Struct Fingerprint 

pub struct Fingerprint {
    pub func: HashFunc,
    pub digest: Vec<u8>,
}

One a=fingerprint value (RFC 8122 §5).

Fields

func: HashFunc

Which hash it was taken with.

digest: Vec<u8>

The digest itself, as octets rather than as text — a fingerprint is compared to a hash of a certificate, and keeping it as the printed form would mean re-parsing to do that.

Implementations

impl Fingerprint

pub fn of(certificate: &[u8], func: HashFunc) -> Self

The fingerprint of a DER-encoded certificate, taken with func.

pub fn parse(value: &str) -> Option<Self>

Read an a=fingerprint value: <hash-func> SP <2UHEX *(":" 2UHEX)>.

Returns None for a hash sipx may not act on, a malformed digest, or a digest whose length does not match the function named. The last check matters: a truncated digest that compared equal against the first bytes of a certificate hash would be a fingerprint check that verifies almost nothing.

pub fn to_value(&self) -> String

Render as an a=fingerprint value.

Uppercase hex: §5’s UHEX rule is DIGIT / %x41-46, which is uppercase only. Lowercase is what most implementations accept anyway, and is still not what the grammar says.

pub fn matches(&self, certificate: &[u8]) -> bool

Whether a certificate is the one this fingerprint names (RFC 8122 §6.2).

Compared in constant time. The value is public, so this is not about protecting the digest — it is about not giving an attacker who can offer certificates a byte-at-a-time oracle for how far a forged one matched.

Trait Implementations

impl Clone for Fingerprint

fn clone(&self) -> Fingerprint

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Fingerprint

fn fmt(&self, f: &mut Formatter<'_>) -> Result

The digest is not a secret, but printing 64 hex pairs in a log line is noise. The function and the length are what a reader is looking for.

impl PartialEq for Fingerprint

fn eq(&self, other: &Fingerprint) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Fingerprint

impl StructuralPartialEq for Fingerprint