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    "# Password Hashing\n",
    "\n",
    "Secret keys used to encrypt or sign confidential data have to be chosen from a very large keyspace.\n",
    "\n",
    "However, passwords are usually short, human-generated strings, making dictionary attacks practical.\n",
    "\n",
    "Password hashing functions derive a secret key of any size from a password and salt.\n",
    "\n",
    "  - The generated key has the size defined by the application, no matter what the password length is.\n",
    "  - The same password hashed with the same parameters will always produce the same output.\n",
    "  - The same password hashed with different salts will produce different outputs.\n",
    "  - The function deriving a key from a password and salt is CPU intensive and intentionally requires a fair amount of memory. Therefore, it mitigates brute-force attacks by requiring a significant effort to verify each password.\n",
    "  \n",
    "Common use cases:\n",
    "\n",
    "  - Password storage, or rather storing what it takes to verify a password without having to store the actual password.\n",
    "  - Deriving a secret key from a password; for example, for disk encryption.\n",
    "  \n",
    "Sodium's high-level crypto_pwhash_* API currently leverages the Argon2id function on all platforms. This can change at any point in time, but it is guaranteed that a given version of libsodium can verify all hashes produced by all previous versions from any platform. Applications don't have to worry about backward compatibility."
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