bash_tls

A minimal TLS 1.2 implementation in a pure Bash script

bash_tls implements TLS well enough to make a simple HTTPS request to most web servers.

Usage

./bash_tls.sh [https://website.com/path/to/file]
If a URL is not given, defaults to https://www.google.com/robots.txt.

Features

• Supports a single cipher suite: TLS_RSA_WITH_AES_128_GCM_SHA256
  • RSA key exchange
  • HMAC-SHA256 as pseudorandom function
  • AES in GCM mode for encryption
• Supports Server Name Indication

Missing

• Only supports RSA certificates
• Does not validate certificate chain

Dependencies

bash_tls depends only on the following software:

• bash 4.3+ compiled with --enable-net-redirections
• GNU bc (for doing RSA calculations)
• sha256sum (from Linux coreutils) or shasum (on Mac)

Performance

Don't ask.