Generating High-Entropy Passphrases

Your Root CA passphrase protects everything. This guide shows you how to generate one using only physical objects — no software, no trust required.

Understanding Entropy

Entropy measures the randomness in your passphrase. It's expressed in bits. Each bit doubles the number of possible passphrases an attacker must try.

Method 1: Diceware (Dice)

Diceware uses standard six-sided dice to select words from a public word list. Each word adds approximately 12.9 bits of entropy.

What You Need

• 5 six-sided dice (standard board game dice)
• The EFF Diceware word list (printable PDF)
• Pen and paper (to be destroyed after memorization)

Step-by-Step

Step 1: Roll 5 dice

Roll all 5 dice at once. Read them left-to-right to form a 5-digit number.

Roll: ⚂ ⚄ ⚁ ⚅ ⚃
Result: 3 5 2 6 4 → 35264

Step 2: Look up the word

Find the number 35264 in the EFF word list. Let's say it maps to the word "kidney".

Step 3: Repeat for each word

Repeat the process to generate as many words as you need:

Step 4: Assemble the passphrase

Join the words with spaces (or dashes, or no separator — the entropy is the same).

kidney-atlas-flame-oyster-gutter-flint-widow

Method 2: Coin Flip (Binary)

A coin is a 1-bit random number generator. Heads = 1, Tails = 0. You can build any random value from coin flips.

What You Need

• 1 coin (any fair coin)
• The EFF short word list (~1,296 words, indexed 1–1296)
• Pen and paper

Approach A: Binary-to-Word

Each word on the EFF short list has an index from 1 to 1296. You need 11 coin flips to generate a number in range (2¹¹ = 2048, reject if > 1296).

Step 1: Flip 11 coins

Flips:  H T T H H T H T H H T
Binary: 1 0 0 1 1 0 1 0 1 1 0
Decimal: 1 + 0 + 0 + 128 + 64 + 0 + 16 + 0 + 4 + 2 + 0 = 622

Read the binary number from left to right. The leftmost flip is the most significant bit (1024), and the rightmost is the least (1).

Position values: 1024 512 256 128 64 32 16 8 4 2 1
Flips:              1   0   0   1  1  0  1 0 1 1 0
                 1024 + 0 + 0 + 128 + 64 + 0 + 16 + 0 + 4 + 2 + 0 = 1238

Step 2: Reject if out of range

If the number is greater than 1296, discard it and flip again. This happens about 37% of the time with 11 flips, so you'll occasionally need to re-do a set.

Step 3: Look up and repeat

Look up word #1238 in the short list. Repeat for 6–10 words.

Approach B: Direct Binary Passphrase

For the technically inclined, you can skip the word list entirely and generate a raw binary passphrase encoded as hexadecimal.

Generate 128 bits

Flip a coin 128 times. Record each flip as 1 (heads) or 0 (tails). Group into nibbles (4 bits) and convert to hex:

Flips:  1001 1010 1100 0011 ...
Hex:     9     A    C    3  ...
Result: 9AC3... (32 hex characters = 128 bits)

Best Practices

Do

• ✅ Use physical randomness (dice, coins) for Root CA passphrases
• ✅ Write the passphrase on paper until memorized, then destroy the paper
• ✅ Store a backup in a fireproof safe or split with Shamir's Secret Sharing
• ✅ Use at least 7 Diceware words (90 bits) for production Root CAs
• ✅ Practice typing your passphrase daily until it becomes muscle memory

Don't

• ❌ Never use a passphrase generated by software for air-gapped Root CAs — you can't verify the entropy source
• ❌ Never use song lyrics, book quotes, or personal information
• ❌ Never store your passphrase digitally alongside the key file
• ❌ Never reuse a passphrase across different CAs or systems
• ❌ Never use "common substitutions" (e.g., p@ssw0rd) — attackers model these

Entropy Comparison

Where Trinity Uses Your Passphrase

Trinity prompts for a passphrase during two critical operations:

Both keys are encrypted with the same passphrase during trinity init. You only need to remember one passphrase, but it protects both your Root CA signing key and your Kyber transport key.

Next Steps

• Getting Started — Use your new passphrase to initialize a Root CA
• Authority Reference — Full CLI command reference
• Blind Drops Protocol — How post-quantum encryption protects your CSRs