kattis-kth/aes/src/main.zig


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const std = @import("std");

pub fn main() !void {
    const stdin = std.io.getStdIn().reader().any();
    const stdout = std.io.getStdOut().writer().any();

    const key = try stdin.readBytesNoEof(16);
    const aes = std.crypto.core.aes.Aes128.initEnc(key);

    var input: [1024 * 16]u8 = undefined;
    while (true) {
        const unalignedLen = try stdin.read(&input);
        if (unalignedLen == 0) break;
        const len = std.mem.alignBackward(usize, unalignedLen, 16);
        std.debug.assert(len == unalignedLen);
        var i: usize = 0;
        while (i < len) : (i += 16) {
            aes.encrypt(input[i..][0..16], input[i..][0..16]);
        }
        try stdout.writeAll(input[0..len]);
    }
}