This algorithm was introduced in OpenSSH 9.0p1; also, align the curve25519-sha256* key exchanges to keep things tidy. Signed-off-by: Peter Müller --- config/ssh/ssh_config | 2 +- config/ssh/sshd_config | 5 ++--- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/config/ssh/ssh_config b/config/ssh/ssh_config index 2e2ee60c3..ee0954d5c 100644 --- a/config/ssh/ssh_config +++ b/config/ssh/ssh_config @@ -9,7 +9,7 @@ Host * UseRoaming no # Only use secure crypto algorithms - KexAlgorithms curve25519-sha256(a)libssh.org,diffie-hellman-group-exchange-sha256 + KexAlgorithms sntrup761x25519-sha512(a)openssh.com,curve25519-sha256,curve25519-sha256(a)libssh.org,diffie-hellman-group-exchange-sha256 Ciphers chacha20-poly1305(a)openssh.com,aes256-gcm(a)openssh.com,aes128-gcm(a)openssh.com,aes256-ctr,aes192-ctr,aes128-ctr MACs hmac-sha2-512-etm(a)openssh.com,hmac-sha2-256-etm(a)openssh.com,umac-128-etm(a)openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128(a)openssh.com diff --git a/config/ssh/sshd_config b/config/ssh/sshd_config index bea5cee53..456556540 100644 --- a/config/ssh/sshd_config +++ b/config/ssh/sshd_config @@ -19,9 +19,8 @@ LoginGraceTime 30s # Limit maximum instanctes to prevent DoS MaxStartups 5 -# Only allow safe crypto algorithms (may break some _very_ outdated clients) -# See also: https://stribika.github.io/2015/01/04/secure-secure-shell.html -KexAlgorithms curve25519-sha256(a)libssh.org,diffie-hellman-group-exchange-sha256 +# Only allow safe crypto algorithms +KexAlgorithms sntrup761x25519-sha512(a)openssh.com,curve25519-sha256,curve25519-sha256(a)libssh.org,diffie-hellman-group-exchange-sha256 Ciphers chacha20-poly1305(a)openssh.com,aes256-gcm(a)openssh.com,aes128-gcm(a)openssh.com,aes256-ctr,aes192-ctr,aes128-ctr MACs hmac-sha2-512-etm(a)openssh.com,hmac-sha2-256-etm(a)openssh.com,umac-128-etm(a)openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128(a)openssh.com -- 2.34.1