Zig Requires Chilkat v11.0.0+

Generate RSA Key and Sign a String

See more RSA Examples

Demonstrates how to generate a new RSA public/private key pair and use it to generate a signature for a string. The (binary) digital signature is returned as a hexidecimalized string. 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 rsa = try chilkat.Rsa.init();
    defer rsa.deinit();

    // Generate a 2048-bit RSA key.
    const priv_key = try chilkat.PrivateKey.init();
    defer priv_key.deinit();
    try rsa.genKey(2048, priv_key);

    rsa.usePrivateKey(priv_key) catch {};

    // Return the signature in hex.
    rsa.setEncodingMode("hex");

    const str_data = "This is the string to be signed.";

    // Sign the SHA256 hash of the string.
    const hex_sig = try rsa.signStringENC(alloc, str_data, "sha256");

    std.debug.print("{s}\n", .{hex_sig});

    // Now verify the signature:
    const pub_key = try chilkat.PublicKey.init();
    defer pub_key.deinit();
    priv_key.toPublicKey(pub_key) catch {};
    rsa.usePublicKey(pub_key) catch {};

    if (rsa.verifyStringENC(str_data, "sha256", hex_sig)) {
        std.debug.print("Signature verified!\n", .{});
    } else |_| {
        std.debug.print("{s}\n", .{try rsa.getLastErrorText(alloc)});
    }

    // Try it with an invalid signature:
    if (rsa.verifyStringENC(str_data, "sha256", "not a valid sig")) {
        std.debug.print("Signature verified!\n", .{});
    } else |_| {
        std.debug.print("Signature validation failed!\n", .{});
    }

    // Try it with invalid data:
    if (rsa.verifyStringENC("Not the original data", "sha256", hex_sig)) {
        std.debug.print("Signature verified!\n", .{});
    } else |_| {
        std.debug.print("Signature validation failed!\n", .{});
    }
}