openwrt/package/network/services/dropbear/Config.in
Paul Spooren d0f295837a dropbear: Enable Ed25519 for normal devices
The Ed25519 key pairs are much shorter than RSA pairs and are supported
by default in OpenSSH. Looking at websites explaining how to create new
SSH keys, many suggest using Ed25519 rather than RSA, however consider
the former as not yet widely established. OpenWrt likely has a positive
influence on that development.

As enabling Ed25519 is a compile time option, it is currently not
possible to install the feature via `opkg` nor select that option in an
ImageBuilder.

Due to the size impact of **12kB** the option should only be enabled for
devices with `!SMALL_FLASH`.

This approach seems cleaner than splitting `dropbear` into two packages
like `dropbear` and `dropbear-ed25519`.

Signed-off-by: Paul Spooren <mail@aparcar.org>
2020-09-06 23:19:20 +02:00

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menu "Configuration"
depends on PACKAGE_dropbear
config DROPBEAR_CURVE25519
bool "Curve25519 support"
default y
help
This enables the following key exchange algorithm:
curve25519-sha256@libssh.org
Increases binary size by about 4 kB (MIPS).
config DROPBEAR_ECC
bool "Elliptic curve cryptography (ECC)"
default n
help
Enables basic support for elliptic curve cryptography (ECC)
in key exchange and public key authentication.
Key exchange algorithms:
ecdh-sha2-nistp256
Public key algorithms:
ecdsa-sha2-nistp256
Increases binary size by about 24 kB (MIPS).
If full ECC support is required, also select DROPBEAR_ECC_FULL.
config DROPBEAR_ECC_FULL
bool "Elliptic curve cryptography (ECC), full support"
default n
depends on DROPBEAR_ECC
help
Enables full support for elliptic curve cryptography (ECC)
in key exchange and public key authentication.
Key exchange algorithms:
ecdh-sha2-nistp256 (*)
ecdh-sha2-nistp384
ecdh-sha2-nistp521
Public key algorithms:
ecdsa-sha2-nistp256 (*)
ecdsa-sha2-nistp384
ecdsa-sha2-nistp521
(*) - basic ECC support; provided by DROPBEAR_ECC.
Increases binary size by about 4 kB (MIPS).
config DROPBEAR_ED25519
bool "Ed25519 support"
default y if !SMALL_FLASH
help
This enables the following public key algorithm:
ssh-ed25519
Increases binary size by about 12 kB (MIPS).
config DROPBEAR_CHACHA20POLY1305
bool "Chacha20-Poly1305 support"
default y
help
This enables the following authenticated encryption cipher:
chacha20-poly1305@openssh.com
Increases binary size by about 4 kB (MIPS).
config DROPBEAR_ZLIB
bool "Enable compression"
default n
help
Enables compression using shared zlib library.
Increases binary size by about 0.1 kB (MIPS) and requires additional 62 kB (MIPS)
for a shared zlib library.
config DROPBEAR_UTMP
bool "Utmp support"
default n
depends on BUSYBOX_CONFIG_FEATURE_UTMP
help
This enables dropbear utmp support, the file /var/run/utmp is used to
track who is currently logged in.
config DROPBEAR_PUTUTLINE
bool "Pututline support"
default n
depends on DROPBEAR_UTMP
help
Dropbear will use pututline() to write the utmp structure into the utmp file.
config DROPBEAR_DBCLIENT
bool "Build dropbear with dbclient"
default y
config DROPBEAR_SCP
bool "Build dropbear with scp"
default y
endmenu