Use the Camel FTP option to specify the cipher to use with SFTP.
Camel FTP option:
ciphers
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Camel 2.8.2, 2.9: SFTP only Set a comma separated list of ciphers that will be used in order of preference. Possible cipher names are defined by JCraft JSCH. Some examples include: aes128-ctr,aes128-cbc,3des-ctr,3des-cbc,blowfish-cbc,aes192-cbc,aes256-cbc. If not specified the default list from JSCH will be used.
The allowed ciphers are listed here: http://www.jcraft.com/jsch/
You will need to install additional cipher/cryptography: https://www.qvera.com/kb/index.php/1351/stronger-encryption-cryptography-extension-unlimited-strength?show=1351#q1351
Note: Additional Camel FTP options can be found here: http://camel.apache.org/ftp2.html