The weakness to all encryption, to all security, is time. What if the time that it took to crack an encryption was drastically cut down. Quantum computers may be more than a decade away, but they not just may, but will, exponentially cut down the time it takes to crack an encryption. This week there is going to be a computer security convention at Schloss Dagstuhl–Leibniz Center for Informatics in Wadern, Germany concentrating on quantum-resistant replacements the currently used encryption. This convention is only one of the many convention that have recently been held or are about to be held. Examples of other conventions include the workshop NIST, the US National Institute of Standards and Technology, in April, and the IQC team up with the European Telecommunications Standards Institute in October. The NSA also revealed that it has plans to upgrade to quantum resistant protocols. The Dutch Intelligence services also pointed out the threat of people/corporations/governments intercepting and storing information now to decrypt when the quantum computers are complete.
One of the most used encryptions as of now is called RSA encryption. This is one of the encryptions that will be rendered obsolete when quantum computers are used. “PQCRYPTO, a European consortium of quantum-cryptography researchers in academia and industry, released a preliminary report on 7 September recommending cryptographic techniques that are resistant to quantum computers.” PQCRYPTO gave recommendations for four different types of encryption, symmetric encryption, symmetric authentication, public-key encryption, and public-key signatures. A symmetric encryption is “the oldest and best-known technique. A secret key, which can be a number, a word, or just a string of random letters, is applied to the text of a message to change the content in a particular way. This might be as simple as shifting each letter by a number of places in the alphabet. As long as both sender and recipient know the secret key, they can encrypt and decrypt all messages that use this key.”1 For symmetric encryption, PQCRYPTO recommends AES-256, and Salsa20 with a 256-bit key.3 Symmetric authentication is when “the user shares a unique, secret key (usually embedded in a hard token) with an authentication server. The user is authenticated by sending to the authentication server his/her username together with a randomly generated message (the challenge) encrypted by the secret key. If the server can match the received encrypted message (the response) using its share secret key, the user is authenticated.”2 For Symmetric authentication, PQCRYPTO recommends GCM using a 96- bit nonce and a 128-bit authenticator, and Poly1305.3 Public-key encryption, also known as asymmetric-key encryption, is when “there are two related keys–a key pair. A public key is made freely available to anyone who might want to send you a message. A second, private key is kept secret, so that only you know it. Any message (text, binary files, or documents) that are encrypted by using the public key can only be decrypted by applying the same algorithm, but by using the matching private key. Any message that is encrypted by using the private key can only be decrypted by using the matching public key.”1 For public-key encryption, PQCRYPTO recommends McEliece with binary Goppa codes using length n = 6960, dimension k = 5413 and adding t = 119 errors. For public-key signatures, PQCRYPTO recommends XMSS, and SPHINCS-256.3
By Eric Weitzman