Source: /cirosantilli/one-time-pad

= One-time pad
{wiki}

The only perfect cryptosystem!

The problem is that you need a shared <key (cryptography)> as large as the message.

Systems like <advanced Encryption Standard> allow us to encrypt things larger than the key, but the tradeoff is that they could be possibly broken, as don't have any <provably secure symmetric-key algorithms> as of 2020.