An AEAD can be constructed from pieces made and studied for other purposes (eg. block ciphers and hash functions). There is also a cryptographic primitive which

An AEAD can be constructed from pieces made and studied for other purposes (eg. block ciphers and hash functions). There is also a cryptographic primitive which can be used for AEAD almost without modification: the cryptographic sponge. But even so this particular primitive is often tailored for the security requirements of AEAD to be more performant: https://ascon.isec.tugraz.at/specification.html https://ascon.isec.tugraz.at/specification.html An AEAD can also be made de novo. Such as AEGIS[1], which performs encryption and authentication in one pass (much like the sponges, but much more performant). [1] <https://competitions.cr.yp.to/round3/aegisv11.pdf https://competitions.cr.yp.to/round3/aegisv11.pdf>