But comes with a significant tradeoff to flexibility. They follow up that statement with something that slightly confuses me: > As shown by the continuing torrent of SSL/TLS vulnerabilities, cipher agility increases complexity monumentally. But the general sense I am getting is WireGuard is strongly opinionated and limited...and one way of spinning that is less vulnerable to user error. Personally, I have trouble equating that to meaning WireGuard is more secure. For similar reasons I have trouble equating OpenVPN configuration to "requiring hardening". That said WireGuard's approach and lower layer, like IPsec, has some serious performance advantages over OpenVPN. Their whitepaper also seems to indicate that it performs better the IPsec, but I would have to see more benchmarks from other sources before making a definitive conclusion on that. Judging from this article and the comments in this overall thread though, it appears that WireGuard has some zealous (perhaps a bit over-zealous) evangelists though.

tptacek 8y ago
There's a growing consensus among cryptography engineers (by no means all of them, but a pretty significant set of them) that cryptographic agility in protocols is a design mistake. That doesn't mean that we should assume modern primitives and constructions are unbreakable (though the trend has been for protocol designers to seriously overestimate the likelihood of _any_ primitive being broken). What it means is that instead of designing and implementing elaborate handshake mechanisms, which inevitably succumb to downgrade attack bugs or, often, worse things, we should version entire protocols. So obviously, if the ChaPoly stack is broken at some point, people will need to update WireGuard (just like they update OpenVPN when TLS bugs are discovered). But they protocol doesn't need to account for anything more than the fact that it might someday be replaced with a different protocol using different primitives. The "agility" protocol designers are looking for has probably, historically, been implemented at the wrong layer. As usual, the closer something is to policy or prognostication, the further up the stack it should go. TLS bakes this stuff into the transport layer, which has hamstrung us and, ironically, not actually done much to protect us against vulnerabilities. WireGuard makes a different, better decision. There's no tradeoff here; this decision is by itself a reason to adopt WireGuard.
- JoachimS 8y ago
  "There's a growing consensus among cryptography engineers (by no means all of them, but a pretty significant set of them) that cryptographic agility in protocols is a design mistake." And yet in 2018 we have proposals like this: https://tools.ietf.org/html/draft-ietf-ntp-using-nts-for-ntp-11 https://tools.ietf.org/html/draft-ietf-ntp-using-nts-for-ntp... To me it looks enormously over engineered with options, versions and flexibility everywhere.
  - tptacek 8y ago
    There's an even growinger consensus among cryptographers that IETF cryptography standardization is a disaster, even with smart people chairing the WGs. It's just a bad process.
woah 8y ago