Key escrow is the term. See this paper from 1997: https://www.cdt.org/wp-content/uploads/pdfs/paper-key-escrow.pdf https://www.cdt.org/wp-content/uploads/pdfs/

Key escrow is the term. See this paper from 1997: https://www.cdt.org/wp-content/uploads/pdfs/paper-key-escrow.pdf https://www.cdt.org/wp-content/uploads/pdfs/paper-key-escrow... And this from 2015: https://academic.oup.com/cybersecurity/article/1/1/69/2367066 https://academic.oup.com/cybersecurity/article/1/1/69/236706... See also https://cdt.org/insights/the-nsas-split-key-encryption-proposal-is-not-serious/ https://cdt.org/insights/the-nsas-split-key-encryption-propo...