Commit 79c8e1
2025-02-27 12:31:38 Samuli Seppänen: Add DUHK attack page| /dev/null .. Security Announcements/DUHKattack.md | |
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| + | # DUHK attack and OpenVPN |
| + | |
| + | ## Background |
| + | October 24, 2017 Shaanan Cohney, Nadia Heninger and Matthew D. Green released [Practical state recovery attacks against legacy RNG implementations](https://duhkattack.com/paper.pdf) (PDF) which have been known as the DUHK attack: [Don't Use Hard-coded Keys](https://duhkattack.com/). This relates in particular to a Random Number Generator (RNG) algorithm known as *ANSI X9.31 RNG*. |
| + | |
| + | The ANSI X9.31 RNG has been deprecated as part of the FIPS specification as of January 2016 and is further discouraged elsewhere too. |
| + | |
| + | ## How is OpenVPN affected? |
| + | |
| + | OpenVPN is ***not*** affected by DUHK. All random number generation in OpenVPN is based upon the SSL/TLS libraries and, to our knowledge, neither OpenSSL nor mbed TLS depends on the ANSI X9.31 RNG algorithm. Further, OpenVPN does not use or deploy any hard-coded keys or seeds for the RNG. And both OpenSSL and mbed TLS libraries implements re-seeding of the RNG at regular intervals. |