Zig

Check for an S/MIME Signing Time

Demonstrates the Chilkat Mime.HasSignatureSigningTime method, which returns whether the signer at a zero-based index included a CMS signingTime signed attribute. The only argument is the signer index; use NumSignerCerts for the count.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: A signing time records when the signer claims to have signed, which matters for auditing and for validating a certificate that has since expired. It is an optional signed attribute, so not every signature has one — this predicate lets you check before calling GetSignatureSigningTimeStr, avoiding an error for signers that omitted it. Being a signed attribute, it is covered by the signature and cannot be altered undetected.

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Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    const mime = try chilkat.Mime.init();
    defer mime.deinit();
    mime.loadMimeFile("qa_data/signed.eml") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // After verifying, check whether each signer included a CMS signingTime signed attribute.  The
    // only argument is the zero-based signer index.
    mime.verify() catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    const n = mime.getNumSignerCerts();
    var i: i32 = 0;
    i = 0;
    while (i < n) : (i += 1) {
        if (mime.hasSignatureSigningTime(i)) {
            std.debug.print("Signer {d} included a signing time.\n", .{i});
        } else {
            std.debug.print("Signer {d} did not include a signing time.\n", .{i});
        }
    }
}