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Generating Certificates for Bumper

The scripts/create-cert.sh helper will generate all necessary certificates into the certs/ directory for both Bumper and mitmproxy.

📂 Script Location & Overview

  • Path: scripts/create-cert.sh
  • Purpose:
    • Create a root CA (ca.key + ca.crt)
    • Issue a server certificate (bumper.key + bumper.crt)
    • Produce a combined PEM (ca.pem) for mitmproxy by merging CA and server certs

If you already possess your own certs, simply place them in certs/:

  • ca.crt, bumper.key, bumper.crt for Bumper
  • ca.pem for mitmproxy

🚀 Execute the Script

$./scripts/create-cert.sh

On success, the certs/ directory contains:

  • ca.key  – Root CA private key
  • ca.crt  – Root CA certificate
  • bumper.key – Server private key
  • bumper.crt – Server certificate
  • ca.pem  – Combined CA+server cert (for mitmproxy)

The script skips existing files to protect your keys.

⚙️ Using Certificates

Bumper Application

Configure Bumper to load certificates (defaults shown):

BUMPER_CERTS=certs
BUMPER_CA=ca.crt
BUMPER_CERT=bumper.crt
BUMPER_KEY=bumper.key

Or point directly to full paths:

BUMPER_CA_PATH=certs/ca.crt
BUMPER_CERT_PATH=certs/bumper.crt
BUMPER_KEY_PATH=certs/bumper.key

mitmproxy

Mount ca.pem into your mitmproxy container or CLI:

$docker run --rm -it \
  -v $PWD/certs/ca.pem:/home/mitm/ca.pem:ro \
  mitmproxy/mitmproxy mitmweb \
    --certs '*=/home/mitm/ca.pem'

🐍 Python Configuration (Advanced)

Bumper’s Python Config class reads these env vars if set:

Variable Default Description
BUMPER_CERTS ./certs Certificates directory
BUMPER_CA ca.crt CA cert filename
BUMPER_CERT bumper.crt Server cert filename
BUMPER_KEY bumper.key Server key filename

Note: ca.pem is only needed by mitmproxy; Bumper uses individual CRT/KEY files.