Several encryption proposals for DNS have been presented since 2016, but their adoption was not comprehensively studied yet. This research measured the current adoption of DoH (DNS over HTTPS), DoT (DNS over TLS), and DoQ (DNS over QUIC) for five months at the beginning of 2021 by three different organizations with global coverage. By comparing the total values, amount of requests per user, and the seasonality of the traffic, it was possible to obtain the current adoption trends. Moreover, we actively scanned the Internet for still-unknown working DoH servers and we compared them with a novel curated list of well-known DoH servers. We conclude that despite growing in 2020, during the first five months of 2021 there was statistically significant evidence that the average amount of Internet traffic for DoH, DoT and DoQ remained stationary. However, we found that the amount of, still unknown and ready to use, DoH servers grew 4 times. These measurements suggest that even though the amount of encrypted DNS is currently not growing, there may probably be more connections soon to those unknown DoH servers for benign and malicious purposes.

翻译：自2016年以来,对DNS的加密建议已经提出,但是其采用还没有经过全面研究。这一研究测量了2021年初三个不同组织采用DoH(HTPS上的DNS)、DT(TLS上的DNS)和DQ(QuIC上的DNS)的时间为5个月,覆盖全球的3个不同组织2021年年初,对DH(DNS)和DQ(QUIC上的DNS)目前采用的时间为5个月。通过比较总价值、每个用户请求的数量以及交通的季节性,我们有可能获得目前的采用趋势。此外,我们积极扫描互联网,为仍然未知的工作 DH服务器,并将它们与已知的DoH服务器的新编目录进行比较。我们的结论是,尽管在2021年头5个月中,尽管有所增长,但有统计上的重要证据表明,DoH、DoT和DoQ的互联网平均流量仍然是固定不变的。然而,我们发现,DoH服务器的数量仍然未知而且随时可以使用,增加了4倍。这些测量表明,尽管加密的DNS数量目前没有增加,但可能很快会与那些未知的DoH服务器用于友好和恶意目的。