 Cryptography has long been used as a means to protect data, dating back to the Caesar cipher more than two thousand years ago. Modern cryptographic techniques are essential in any IT system that needs to store (and thus protect) personal data, for example by providing secure (confidential) connections for browsing (HTTPS) and networking (VPN). Note however that by itself cryptography does not provide any protection against data breaching; only when applied correctly in a specific context does it become a ‘fence’ around personal data. In addition, cryptographic schemes that become outdated by faster computers or new attacks may pose threats to (long-term) privacy.