The paper of the designers of ed25519 specifies the design of the curve: the modulo is 2 to the 255th power - 19 (note that it's how the curve got its name), in

The paper of the designers of ed25519 specifies the design of the curve: the modulo is 2 to the 255th power - 19 (note that it's how the curve got its name), in the table you quote it's equvalent to (roughly) 3000 RSA bits: https://ed25519.cr.yp.to/ed25519-20110926.pdf https://ed25519.cr.yp.to/ed25519-20110926.pdf