Dropbear (software)
Alternative SSH server and client
title: "Dropbear (software)" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["cryptographic-software", "free-network-related-software", "free-security-software", "secure-shell", "software-using-the-mit-license", "free-software-programmed-in-c"] description: "Alternative SSH server and client" topic_path: "general/cryptographic-software" source: "https://en.wikipedia.org/wiki/Dropbear_(software)" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Alternative SSH server and client ::
::data[format=table title="Infobox software"]
| Field | Value |
|---|---|
| name | Dropbear |
| developer | Matt Johnston |
| released | |
| latest release version | |
| latest release date | |
| latest preview version | |
| latest preview date | |
| programming language | C |
| operating system | Unix-like |
| genre | Remote access |
| license | MIT license |
| website | |
| :: |
| name = Dropbear | developer = Matt Johnston | released = | latest release version = | latest release date = | latest preview version = | latest preview date = | programming language = C | operating system = Unix-like | genre = Remote access | license = MIT license | website =
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.
Technology
Dropbear implements version 2 of the Secure Shell (SSH) protocol.{{cite web | url=https://manpages.ubuntu.com/manpages/focal/en/man8/dropbear.8.html | title=dropbear(8) | publisher=Ubuntu | access-date=2020-05-23}}
The cryptographic algorithms are implemented using third-party cryptographic libraries like LibTomCrypt included internally in the Dropbear distribution. It derives some parts from OpenSSH to handle BSD-style pseudo terminals.{{cite web | url=https://matt.ucc.asn.au/dropbear/dropbear.html | title=Dropbear SSH | author=Matt Johnston | quote=PTY handling code is taken from OpenSSH | access-date=2020-05-23}}
Features
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.{{Cite web | url=https://secure.ucc.asn.au/hg/dropbear/rev/fe6bca95afa7 | title=Makefile.in contains updated files required | author=Matt Johnston | date=2004-06-01 | access-date=2020-05-23
Dropbear supports elliptic curve cryptography for key exchange, as of version 2013.61test and beyond.{{cite web | url=https://matt.ucc.asn.au/dropbear/CHANGES | title=CHANGES | date=14 November 2013 | quote=ECC (elliptic curve) support. Supports ECDSA hostkeys (requires new keys to be generated) and ECDH for setting up encryption keys[...] | access-date=2020-05-23}}
References
References
- (2019-09-04). "VA Technical Reference Model v 24.4. Dropbear Secure Shell (SSH) Server".
- Liu, Dale. (2011-04-18). "Next Generation SSH2 Implementation: Securing Data in Motion". Syngress.
- Aufranc, Jean-Luc. (October 6, 2011). "Dropbear: Lightweight SSH Server".
::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::