ykman piv info returning certificate serial number in decimal

[Yubi-David]

• YubiKey Manager (ykman) version: 5.0.1
• How was it installed?: MSI
• Operating system and version: Win 11
• YubiKey model and version: YK5 NFC, USB-A, FW 5.4.3
• Bug description summary: The command ykman piv info returns the certificates loaded on the device, but the certificate serial number is displayed in decimal. This is contrary to the Windows tools (certutil and certificate manager GUI), which displays the certificate serial number in hex.

Steps to reproduce

1. Generate or load a certificate onto a YubiKey PIV function.
2. Run ykman with the command ykman piv info. Note the serial number returned for the certificate.
3. Run on windows the command certutil -scinfo. Note the serial number returned for the same certificate.

Expected result

The serial number for the certificates to be identical.

Actual results and logs

ykman piv info returned the serial number in decimal, while certutil -scinfo returned the serial in hexidecimal.

Other info

N/A