Zig Requires Chilkat v11.0.0+

Validate JWS Using RSASSA-PKCS1-v1_5 SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) that uses RSASSA-PKCS1-v1_5 SHA-256. Zig

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

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

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

    // This example takes a JSON signature in compact serialization format,
    // and uses an RSA public key to validate and recover the protected header and payload.

    // We only need a public key for signature validation.  This is the RSA public key
    // that is used:

    //      {"kty":"RSA",
    //       "n":"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx
    //            HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs
    //            D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH
    //            SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV
    //            MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8
    //            NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ",
    //       "e":"AQAB"
    //      }

    const sb_pub_key = try chilkat.StringBuilder.init();
    defer sb_pub_key.deinit();
    sb_pub_key.append("{\"kty\":\"RSA\",") catch {};
    sb_pub_key.append("\"n\":\"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx") catch {};
    sb_pub_key.append("HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs") catch {};
    sb_pub_key.append("D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH") catch {};
    sb_pub_key.append("SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV") catch {};
    sb_pub_key.append("MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8") catch {};
    sb_pub_key.append("NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ\",") catch {};
    sb_pub_key.append("\"e\":\"AQAB\"") catch {};
    sb_pub_key.append("}") catch {};

    const pub_key = try chilkat.PublicKey.init();
    defer pub_key.deinit();
    pub_key.loadFromString(try sb_pub_key.getAsString(alloc)) catch {
        std.debug.print("{s}\n", .{try pub_key.getLastErrorText(alloc)});
        return;
    };

    const jws = try chilkat.Jws.init();
    defer jws.deinit();

    // Set the RSA public key:
    const signature_index = 0;
    jws.setPublicKey(signature_index, pub_key) catch {};

    // Load the JWS.
    const sb_jws = try chilkat.StringBuilder.init();
    defer sb_jws.deinit();
    sb_jws.append("eyJhbGciOiJSUzI1NiJ9") catch {};
    sb_jws.append(".") catch {};
    sb_jws.append("eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt") catch {};
    sb_jws.append("cGxlLmNvbS9pc19yb290Ijp0cnVlfQ") catch {};
    sb_jws.append(".") catch {};
    sb_jws.append("cC4hiUPoj9Eetdgtv3hF80EGrhuB__dzERat0XF9g2VtQgr9PJbu3XOiZj5RZmh7") catch {};
    sb_jws.append("AAuHIm4Bh-0Qc_lF5YKt_O8W2Fp5jujGbds9uJdbF9CUAr7t1dnZcAcQjbKBYNX4") catch {};
    sb_jws.append("BAynRFdiuB--f_nZLgrnbyTyWzO75vRK5h6xBArLIARNPvkSjtQBMHlb1L07Qe7K") catch {};
    sb_jws.append("0GarZRmB_eSN9383LcOLn6_dO--xi12jzDwusC-eOkHWEsqtFZESc6BfI7noOPqv") catch {};
    sb_jws.append("hJ1phCnvWh6IeYI2w9QOYEUipUTI8np6LbgGY9Fs98rqVt5AXLIhWkWywlVmtVrB") catch {};
    sb_jws.append("p0igcN_IoypGlUPQGe77Rw") catch {};

    jws.loadJwsSb(sb_jws) catch {
        std.debug.print("{s}\n", .{try jws.getLastErrorText(alloc)});
        return;
    };

    // Validate the 1st (and only) signature at index 0..
    const v = jws.validate(signature_index);
    if (v < 0) {
        // Perhaps Chilkat was not unlocked or the trial expired..
        std.debug.print("Method call failed for some other reason.\n", .{});
        std.debug.print("{s}\n", .{try jws.getLastErrorText(alloc)});
        return;
    }

    if (v == 0) {
        std.debug.print("Invalid signature.  The RSA key was incorrect, the JWS was invalid, or both.\n", .{});
        return;
    }

    // If we get here, the signature was validated..
    std.debug.print("Signature validated.\n", .{});
    std.debug.print("--\n", .{});

    // Recover the original content:
    std.debug.print("Recovered content:\n", .{});
    std.debug.print("{s}\n", .{try jws.getPayload(alloc, "utf-8")});
    std.debug.print("--\n", .{});

    // Examine the protected header:

    const jose_header = try chilkat.JsonObject.init();
    defer jose_header.deinit();
    jws.getProtectedH(signature_index, jose_header) catch {
        std.debug.print("{s}\n", .{try jws.getLastErrorText(alloc)});
        return;
    };

    jose_header.setEmitCompact(false);

    std.debug.print("Protected (JOSE) header:\n", .{});
    std.debug.print("{s}\n", .{try jose_header.emit(alloc)});

    // Output:

    //     Signature validated.
    //     --
    //     Recovered content:
    //     {"iss":"joe",
    //      "exp":1300819380,
    //      "http://example.com/is_root":true}
    //     --
    //     Protected (JOSE) header:
    //     {
    //       "alg": "RS256"
    //     }
}