Word Passphrase Generator

Purpose & User Intent: This tool solves the need for predictable yet memorable credentials by composing passphrases from words. Users include security-conscious individuals, developers provisioning accounts, IT admins enforcing passphrase policies, and teams seeking scalable credential generation. When creating accounts where password length and memorability matter, a passphrase-based approach is preferred over random letter strings.
Core Logic & Features: The tool draws random words from a source word list (built-in or custom). Required features: word_count (3–6), separator (space, dash, underscore, or none), and capitalization mode. Optional features include digits and punctuation allowances, per-word capitalization patterns, and a cap on maximum total length. Outputs include the final passphrase string, its character length, and an entropy estimate in bits. Example: with N=2048-word vocabulary and 4 words, baseline entropy is 4 × log2(2048) = 44 bits; adding 2 digits adds ~6 more bits, and a small symbol set can add additional bits.
Inputs & Outputs: Inputs: word_count (integer, 3–6, required), separator (string, default space; allowed values ' ', '-', '_', ''), capitalization (enum: none, first, title), digits_enabled (boolean), digits_count (integer when enabled), word_source (enum: built-in, custom). Outputs: passphrase (string), length (integer), entropy_bits (integer). Validation ensures word_count within range and that the final length meets policy minimums.
Algorithms & Calculations: Sampling uses cryptographic RNG to pick words from the chosen list; entropy_estimate = word_count × log2(word_list_size). If digits and symbols added, approximate additional entropy is digits_count × log2(10) for digits and log2(symbol_set_size) for symbols.
Error & Edge Cases: If the custom word list has fewer than the requested word_count unique entries, the tool adjusts by allowing repetition or returns a warning. Missing required inputs triggers a validation error. External word lists may be unavailable; in such case, fall back to built-in list with a note in logs.
Industry/Region & Localization: Uses ASCII-compatible tokens; avoids locale-specific words for cross-region use; supports standard enterprise password policies; currencies not involved.
Assumptions & Exclusions: Assumes word lists are acceptable for security posture; excludes long-term password storage, integration with identity providers, or bulk credential export.