https://www.yubico.com/blog/yubikey-4096-you-asked-we-delivered/
YubiKey 4(096): You Asked, We Delivered | Yubico
Jan 25, 2024 - YubiKey 4 sports several improvements and new functionality. One notable addition is support for RSA keys up to 4096 bits!
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https://www.yubico.com/blog/yubikey-4-fresh-look-attestation-capabilities/
YubiKey 4 has fresh look, attestation capabilities | Yubico
Sep 15, 2020 - The YubiKey 4 gets a facelift and introduces new trust capabilities that validate device type, manufacturer, and generated key material.
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https://fidoalliance.org/showcase/yubikey-4/
YubiKey 4 | FIDO Alliance Certified Showcase FIDO Alliance
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https://www.yubico.com/blog/tag/yubikey-4/
YubiKey 4 Archives | Yubico
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