Struct Signature 

pub struct Signature {

    pub v: u32,
    pub a: Algorithm,
    pub d: String,
    pub s: String,
    pub b: Vec<u8>,
    pub bh: Vec<u8>,
    pub h: Vec<String>,
    pub z: Vec<String>,
    pub i: String,
    pub l: u64,
    pub x: u64,
    pub t: u64,
    pub r: bool,
    pub atps: Option<String>,
    pub atpsh: Option<HashAlgorithm>,
    pub ch: Canonicalization,
    pub cb: Canonicalization,
}

A DKIM1 signature: the tag list of a DKIM-Signature header (RFC 6376, Section 3.5).

Obtained by parsing a header value with Signature::parse, from a verified message through DkimOutput::signature, or as the result of signing with DkimSigner. It is written back as a header through HeaderWriter or Signature::write. Each field is named after its tag.

Fields

v: u32

v=: signature version; 1, or 0 when the tag is absent from a parsed header.

a: Algorithm

a=: signing algorithm (RFC 6376, RFC 8301, RFC 8463).

d: String

d=: signing domain identifier (SDID), the domain claiming responsibility for the message.

s: String

s=: selector; the key record is looked up at <s>._domainkey.<d>.

b: Vec<u8>

b=: signature data, base64 decoded.

bh: Vec<u8>

bh=: hash of the canonicalized body, base64 decoded.

h: Vec<String>

h=: names of the signed header fields, in signing order.

z: Vec<String>

z=: copied header fields, as name:value strings with quoted printable decoded (diagnostic only).

i: String

i=: agent or user identifier (AUID); empty when absent.

l: u64

l=: body length in octets covered by the body hash; 0 means the tag is absent and the whole body is signed.

x: u64

x=: signature expiration, in seconds since the UNIX epoch; 0 means no expiration.

t: u64

t=: signing time, in seconds since the UNIX epoch; 0 when absent.

r: bool

r=y: the signer requests failure reports (RFC 6651, Section 3.1).

atps: Option<String>

atps=: the domain authorizing this third-party signature (RFC 6541, Section 4.1).

atpsh: Option<HashAlgorithm>

atpsh=: hash algorithm applied to d= when building the ATPS query name; None means atpsh=none, where d= is used verbatim (RFC 6541, Section 4.1).

ch: Canonicalization

Header canonicalization, the first half of the c= tag.

cb: Canonicalization

Body canonicalization, the second half of the c= tag.

Implementations

impl Signature

pub fn write(&self, writer: &mut impl Writer, as_header: bool)

Writes the signature as a DKIM-Signature header.

With as_header set, writes DKIM-Signature: <tags>;\r\n, folded with \r\n\t, ready to prepend to a message; this is what HeaderWriter::write_header does. With as_header unset, writes the form hashed during signing: no trailing CRLF and, under relaxed header canonicalization, a lowercase dkim-signature: name folded with single spaces. Tags with default values (i=, t=, x=, l=, r=, atps=) are omitted.

impl Signature

pub fn parse(header: &[u8]) -> Result<Self>

Parses the value of a DKIM-Signature header (RFC 6376, Section 3.5).

header is the raw header value, after the colon. Unknown tags are ignored. When c= is absent, simple/simple is assumed. An atpsh= value other than sha1, sha256 or none clears the ATPS domain so that no ATPS check can succeed.

Errors

• DkimError::UnsupportedVersion when v= is present and not 1.
• DkimError::UnsupportedAlgorithm for an unknown a= value.
• DkimError::UnsupportedCanonicalization for an unknown c= value.
• Error::Base64 when b= or bh= is not valid base64.
• Error::Parse when i= is not valid quoted printable.
• Error::MissingParameters when any of d=, s=, b=, bh= or h= is missing or empty.

impl Signature

pub fn identity(&self) -> &str

Returns the agent or user identifier (the i= tag), or an empty string when the tag is absent.

Trait Implementations

impl Clone for Signature

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Signature

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

Formats the value using the given formatter.

impl Default for Signature

fn default() -> Self

Returns the “default value” for a type.

impl Display for Signature

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

Formats the value using the given formatter.

impl Eq for Signature

impl HeaderWriter for Signature

fn write_header(&self, writer: &mut impl Writer)

Writes the complete header field, including the field name and the trailing CRLF, to writer.

fn to_header(&self) -> String

Returns the complete header field as a string, including the field name and the trailing CRLF. Invalid UTF-8 is replaced with U+FFFD.

impl PartialEq for Signature

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Signature

impl VerifySignature for Signature

fn signature(&self) -> &[u8]

Returns the decoded signature data (b= tag).

fn algorithm(&self) -> Algorithm

Returns the signing algorithm (a= tag).

fn selector(&self) -> &str

Returns the selector (s= tag).

fn domain(&self) -> &str

Returns the signing domain (d= tag).

fn domain_key(&self) -> String

Returns the fully qualified name of the key record, <selector>._domainkey.<domain>., with a trailing dot.