Zig Requires Chilkat v11.0.0+

RSA Sign Binary Data and Verify (Recover the Original Data)

See more RSA Examples

Demonstrates how to RSA sign binary data and then verify/recover the original data.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

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.

    // Load an RSA private key for signing.
    const priv_key = try chilkat.PrivateKey.init();
    defer priv_key.deinit();
    priv_key.loadEncryptedPemFile("qa_data/pem/rsa_passwd.pem", "passwd") catch {
        std.debug.print("{s}\n", .{try priv_key.getLastErrorText(alloc)});
        return;
    };

    const rsa = try chilkat.Rsa.init();
    defer rsa.deinit();
    rsa.usePrivateKey(priv_key) catch {};

    // We have some binary data (in hex) to sign
    const original_data = "0102030405060708090A";
    const bd = try chilkat.BinData.init();
    defer bd.deinit();
    bd.appendEncoded(original_data, "hex") catch {};

    // If successful, the contents of bd are replaced with the RSA signature.
    rsa.signRawBd(bd) catch {
        std.debug.print("{s}\n", .{try rsa.getLastErrorText(alloc)});
        return;
    };

    // Show the RSA signature in base64
    std.debug.print("{s}\n", .{try bd.getEncoded(alloc, "base64")});

    // ------------------------------------------
    // Get the public key from the private key
    const pub_key = try chilkat.PublicKey.init();
    defer pub_key.deinit();
    priv_key.toPublicKey(pub_key) catch {};

    // Verify the signature and extract the original data.
    const rsa2 = try chilkat.Rsa.init();
    defer rsa2.deinit();
    rsa2.usePublicKey(pub_key) catch {};

    const b_verified = if (rsa2.verifyRawBd(bd)) true else |_| false;
    std.debug.print("signature verified: {}\n", .{b_verified});

    // Show the original data:
    std.debug.print("original data: {s}\n", .{try bd.getEncoded(alloc, "hex")});
}