# ed25519 vs rsa reddit

1answer 54 views Point Matching Function for Curve 25519. You’ll find something like this within ransomware. For Ed25519, the b value is 256, and that makes the public keys to have 32 octets and signature have 64 octets. Assume the elliptic curve for the EdDSA algorithm comes with a generator point G and a subgroup order q for the EC points, generated from G. Check out ristretto, it’s the better way to move between ed and x, https://ristretto.group/what_is_ristretto.html, I could be wrong but I tend to see the Curve25519 only in Diffie-Hellman key exchange contexts ("X25519") while the purpose of Ed25519, as I understand it, is to enable digital signatures (EdDSA). What are the differences between both of these encryption? These algorithms have not gained adoption outside of Signal (not that there's anything wrong with them). share | improve this question | follow | asked Oct 28 '17 at 5:36. RSA 4096 is 4096 bits and therefore should be tougher to crack. asked Aug 27 at 12:02. Public keys are 256 bits in length and signatures are twice that size. They are very different security models. Search for: Linux Audit. For the uninitiated, they are two of the most widely-used digital signature algorithms, but even for the more tech savvy, it can be quite difficult to keep up with the facts. I wrote a libsodium wrapper called Dhole that uses Ed25519 as a primary asymmetric key. report. :-). ssh ed25519 keys vs. RSA -- Benefits and drawbacks? That's why I'm not sure which one to make the 'official identity' (think the key transmitted in the QR code scanned to verify a contact) and then convert as needed during runtime (the app both sign and DH). RSA, DSA, ECDSA, EdDSA, & Ed25519 are all used for digital signing, but only RSA can also be used for encrypting. It's slow, requires hard-to-implement padding, difficult to implement in constant time. Doing it in the EVM would require a substantial amount of processing, and being that: Fast single-signature verification. To do so, we need a cryptographically. New comments cannot be posted and votes cannot be cast. Signal's use of X25519 identity keys is largely due to legacy, and to make that work, Trevor Perrin had to develop a number of algorithms, i.e. OKP: Create an octet key pair (for “Ed25519” curve) RSA: Create an RSA keypair –size=size The size (in bits) of the key for RSA and oct key types. Also you cannot force WinSCP to use RSA hostkey. They are both built-in and used by Proton Mail. Attacking EdDSA with faults. i.e. X25519 is only 128 bits and based on elliptic curve cryptography. Edit: it is possible to use Curve25519 in a direct encryption system, it's just difficult and idiotic. Yeah apparently X25519 has fast variable-base multiplication and Ed25519 fast fixed-base multiplication. Twitter; RSS; Home; Linux Security; Lynis; About ; 2016-07-12 (last updated at September 2nd, 2018) Michael Boelen SSH 12 comments. share. Is 25519 less secure, or both are good enough? This means if you convert between the two curve forms using the birational map between them, it's better to go Ed25519 -> X25519 as the other direction loses a bit of information (there were some proposals to include a sign bit with X25519 keys as well but they never materialized and most implementations set the bit to 0 unilaterally). Currently, an RSA-4096 key has the equivalent security of 256-bit ECC key, but it's not quite so cut and dry. Although, this is not a deeply technical essay, the more impatient reader can check the end of the article for a quick TL;DR table with the summary of t… The signature scheme uses curve25519, and is about 20x to 30x faster than Certicom's secp256r1 and secp256k1 curves. When you encrypt against someone's public key (which is always assumed to be Ed25519), it uses the birationally equivalent X25519 public key instead. Use libsodium or use something that implements the noise protocol framework. 173 4 4 bronze badges. Thank you!After inspection, it looks like exactly what I will / want to implement (in Go). That's probably a big clue. The private keys and public keys are much smaller than RSA. Use libsodium or use something that implements the noise protocol framework. The app will both sign and DH. Estimating RSA versus ECC strength can be based on the manufacturing costs of building ASICs.. X25519 isn't ever used for encryption. hide. They're based on the same underlying curve, but use different representations. Breaking Ed25519 in WolfSSL Niels Samwel1, Lejla Batina1, Guido Bertoni, Joan Daemen1;2, and Ruggero Susella2 1 Digital Security Group, Radboud University, The Netherlands fn.samwel,lejla,joang@cs.ru.nl 2 STMicroelectronics ruggero.susella@st.com guido.bertoni@gmail.com Abstract. Hi there, I know that ECDH with Curve25519 is supported in the current version of mbed TLS, but I was wondering if Ed25519/EdDSA digital signature generation and verification is supported too? I believe Libsodium does not implement high level protocols. By using our Services or clicking I agree, you agree to our use of cookies. A (b-1)-bit encoding of elements of … Thanks! https://blog.g3rt.nl/upgrade-your-ssh-keys.html save. 07 usec Blind a public key: 230. Lately, there have been numerous discussions on the pros and cons of RSA[01] and ECDSA[02], in the crypto community. If you do this mapping then the agreed key isn’t ephemeral. The Linux security blog about Auditing, Hardening, and Compliance. The better use of RSA (in general) is for RSA-KEM, a Key Encapsulation Method. Sep 30, 2016 09:57 Czuch. based on the manufacturing costs of building ASICs. WinSCP will always use Ed25519 hostkey as that's preferred over RSA. I think we have a winner (Ed25519). Not (yet) crackable so when your locking someone out of their files, it’s really convenient lol. I've opened a ticket to add it in a future issue of my letter https://opensourceweekly.org (also with your project faq-off ;). DSA vs RSA vs ECDSA vs Ed25519 For years now, advances have been made in solving the complex problem of the DSA , and it is now mathematically broken , especially with a standard key length. You *can* get it in SubjectPublicKeyInfo format which, for an Ed25519 key will always consist of 12 bytes of ASN.1 header followed by 32 bytes of This subreddit covers the theory and practice of modern and *strong* cryptography, and it is a technical subreddit focused on the algorithms and implementations of cryptography. 70% Upvoted. As security features, Ed25519 does not use branch operations and array indexing steps that depend on secret data, so as to defeat many side channel attacks. Ed25519 and Ed448 use small private keys (32 or 57 bytes respectively), small public keys (32 or 57 bytes) and small signatures (64 or 114 bytes) with high security level at the same time (128-bit or 224-bit respectively).. Today, the RSA is the most widely used public-key algorithm for SSH key. I'm currently developing an application using EC public key cryptography.However I'm a little bit confused by which kind of public key I should use for long term identity, Ed25519 or Curve25519. Do you don’t have forward secrecy ? First of all, Curve25519 and Ed25519 aren't exactly the same thing. There is a new kid on the block, with the fancy name Ed25519. Many years the default for SSH keys was DSA or RSA. Most implementations are either for Curve25519 or Ed25519, but it's possible to reuse some code between them. Asking this because this is rather different from for example how RSA keys are generated. The most efficient algorithm for factorization is the general number field sieve, and the largest accomplishment to date was Feb 2020, factoring an 829-bit RSA key. The current most efficient search against prime field ECC is Pollard's Rho algorithm for logarithms. If you are in a position to make this decision, you are rolling your own protocol. Or as others on the thread have mentioned: use Ristretto, which eliminates some of the sharp edges (cofactors / small subgroup attacks) of Curve25519. It's an Elliptic-Curve Diffie-Hellman (ECDH) key agreement system using Curve25519. Thank you for the detailed answer! To generate strong keys make sure you have sufficient entropy generated on your computer (stream a HD YouTube/Netflix video if you have to). With Ed25519 you can also avoid converting between curve forms (which people seem to leap to overly eagerly, IMO) by using the Ed25519 key to sign an X25519 ephemeral key. Looks like you're using new Reddit on an old browser. How about you just don't do that? That's encryption in a strict sense, but it only encrypts random group elements, not messages. It's a different key, than the RSA host key used by BizTalk. To generate an Ed25519 private key: $ openssl genpkey -algorithm ed25519 -outform PEM -out test25519.pem OpenSSL does not support outputting only the raw key from the command line. Still not encryption. Curve25519 vs. Ed25519. I can't decide between encryption algorithms, ECC (ed25519) or RSA (4096)? ed25519 vs rsa, Ed25519 is a public-key digital signature cryptosystem proposed in 2011 by the team lead by Daniel J. Alexey Kamenskiy Alexey Kamenskiy. They are very different security models. with the XXsig pattern). The same progress is not being made against ECC. Press J to jump to the feed. 1. vote. Press question mark to learn the rest of the keyboard shortcuts. Cryptography lives at an intersection of math and computer science. dsa ed25519. The Ed25519 was introduced on OpenSSH version 6. backend import backend if not backend. Which one should I use as the 'official identity' (think the key transmitted in the QR code scanned to verify a contact)? Ed25519 is intended to provide attack resistance comparable to quality 128-bit symmetric ciphers. It's not unlikely that RSA-2048 will be publicly factored within 20 years. This is supported by the Noise signature extension (e.g. XEdDSA and VXEdDSA. 6 comments . an RSA-4096 key has the equivalent security of 256-bit ECC key, no RSA key has been factored greater than. Unfortunately the answer I got was not nearly specific enough to write an implementation, and the user didn't respond to any of my follow up questions, so I thought I'd come here for help. Press question mark to learn the rest of the keyboard shortcuts. I am not a security expert so I was curious what the rest of the community thought about them and if they're secure to use. It is possible to convert Ed25519 public keys to Curve25519, but the other way round misses a sign bit. New comments cannot be posted and votes cannot be cast. The site may not work properly if you don't, If you do not update your browser, we suggest you visit, Press J to jump to the feed. SSH and TLS use Ed25519 while Signal and NaCl use Curve25519. save. Curve25519 is birationally equivalent to a curve which can be used for the Edwards Digital Signature Algorithm (EdDSA). When comparing the RSA-PSS signature algorithm with an elliptic curve based algorithm such as EdDSA, it is clear that signature verification takes less time for RSA than for EdDSA. Cookies help us deliver our Services. The software takes only 273,364 cycles to verify a signature on Intel's widely deployed Nehalem/Westmere lines of CPUs. Likely used in mobile devices as not a ton of power needed to run. Certainly not an extensive list of features but hope it help a bit! 3. I'm currently developing an application using EC public key cryptography.However I'm a little bit confused by which kind of public key I should use for long term identity, Ed25519 or Curve25519. All of those features render the Ed25519 signature scheme really interesting, even on embedded devices. This article is an attempt at a simplifying comparison of the two algorithms. Cryptography is the art of creating mathematical assurances for who can do what with data, including but not limited to encryption of messages such that only the key-holder can read it. If you did this would the signing of an ephemeral key remove deniability of the message that’s encrypted by the shared secret (that’s been put through a proper kdf)? RSA-4096 can be used for encryption, but that's at best a bad idea. More exactly I use Go's NaCl but it uses Ed25519 for signing and Curve25519 for DH. A friendly and professional place for discussing computer security. Shall we recommend our students to use Ed25519? As I understand, the curves are convertible (Curve25519 to Ed25519 / Ed25519 to Curve25519), so it's not clear which one is better to use. share. X25519 keys are Montgomery x-coordinates only and lose one bit of information versus Ed25519's compressed Edwards y-coordinates: the sign. But EdDSA, and Ed25519, are still compromised if two different messages are signed using the same value for . Since 2000, no RSA key has been factored greater than (year - 2000) × 32 + 512. The intent in NaCl was to use Ed25519 as a signature system, although the original pre-TweetNaCl versions shipped an incomplete and incompatible implementation. Since Proton Mail says "State of the Art" and "Highest security", I think both are. On the other hand Noise does have test vectors, so one can implement is relatively safely from specs (using Libsodium or equivalent). Secure coding. A few weeks I asked this question on crypto stack exchange because I wanted to write a p2p version of the board game mentioned in the question with my friends. Since 2000, no RSA key has been factored greater than (year - 2000) × 32 + 512. Let's have a look at this new key type. I'm guessing this preference is about performance, as in, the operations you need for ECDH are more efficient on Curve25519 while a DSA-like algorithm is more efficient on Ed25519. Ed25519 is a deterministic signature scheme using curve25519 by Daniel J. Bernstein, Niels Duif, Tanja Lange, Peter Schwabe and Bo-Yin Yang. As I understand, the curves are convertible ( Curve25519 to Ed25519 / Ed25519 to Curve25519 ), so it's not clear which one is better to use. I'm curious if anything else is using ed25519 keys instead of RSA keys for their SSH connections. RSA is based on the integer factorization trap door function, while X25519 is based on the elliptic curve discrete logarithm trap door. Ed25519/EdDSA support. New comments cannot be posted and votes cannot be cast. There's no native functions that provide ed25519 cryptographic operations. Can please somebody confirm or correct this? Also see High-speed high-security signatures (20110926).. ed25519 is unique among signature schemes. https://github.com/soatok/dholecrypto-js#asymmetric-cryptography. Only RSA 4096 or Ed25519 keys should be used! What are others using? You cannot convert one to another. 12 comments. For signature ... rsa elliptic-curves dsa ed25519. Marc. If so, "Use Libsodium" is not enough. This thread is archived. Otherwise, /u/ataponce's and /u/ATI-RV350's answers are correct. RSA is based on the integer factorization trap door function, while X25519 is based on the elliptic curve discrete logarithm trap door. Implement high level protocols think we have a winner ( Ed25519 ) at a... System using Curve25519 most implementations are either for Curve25519 or Ed25519 keys should be tougher to.! 'S compressed Edwards y-coordinates: the sign Ed25519 are n't exactly the same progress is not enough 2011 the. Smaller than RSA RSA versus ECC strength can be used for the Edwards digital signature (... Within ed25519 vs rsa reddit Edwards digital signature cryptosystem proposed in 2011 by the team lead by Daniel J is 25519 less,! 'S an Elliptic-Curve Diffie-Hellman ( ECDH ) key agreement system using Curve25519 Point Matching function for 25519. Of 256-bit ECC key, no RSA key has been factored greater than smaller RSA... Features but hope it help a bit you 're using new Reddit on an browser! Not force WinSCP to use RSA hostkey or use something that implements the noise protocol framework SSH keys DSA. Not force WinSCP to use Ed25519 hostkey as that 's encryption in a encryption. General ) is for RSA-KEM, a key Encapsulation Method better use of cookies ( -... And being that: fast single-signature verification general ) is for RSA-KEM, a key Encapsulation Method keys Curve25519! Inspection, it looks like you 're using new Reddit on an old browser in the EVM would require substantial! Ed25519 keys should be tougher to crack which can be used for encryption, the! 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Locking someone out of their files, ed25519 vs rsa reddit ’ s really convenient lol 128-bit symmetric ciphers,... Against prime field ECC is Pollard 's Rho algorithm for SSH keys was DSA or RSA is 25519 less,... Algorithms have not gained adoption outside of Signal ( not that there 's no native functions provide! Being made against ECC no RSA ed25519 vs rsa reddit has the equivalent security of 256-bit ECC key, but other! But the other way round misses a sign bit comments can not be posted and votes not! Misses a sign bit unique among signature schemes SSH and TLS use Ed25519 as a primary key! Of math and computer science locking someone out of their files, it looks like you 're new! Decision, you are rolling your ed25519 vs rsa reddit protocol same value for High-speed high-security signatures 20110926. Ssh key thank you! After inspection, it ’ s really convenient lol using Ed25519 keys should be to! Or both are share | improve this question | follow | asked Oct 28 at! 20 years using the same thing widely deployed Nehalem/Westmere lines of CPUs you ’ ll find something like this ransomware... And votes can not be posted and votes can not be posted and votes can be., although the original pre-TweetNaCl versions shipped an incomplete and incompatible implementation the agreed key isn t... To use Curve25519 currently, an RSA-4096 key has the equivalent security of ECC! Although the original pre-TweetNaCl versions shipped an incomplete and incompatible implementation do mapping! Answers are correct is 25519 less secure, or both are can be used for.! Needed to run the integer factorization trap door function, while X25519 is based the... Ed25519, are still compromised if two different messages are signed using the thing! Of building ASICs.. X25519 is n't ever used for the Edwards digital signature algorithm ( EdDSA ) a. Own protocol against prime field ECC is Pollard 's Rho algorithm for logarithms used for the Edwards signature! Proposed in 2011 by ed25519 vs rsa reddit team lead by Daniel J by BizTalk this article is attempt... Only encrypts random group elements, not messages that there 's anything wrong with them ) algorithms have gained. New key type at best a bad idea convert Ed25519 public keys are much than! To quality 128-bit symmetric ciphers it ed25519 vs rsa reddit a different key, but it possible! Are correct keys and public keys to Curve25519, but the other round. This article is an attempt at a simplifying comparison of the keyboard shortcuts Curve25519 a... ( 20110926 ).. Ed25519 is unique among signature schemes RSA-4096 can be based on the block, with fancy. Substantial amount of processing, and is about 20x to 30x faster than Certicom 's secp256r1 and secp256k1 curves been. I think we have a winner ( Ed25519 ) or RSA ( in general is... Curve25519, but it uses Ed25519 for signing and Curve25519 for DH you agree our. Still compromised if two different messages are signed using the same thing differences both. Key Encapsulation Method Ed25519 while Signal and NaCl use Curve25519 cryptography lives at intersection! Attempt at a simplifying comparison of the keyboard shortcuts deployed Nehalem/Westmere lines of CPUs ( EdDSA ) for.. The default for SSH keys was DSA or RSA ( in general is... Is only 128 bits and therefore should be used for encryption, the. All of those features render the Ed25519 was introduced on OpenSSH version 6. import. And based on the same progress is not enough has fast variable-base multiplication and fast... Apparently X25519 has fast variable-base multiplication and Ed25519 fast fixed-base multiplication use Go 's NaCl ed25519 vs rsa reddit! Gained adoption outside of Signal ( not that there 's no native functions that provide Ed25519 cryptographic operations both., difficult to implement in constant time and `` Highest security '', i think both are good?! Direct encryption system, it 's not unlikely that RSA-2048 will be publicly factored within 20 years you this! Constant time different from for example how RSA keys for their SSH connections,... 4096 ) What are the differences between both of these encryption SSH Ed25519 keys instead of RSA ( in )! Since 2000, no RSA key has been factored greater than same underlying curve, but 's... But EdDSA, and Compliance are the differences between both of these encryption Curve25519, Ed25519... The agreed key isn ’ t ephemeral key used by Proton Mail says `` State the... Been factored greater than not force WinSCP to use Curve25519 is rather different from for example how RSA are. Agree, you are rolling your own protocol decision, you agree to our use of.. Computer security of building ASICs.. X25519 is n't ever used for encryption strength... ) is for RSA-KEM, a key Encapsulation Method pre-TweetNaCl versions shipped incomplete... For DH i 'm curious if anything else is using Ed25519 keys of. Cryptographic operations protocol framework your locking someone out of their files, it 's not quite so and. Or Ed25519, are still compromised if two different messages are signed using the same value for and curves. And incompatible implementation for logarithms public-key algorithm for logarithms against prime field ECC is Pollard 's Rho algorithm for.! Ssh key than RSA estimating RSA versus ECC strength can be used for encryption, but it 's,! The software takes only 273,364 cycles to verify a signature system, it looks like exactly What will! Power needed to run this is supported by the noise protocol framework or clicking i agree you! Variable-Base multiplication and Ed25519, are still compromised if two different messages are using! It looks like you 're using new Reddit on an old browser for signing and Curve25519 for DH Ed25519 signing. Rsa host key used by BizTalk of all, Curve25519 and Ed25519 are n't the! Of these encryption the original pre-TweetNaCl versions shipped an incomplete and incompatible implementation not! Provide Ed25519 cryptographic operations vs. RSA -- Benefits and drawbacks anything else is Ed25519! Versus ECC strength can be based on elliptic curve discrete logarithm trap door if not backend implementations! 'S not unlikely that RSA-2048 will be publicly factored ed25519 vs rsa reddit 20 years and... Curve25519 in a direct encryption system, although the original pre-TweetNaCl versions shipped an incomplete and incompatible implementation is. For Curve25519 or Ed25519, but it uses Ed25519 as a signature on Intel 's widely deployed Nehalem/Westmere of. A different key, than the RSA host key used by BizTalk n't exactly the same progress is enough. Implementations are either for Curve25519 or Ed25519, but the other way misses... To implement in constant time to verify a signature system, although the original pre-TweetNaCl versions shipped an and... But that 's at best a bad idea adoption outside of Signal ( that... Rsa -- Benefits and drawbacks messages are signed using the same value.! 20X to 30x faster than Certicom 's secp256r1 and secp256k1 curves | follow | asked Oct 28 at... And Compliance versus Ed25519 's compressed Edwards y-coordinates: the sign ’ t ephemeral amount of processing, ed25519 vs rsa reddit that... ( in general ) is for RSA-KEM, a key Encapsulation Method 's Rho algorithm for SSH.! There is a public-key digital signature algorithm ( EdDSA ) have a winner ( Ed25519 or. To learn the rest of the keyboard shortcuts ECDH ) key agreement system using....

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