Most popular variants of the header value (we only show this when there's just a bunch of variants):

Announces a list of X.509 certificate hashes that are allowed to appear in the website's TLS certification path (HTTP Public Key Pinning or HPKP). This prevents malicious proxy servers from transparently replacing the public certificates with their own and wiretapping the TLS connection of the unsuspecting user. This header sets HPKP in enforcement mode.

Reference...

We have seen 101 websites setting the Public-Key-Pins HTTP header and 68 unique values of this header.

  • xalqbank.az pin-sha256="brv29mkNjXj9ulIMcRDP980MZlakfmG18jl3HAD12BI="; max-age=5184000
  • cdnjs.com pin-sha256="EULHwYvGhknyznoBvyvgbidiBH3JX3eFHHlIO3YK8Ek=";pin-sha256="x9SZw6TwIqfmvrLZ/kz1o0Ossjmn728BnBKpUFqGNVM=";max-age=3456000;report-uri="https://cdnjs.report-uri.io/r/default/hpkp/enforce
  • webcookies.org pin-sha256="YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg="; pin-sha256="Vjs8r4z+80wjNcr1YKepWQboSIRi63WsWXhIMN+eWys="; pin-sha256="sRHdihwgkaib1P1gxX8HFszlD+7/gTfNvuAybgLPNis="; pin-sha256="C5+lpZ7tcVwmwQIMcRtPbsQtWLABXhQzejna0wHFr8M="; max-age=15552000; includeSubDomains; report-uri="http://reports.krvtz.net/hpkp; report-to=hpkp"
  • vcp.ovpn.to pin-sha256="oe6PZcrhoX7wqST+PANlTVXEospkClhlVf8/LG1thS4="; pin-sha256="tWPKCZ5Y8zYrtI5M4YUREMryXgTcQ2oEocmT2PAjxfM="; max-age=15552000
  • www.btpn.com pin-sha256="RvJtPNE/TrsAePIEgcS8bzO5XB3OiXg3L4mfjBdZhYE="; max-age=5184000
  • ing.ro pin-sha256="n9jiY0Yhon+a8cavnkKs32pHzpQkueLkxPb1V4jy/GI="; max-age=5184000; includeSubDomains
  • www.firma-cerny.cz pin-sha256="OGW8QPsHzNfmt3lUouSb1qZDxqAy3so0dpB2/167XLk="; pin-sha256="YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg="; pin-sha256="47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="; includeSubDomains; max-age=15552000
  • um.edu.my pin-sha256="klO23nT2ehFDXCfx3eHTDRESMz3asj1muO+4aIdjiuY="; pin-sha256="633lt352PKRXbOwf4xSEa1M517scpD3l5f79xMD9r9Q="; max-age=2592000; includeSubDomains
  • cmharyanacell.nic.in pin-sha256="d6qzRu9zOECb90Uez27xWltNsj0e1Md7GkYYkVoZWmM="; pin-sha256="E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g="; max-age=604800; report-uri="https://example.net/pkp-report"
  • rexdl.com pin-sha256=""; pin-sha256=""; max-age=31536000
  • www.der-mond.org pin-sha256="base64+primary=="; pin-sha256="base64+backup=="; max-age=5184000; includeSubDomains
  • www.ibhonold.com pin-sha256="base64+primary=="; pin-sha256="base64+backup=="; max-age=5184000; includeSubDomains
  • cdn.firma-cerny.cz pin-sha256="OGW8QPsHzNfmt3lUouSb1qZDxqAy3so0dpB2/167XLk="; pin-sha256="YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg="; pin-sha256="47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="; includeSubDomains; max-age=15552000
  • espci.fr pin-sha256="86KB9Slpbb53RONIoGjs5/257KEo1kvrbnoLxKxEFPk="; pin-sha256="G2yynb2dhIY76y4MNvVJHgPOmqY2Jl2lOdzSjf/cWMs="; pin-sha256="R57IIVyvNVfihr4s2oGxMrGrc1JCV3MgaNTSgWPFQVg="; pin-sha256="V3Ib7OSrBSFcfNuhj8E4TxL98BM3eYbDHTxfSgneYSQ="; pin-sha256="qY4ObBo/os7U5E34CuyhtRMIJnxNiPieNvVWTgx/YyI="; pin-sha256="r2zRk6OtdJZeJC+KLFWep3UDds/TyCuF5oOz5rPJ730="; pin-sha256="sW294j1ImTj+DIChcDXrr+eXfEgCHDV46wdFKKznWrY="; max-age=86400
  • w53.net.espci.fr pin-sha256="86KB9Slpbb53RONIoGjs5/257KEo1kvrbnoLxKxEFPk="; pin-sha256="G2yynb2dhIY76y4MNvVJHgPOmqY2Jl2lOdzSjf/cWMs="; pin-sha256="R57IIVyvNVfihr4s2oGxMrGrc1JCV3MgaNTSgWPFQVg="; pin-sha256="V3Ib7OSrBSFcfNuhj8E4TxL98BM3eYbDHTxfSgneYSQ="; pin-sha256="qY4ObBo/os7U5E34CuyhtRMIJnxNiPieNvVWTgx/YyI="; pin-sha256="r2zRk6OtdJZeJC+KLFWep3UDds/TyCuF5oOz5rPJ730="; pin-sha256="sW294j1ImTj+DIChcDXrr+eXfEgCHDV46wdFKKznWrY="; max-age=86400
  • stats.espci.fr pin-sha256="OjSlFGq2ch5RtvBcMesHlDORXRmrM8req8bpAGAckD0="; pin-sha256="mD1E7Txb8mIbSbGR2FHf6liFfjn+WVAi9R07w7TRS84="; max-age=86400
  • stg-collections.nationalgallery.sg pin-sha256='X3pGTSOuJeEVw989IJ/cEtXUEmy52zs1TZQrU06KUKg='; pin-sha256='MHJYVThihUrJcxW6wcqyOISTXIsInsdj3xK8QrZbHec='; pin-sha256='isi41AizREkLvvft0IRW4u3XMFR2Yg7bvrF7padyCJg='; includeSubdomains; max-age=2592000
  • www.tanzschule-yvette.de pin-sha256="REQ6REU6OUY6QTQ6MEU6NkE6NUY6QTk6NzE6NDc6REY6QkQ6QjI6NUM6RDg6Q0Y6NTQ6RDI6RkE6RjE6MDI6MjY6ODM6RDc6OTg6NUE6MTU6MkM6ODk6Qzg6NDM6Rjg="; pin-sha256="grgimFH2ZXxNHIqXB3c8U2sSAfz0IeYUvjd5gRdFDhg="; max-age=5184000; includeSubDomains
  • yoyoost.ga pin-sha256="Vjs8r4z+80wjNcr1YKepWQboSIRi63WsWXhIMN+eWys="; pin-sha256="sRHdihwgkaib1P1gxX8HFszlD+7/gTfNvuAybgLPNis="; pin-sha256="YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg="; pin-sha256="C5+lpZ7tcVwmwQIMcRtPbsQtWLABXhQzejna0wHFr8M="; max-age=31536000; includeSubDomains
  • www.immuniweb.com pin-sha256="te6PjatIE3TrFLfHolT3G9i1QjriB5A8WmMe/LAFfUo="; pin-sha256="3Ywbo/+pFIjP8evCapM9dErrM8AbxOdn/aKvy8GdSzM="; max-age=15768000; report-uri="https://www.immuniweb.com/hpkp/"
  • www.hbor.hr pin-sha256="78HHKrVfDJLH2x9eOK41fqwKgDH11NXOa3St0N6BPl8="; pin-sha256="klO23nT2ehFDXCfx3eHTDRESMz3asj1muO+4aIdjiuY="; max-age=2592000; includeSubDomains
  • www.microvb.com pin-sha256="D47dKq3TDp9f7XRMhCuRvGqVdLYVbTu1uhttsU7HpVA="; pin-sha256="yS7t2Zr2U6geMTg/P2709IzZsEkOYwGlLurbJrE2YAY="; max-age=5184000
  • fluke667.host pin-sha256="W58VU4UqbLvxCT+fQvcvrvnzBxflAVdZfUh9XlyXdF4="; pin-sha256="r+zpFN7FC0Prp7i+E7qZrUpw5sy9sYSyR3m1eAxZoyE="; max-age=5184000; includeSubDomains
  • bebef.de pin-sha256="wgouzLrJOWveynuUGVvPKfOIOKK7iG8KkJR3q06nhrQ="; pin-sha256="7jLm5+WBuD2tDfTL62YhDZX1T1rn8g60CmgGTfTK9F4="; max-age=31536000;
  • tube.alfbot.xyz pin-sha256="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; pin-sha256="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; max-age=5184000; includeSubDomains