Wow, thanks for the detailed reply! Actually I am a master student and my teacher wants me to figure out the use of ed25519. So I went to see openssl. I thought ed25519 can sign messages so I tried the dgst command. Now I know that I was wrong. Anyway, thank you again!
Viktor Dukhovni <openssl-us...@dukhovni.org> 于2020年4月22日周三 上午1:35写道: > On Tue, Apr 21, 2020 at 05:48:19PM +0800, yang berlin wrote: > > > I want to use ed25519 in openssl. > > Why? What actual real-world purpose do you have for ed25519? > > > The problem I met is: I can use "speed ed25519" to test the speed of > > ed25519, but when I use "dgst -ed25519", it tells me that "dgst: > > Unrecognized flag Ed25519". > > That's because "ed25519" is not a digest algorithm, it is a public key > algorithm. You can use it to sign messages, but not to compute message > digests. > > > So could you please help me to learn how to use ed25519 correctly? > > That question has no answer. Whether a use of "ed25519" is correct or > incorrect depends on the security protocol in which it is to be used, > and whether that protocol is appropriate to security requirements of > the application using it. > > If you're just playing with ed25519, you can generate ed25519 keys with: > > $ openssl genpkey -algorithm ed25519 -out privkey.pem > > You can extract just the public key via: > > $ openssl pkey -in privkey.pem -pubout -out pubkey.pem > > You can generate an ed25519 self-signed public key certificate with: > > $ openssl req -key privkey.pem -new \ > -x509 -subj "/CN=$(uname -n)" -days 36500 -out pubcert.pem > > You can use the key and certificate with s_client, and s_server > via the "-key" and "-cert" arguments. > > You can also sign and/or encrypt messages with ed25519 using cms(1), > but you may not be ready to dive into cms. > > Low-level public and private key operations are possible via pkeyutl(1). > > While the dgst(1) command supports signing message digests with various > public key signature algorithms, ed25519 is not one of these: > > -sign filename > Digitally sign the digest using the private key in "filename". > Note > this option does not support Ed25519 or Ed448 private keys. Use > the > pkeyutl command instead for this. > > See the pkeyutl(1) manpage. > > Don't assume that some use of encryption implies any gain in security. > It could be mere security theatre. For actual security you need to > apply a robust protocol that matches the application's security > requirements. > > -- > Viktor. >