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Verify and Unwrap S/MIME, and get Information about CMS Signature

See more MIME Examples

Demonstrates calling the Verify method to verify and unwrap S/MIME. The MIME is restored to the original structure that it would have originally had prior to signing. The Verify method works with both detached signatures, as well as opaque/attached signatures.

Calls LastJsonData to get information about the signature(s) that were verified.

Chilkat Zig Downloads

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

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

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

    const mime = try chilkat.Mime.init();
    defer mime.deinit();

    // Load the signed MIME from a file...
    mime.loadMimeFile("qa_data/mime/detached_sig.eml") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // Verify the S/MIME and restore the MIME
    // to the structure/content it had prior to signing.
    mime.verify() catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // Examine the details of what was verified.
    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    mime.getLastJsonData(json);

    json.setEmitCompact(false);
    std.debug.print("{s}\n", .{try json.emit(alloc)});

    // The code to parse the following JSON (i.e. extract desired information) is shown below..

    // {
    //   "pkcs7": {
    //     "verify": {
    //       "certs": [
    //         {
    //           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
    //           "serial": "0702A21A85B84B659E180A6EE6F5A365"
    //         },
    //         {
    //           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
    //           "serial": "008B5B75568454850B00CFAF3848CEB1A4"
    //         },
    //         {
    //           "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
    //           "serial": "619C55C32FF6BD1A7B7E0330D21C8F3C"
    //         }
    //       ],
    //       "digestAlgorithms": [
    //         "sha1"
    //       ],
    //       "signerInfo": [
    //         {
    //           "cert": {
    //             "serialNumber": "619C55C32FF6BD1A7B7E0330D21C8F3C",
    //             "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
    //             "digestAlgOid": "1.3.14.3.2.26",
    //             "digestAlgName": "SHA1"
    //           },
    //           "contentType": "1.2.840.113549.1.7.1",
    //           "signingTime": "160428055000Z",
    //           "messageDigest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY=",
    //           "signingAlgOid": "1.2.840.113549.1.1.1",
    //           "signingAlgName": "RSA-PKCSV-1_5",
    //           "authAttr": {
    //             "1.2.840.113549.1.9.3": {
    //               "name": "contentType",
    //               "oid": "1.2.840.113549.1.7.1"
    //             },
    //             "1.2.840.113549.1.9.5": {
    //               "name": "signingTime",
    //               "utctime": "160428055000Z"
    //             },
    //             "1.2.840.113549.1.9.4": {
    //               "name": "messageDigest",
    //               "digest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY="
    //             },
    //             "1.2.840.113549.1.9.15": {
    //               "der": "MFAwCwYJYIZIAWUDBAECMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKA=="
    //             },
    //             "1.3.6.1.4.1.311.16.4": {
    //               "der": "MIG7MIG...7fgMw0hyPPA=="
    //             }
    //           }
    //         }
    //       ]
    //     }
    //   }
    // }

    // Use this online tool to generate parsing code from sample JSON:
    // Generate Parsing Code from JSON

    const signing_time = try chilkat.DtObj.init();
    defer signing_time.deinit();
    const auth_attr_signing_time_utctime = try chilkat.DtObj.init();
    defer auth_attr_signing_time_utctime.deinit();
    var issuer_cn: [:0]const u8 = "";
    var serial: [:0]const u8 = "";
    var str_val: [:0]const u8 = "";
    var cert_serial_number: [:0]const u8 = "";
    var cert_issuer_cn: [:0]const u8 = "";
    var cert_digest_alg_oid: [:0]const u8 = "";
    var cert_digest_alg_name: [:0]const u8 = "";
    var content_type: [:0]const u8 = "";
    var message_digest: [:0]const u8 = "";
    var signing_alg_oid: [:0]const u8 = "";
    var signing_alg_name: [:0]const u8 = "";
    var auth_attr_content_type_name: [:0]const u8 = "";
    var auth_attr_content_type_oid: [:0]const u8 = "";
    var auth_attr_signing_time_name: [:0]const u8 = "";
    var auth_attr_message_digest_name: [:0]const u8 = "";
    var auth_attr_message_digest_digest: [:0]const u8 = "";
    var auth_attr1_2_840_113549_1_9_15_der: [:0]const u8 = "";
    var auth_attr1_3_6_1_4_1_311_16_4_der: [:0]const u8 = "";

    var i: i32 = 0;
    var count_i: i32 = json.sizeOfArray("pkcs7.verify.certs");
    while (i < count_i) {
        json.setI(i);
        issuer_cn = try json.stringOf(alloc, "pkcs7.verify.certs[i].issuerCN");
        serial = try json.stringOf(alloc, "pkcs7.verify.certs[i].serial");
        i = i + 1;
    }

    i = 0;
    count_i = json.sizeOfArray("pkcs7.verify.digestAlgorithms");
    while (i < count_i) {
        json.setI(i);
        str_val = try json.stringOf(alloc, "pkcs7.verify.digestAlgorithms[i]");
        i = i + 1;
    }

    i = 0;
    count_i = json.sizeOfArray("pkcs7.verify.signerInfo");
    while (i < count_i) {
        json.setI(i);
        cert_serial_number = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].cert.serialNumber");
        cert_issuer_cn = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].cert.issuerCN");
        cert_digest_alg_oid = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].cert.digestAlgOid");
        cert_digest_alg_name = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].cert.digestAlgName");
        content_type = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].contentType");
        json.dtOf("pkcs7.verify.signerInfo[i].signingTime", false, signing_time) catch {};
        message_digest = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].messageDigest");
        signing_alg_oid = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].signingAlgOid");
        signing_alg_name = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].signingAlgName");
        auth_attr_content_type_name = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".name");
        auth_attr_content_type_oid = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".oid");
        auth_attr_signing_time_name = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".name");
        json.dtOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".utctime", false, auth_attr_signing_time_utctime) catch {};
        auth_attr_message_digest_name = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".name");
        auth_attr_message_digest_digest = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".digest");
        auth_attr1_2_840_113549_1_9_15_der = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.15\".der");
        auth_attr1_3_6_1_4_1_311_16_4_der = try json.stringOf(alloc, "pkcs7.verify.signerInfo[i].authAttr.\"1.3.6.1.4.1.311.16.4\".der");
        i = i + 1;
    }
}