World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0040775836
Reproduction Date:

Title: EdDSA  
Author: World Heritage Encyclopedia
Language: English
Subject: Elliptic curve cryptography, Quantum digital signature, Digital Signature Algorithm, Libgcrypt, Merkle–Hellman knapsack cryptosystem
Publisher: World Heritage Encyclopedia


In public-key cryptography, Edwards-curve Digital Signature Algorithm (EdDSA) is a digital signature scheme using a variant of Schnorr signature based on Twisted Edwards curves. It is designed for high performance while avoiding security problems that have surfaced in other digital signature schemes. It was developed by a team including Daniel J. Bernstein, Niels Duif, Tanja Lange, Peter Schwabe, and Bo-Yin Yang.[1]


Ed25519 is a specific implementation of EdDSA using the Twisted Edwards curve:

-x^2 + y^2 = 1 -\frac{121665}{121666}x^2y^2, over the prime field defined by the prime number 2255 − 19.

This curve is birationally equivalent to the Montgomery curve known as Curve25519. The equivalence is x = \sqrt{-486664}u/v and y=(u-1)/(u+1).[1][2]



The Bernstein team have optimized Ed25519 for 64-bit processors in the x86 Nehalem/Westmere family, achieving fast key generation, document signing and signature verification. Verification can be performed in batches of 64 signatures for even greater throughput. Ed25519 is targeted to provide attack resistance comparable to quality 128-bit symmetric ciphers. Public keys are 256 bits (32 bytes) in length and signatures are twice that size.

Secure coding

Security features of Ed25519 include elimination of branch operations and array indexing steps that depend on data which must be kept secret, so as to defeat many side channel attacks. Like other digital signature algorithms, EdDSA requires a secret value, or nonce, unique to each signature, however EdDSA calculates this nonce deterministically, as the hash of the secret key and the message, rather than rely on a random number generator. This reduces the risk of a random number generator attack, but does not completely eliminate it, since high quality random numbers are still needed for key generation.


Notable uses of Ed25519 include OpenSSH, GnuPG and various alternatives, and the signify tool by OpenBSD.[3]

See also


  1. ^ a b
  2. ^
  3. ^
  4. ^
  5. ^

External links

  • Ed25519 home page

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.