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Add arcfour Cipher to Mojave 10.14 [Resolved]

Im trying to use the arcfour cipher with SSH. Yes, I am aware of the risks, but I have my own reasons for wanting to use it. When I list available ciphers, it's not there. Is it possible to add it in?

Available ciphers:

$ ssh -Q cipher
3des-cbc
aes128-cbc
aes192-cbc
aes256-cbc
rijndael-cbc@lysator.liu.se
aes128-ctr
aes192-ctr
aes256-ctr
aes128-gcm@openssh.com
aes256-gcm@openssh.com
chacha20-poly1305@openssh.com

Attempt to use arcfour:

$ ssh -c arcfour file2
Unknown cipher type 'arcfour'

Question Credit: Dave
Question Reference
Asked March 25, 2019
Posted Under: Apple
58 views
1 Answers

Support for Arcfour was disabled by default in OpenSSH 7.2 (Feb 2016), and was subsequently removed completely in OpenSSH 7.6 (Oct 2017). macOS 10.14 ships with OpenSSH 7.9, which is several major versions beyond this removal.

In theory, you could reverse some of the changes applied in OpenSSH 7.6 to readd support for Arcfour. However, doing so will require significant C programming experience.

In practice, I would advise you to reconsider what you are doing.


credit: duskwuff
Answered March 25, 2019
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