Function spki_sha256 

pub fn spki_sha256(
    certificate: &CertificateDer<'_>,
) -> Result<[u8; 32], Box<dyn Error + Sync + Send>>

Available on crate features crypto and std only.

Compute the SHA-256 digest of the certificate’s SubjectPublicKeyInfo.

This is the industry-standard TLS pin input, usually exchanged in the sha256/<base64 digest> format.