Zig

CoSign PKCS7/CMS Signed Data

See more Digital Signatures Examples

Demonstrates how to add a 2nd signature to a CMS SignedData. This is to add an additional signature, SignerInfo and certificate(s) to an existing CMS signed data.

In this example, we cosign an existing pdf.p7s

Note: The CoSign method is added in Chilkat v9.5.0.89.

Zig

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

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

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    const crypt = try chilkat.Crypt2.init();
    defer crypt.deinit();
    const cert = try chilkat.Cert.init();
    defer cert.deinit();

    // If loading from a smart card, set the smartcard PIN.
    cert.setSmartCardPin("0000");

    // Load a certificate in some way, such as from a smart card.
    // Chilkat provides other methods to load from a .pfx, .pem, or from the Windows certificate stores..
    cert.loadFromSmartcard("") catch {
        std.debug.print("{s}\n", .{try cert.getLastErrorText(alloc)});
        return;
    };

    crypt.setSigningCert(cert) catch {
        std.debug.print("{s}\n", .{try crypt.getLastErrorText(alloc)});
        return;
    };

    // Load the file to be co-signed.
    // NOTE:  This is to cosign a PDF file contained within a CMS (PKCS7) message.
    // (In other words, the PDF is contained within the CMS SignedData, rather than the other way around
    // where a CMS signature is contained within a PDF.  Use Chilkat's PDF class to sign a PDF, which is
    // to embed a CMS signature within the PDF.)
    const bd = try chilkat.BinData.init();
    defer bd.deinit();
    bd.loadFile("qa_data/p7s/cosign/sample.pdf.p7s") catch {
        std.debug.print("Failed to load pdf.p7s input file.\n", .{});
        return;
    };

    // bd2 will contain the co-signed result.
    const bd2 = try chilkat.BinData.init();
    defer bd2.deinit();
    crypt.coSign(bd, cert, bd2) catch {
        std.debug.print("{s}\n", .{try crypt.getLastErrorText(alloc)});
        return;
    };

    bd.writeFile("qa_output/cosigned.pdf.p7s") catch {
        std.debug.print("Failed to save pdf.p7s output file.\n", .{});
        return;
    };

    std.debug.print("Success!\n", .{});
}