Dropbear (software)

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Developer(s)Matt Johnston
Initial releaseApril 2003, 06; 18 years ago (06-04-2003)
Stable release2020.81 (October 29, 2020; 11 months ago (2020-10-29)) [±][1]
Written inC
Operating systemUnix-like
TypeRemote access
LicenseMIT license

Dropbear is a software package written by Matt Johnston that provides a Secure Shell-compatible server and client. It is designed as a replacement for standard OpenSSH for environments with low memory and processor resources, such as embedded systems. It is a core component of OpenWrt and other router distributions.

Dropbear was originally released in April 2003.


Dropbear implements version 2 of the Secure Shell (SSH) protocol.[2]

The cryptographic algorithms are implemented using third-party cryptographic libraries included internally in the Dropbear distribution. It derives some parts from OpenSSH to handle BSD-style pseudo terminals.[3]


Dropbear implements the complete SSH version 2 protocol in both the client and the server. It does not support SSH version 1 backwards-compatibility in order to save space and resources, and to avoid the inherent security vulnerabilities in SSH version 1. SCP is also implemented.[4] SFTP support relies on a binary file which can be provided by OpenSSH or similar programs. FISH works in any case and is supported by Konqueror.

Dropbear supports elliptic curve cryptography for key exchange, as of version 2013.61test and beyond.[5]

See also[edit]


  1. ^ "Dropbear ChangeLog". 2020-10-29. Retrieved 2021-05-11.
  2. ^ "dropbear(8)". Ubuntu. Retrieved 2020-05-23.
  3. ^ Matt Johnston. "Dropbear SSH". Retrieved 2020-05-23. PTY handling code is taken from OpenSSH
  4. ^ Matt Johnston (2004-06-01). "Makefile.in contains updated files required". Retrieved 2020-05-23.
  5. ^ "CHANGES". 14 November 2013. Retrieved 2020-05-23. ECC (elliptic curve) support. Supports ECDSA hostkeys (requires new keys to be generated) and ECDH for setting up encryption keys[...]

External links[edit]