Private key

1. The secret part of an asymmetric key pair that is typically used to verify, digitally sign, or decrypt data.

Source: Election Terminology Glossary - Draft, National Institute of Standards and Technology (NIST), https://pages.nist.gov/ElectionGlossary/

2. The secret part of an asymmetric key pair that is typically used to digitally sign or decrypt data.

Source: Glossary of terms database, U.S. Election Assistance Commission, https://www.eac.gov/glossary/

3. The secret part of an asymmetric key pair that is uniquely associated with an entity.

Source: Explore Terms: A Glossary of Common Cybersecurity Terminology, National Initiative for Cybersecurity Careers and Studies (NICCS),

4. A cryptographic key that must be kept confidential and is used to enable the operation of an asymmetric (public key) cryptographic algorithm. Adapted from: CNSSI 4009, NIST SP 800-63 Rev 1, FIPS 201-2, FIPS 140-2, Federal Bridge Certificate Authority Certification Policy 2.25.

Source: Explore Terms: A Glossary of Common Cybersecurity Terminology, National Initiative for Cybersecurity Careers and Studies (NICCS), https://niccs.us-cert.gov/about-niccs/glossary

5. A cryptographic key that is used with an asymmetric (public key) cryptographic algorithm. For digital signatures, the private key is uniquely associated with the owner and is not made public. The private key is used to compute a digital signature that may be verified using the corresponding public key or to decrypt information which has been encrypted using the public key.

Source: The State and Local Election Cybersecurity Playbook, Defending Digital Democracy Project, Harvard Kennedy School Belfer Center for Science and International Affairs, https://www.belfercenter.org/sites/default/files/files/publication/StateLocalPlaybook%201.1.pdf