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Example for both AES-128 and ChaCha20 to Encrypt Binary Data

See more Encryption Examples

Demonstrates the use of the new EncryptBd and DecryptBd methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt binary bytes.

Note: This example requires Chilkat v9.5.0.67 or greater.

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.

    // Load a small JPG file to be encrypted/decrypted.
    const jpg_bytes = try chilkat.BinData.init();
    defer jpg_bytes.deinit();
    jpg_bytes.loadFile("qa_data/jpg/starfish.jpg") catch {
        std.debug.print("Failed to load JPG file.\n", .{});
        return;
    };

    // Show the unencrypted JPG bytes in Base64 format.
    // (The "base64_mime" encoding was added in Chilkat v9.5.0.67.
    // The "base64" encoding emits a single line of base64, whereas
    // "base64_mime" will emit multi-line base64 as it would appear
    // in MIME.)
    std.debug.print("{s}\n", .{try jpg_bytes.getEncoded(alloc, "base64_mime")});

    // Sample base64_mime JPG data:

    //     /9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    //     AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    //     AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    //     MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    //     ...

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

    // Specify the encryption to be used.
    // First we'll do AES-128 CBC
    crypt.setCryptAlgorithm("aes");
    crypt.setCipherMode("cbc");
    crypt.setKeyLength(128);

    const iv_hex = "000102030405060708090A0B0C0D0E0F";
    crypt.setEncodedIV(iv_hex, "hex");

    const key_hex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
    crypt.setEncodedKey(key_hex, "hex");

    // Do the in-place 128-bit AES CBC encryption.
    // The contents of jpgBytes are replaced with the encrypted bytes.
    crypt.encryptBd(jpg_bytes) catch {
        std.debug.print("{s}\n", .{try crypt.getLastErrorText(alloc)});
        return;
    };

    // Examine the JPG bytes again.  The bytes should be different because they are encrypted:
    std.debug.print("{s}\n", .{try jpg_bytes.getEncoded(alloc, "base64_mime")});

    // Sample base64_mime encrypted JPG data:

    //     sbz0babt1WCkQf5xKMdg/baZAcUBO5GVUUDF2BjVqmd+HrqKN+t6hAcqakL/bdo0q9hYmow0Tp1e
    //     AQ9V9DOiifQUZqWVkR+kL/c45bq8JGFDvgNl0djPt+yYhV789IB/fPH0upx+/ad++WNOlv1IxGMr
    //     Y1x1oERU/IsiEzafUJdI4kZ6FQo2IPGMF/Rm1h79I7hP1yYUFxvJyz+PzaySAUH1nLsNHyDVY5VY
    //     O90aH3steRSYbz8C8UF9wQ3qqEIXQNnnixvoNDnmHyY39VoVBI5F6rnPwYDfAk2t8tmuryFqvwAu
    //     ...

    // Decrypt to restore back to the original:
    crypt.decryptBd(jpg_bytes) catch {
        std.debug.print("{s}\n", .{try crypt.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{try jpg_bytes.getEncoded(alloc, "base64_mime")});

    //     /9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    //     AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    //     AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    //     MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    //     ...

    // ----------------------------------------------------------------------------------
    // To do chacha20 encryption, just change the settings:

    crypt.setCryptAlgorithm("chacha20");
    crypt.setKeyLength(256);
    // The initial count is the initial block counter for the chacha20 algorithm.
    // It can be any integer, but must be set to the same when decrypting.
    crypt.setInitialCount(22);

    try crypt.encryptBd(jpg_bytes);
    // jpgBytes now contains chacha20 encrypted bytes.

    try crypt.decryptBd(jpg_bytes);
    // jpgBytes is now restored back to the original unencrypted by bytes.

    // Save the bytes to a file..
    try jpg_bytes.writeFile("qa_output/starfish.jpg");

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