Download File with Specific SSL Cipher Suite on Ubuntu

This article demonstrates how to download a file on Ubuntu while enforcing a specific SSL cipher suite using the command line. By utilizing the curl utility, you can specify encryption algorithms to ensure secure connections or maintain compatibility with specific server configurations during the transfer process.

To begin, ensure that the curl package is installed on your Ubuntu system. You can install it by opening your terminal and running the command sudo apt update && sudo apt install curl. Once installed, you can proceed to configure the SSL cipher suite for your download.

The primary method for specifying a cipher suite is using the --ciphers flag followed by the desired algorithm name. This forces curl to negotiate the connection using only the listed ciphers. The general syntax for the command is:

curl --ciphers 'CIPHER_NAME' https://example.com/file -O

Replace CIPHER_NAME with the specific SSL cipher suite you require, such as TLS_AES_256_GCM_SHA384 for TLS 1.3 or ECDHE-RSA-AES256-GCM-SHA384 for TLS 1.2. The -O flag saves the file using its remote name. For example, to download a file using a high-security cipher, you would execute:

curl --ciphers 'TLS_AES_256_GCM_SHA384' https://secure.example.com/data.zip -O

If you are unsure which ciphers are available on your system, you can verify supported protocols by checking the curl manual or testing connections with verbose output using the -v flag. This ensures that the handshake completes successfully with the specified encryption standards before downloading large files.