Metadata

Everything a viewer surfaces about a signature — the Signature Properties panel and the document's Document Properties — is grouped into one Metadata struct on SignConfig. The most common fields have builder shortcuts; the rest are set through .metadata(Metadata { .. }).

Signature properties

/Reason, /Location, and /ContactInfo are the free-text fields Adobe shows in the signature's properties. /Name (the signer) defaults to the certificate's CN — override it only when you want a display name different from the certificate subject.

use mudrit_pdfsign::prelude::*;

let cfg = SignConfig::builder()
    .place("F", [350, 60, 560, 160])?
    .reason("Approved for disbursement")
    .location("New Delhi")
    .contact("accounts@example.com")
    .name("Finance Department")          // optional — omit to use the certificate CN
    .build();

Signing time and time zone

The signing time /M and the visible stamp's Date: label are generated from the real wall clock. The default zone is IST (+05:30); change it with .tz_offset(secs) (pass 0 for UTC) or set an exact /M string via Metadata::signing_time.

// no tz_offset → the auto /M and visible date use IST (+05:30)
let cfg = SignConfig::builder()
    .place("F", [350, 60, 560, 160])?
    .build();

let cfg = SignConfig::builder()
    .place("F", [350, 60, 560, 160])?
    .tz_offset(0)                 // UTC instead of the default IST
    .cms_signing_time(true)       // also emit the PKCS#9 signingTime CMS attribute
    .build();

let cfg = SignConfig::builder()
    .place("F", [350, 60, 560, 160])?
    .metadata(Metadata {
        signing_time: Some("D:20260717093000+05'30'".into()),  // exact /M; tz_offset ignored
        ..Metadata::default()
    })
    .build();

Document properties (/Info + XMP)

Document-level metadata is set through DocInfo on Metadata::document. Title / Author / Subject / Keywords are simple Options (None = leave untouched); Creator ("Application") and Producer ("PDF Producer") use MetaField so you choose whether to keep, replace, or append.

let cfg = SignConfig::builder()
    .place("F", [350, 60, 560, 160])?
    .metadata(Metadata {
        document: DocInfo {
            title: Some("Q3 Report".into()),
            author: Some("Acme Corp".into()),
            subject: Some("Quarterly results".into()),
            keywords: Some("finance, q3, signed".into()),
            creator: MetaField::Set("Acme Sign 2.0".into()),   // replace the Application
            ..DocInfo::default()                               // producer keeps its Append tag
        },
        ..Metadata::default()
    })
    .build();

The Mudrit / SDK tag

Because Mudrit signs (does not author) the PDF, creator and producer default to Append: the input's originals are kept and the SDK tag Mudrit <version> (Trexolab) — derived from Cargo.toml — is appended ("{orig}; {tag}"), never replaced. Customize the appended tag with .app_tag("…"):

let cfg = SignConfig::builder()
    .place("F", [350, 60, 560, 160])?
    .app_tag("Acme Sign 2.0")     // appended to /Producer and /Creator, keeping the originals
    .build();

The tag lands on both the /Info dict and the XMP packet. For per-field control (replace one, keep the other), set MetaField::Set(..) / MetaField::Keep through .metadata(…) instead.

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