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Store encryption keys securely

Keys must never be hardcoded or committed to source control. Learn HSM, KMS, envelope encryption, and key derivation patterns for secure key storage.

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    The golden rule: never store encryption keys in plaintext alongside the data they encrypt. Options from most to least secure: HSM (hardware), KMS (cloud service), envelope encryption (master key wraps data keys), key derivation (derive from a password/passphrase).

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    PBKDF2 Key Derivation →

    Derive an encryption key from a user password using PBKDF2 with a high iteration count (100,000+). The salt must be random and stored separately. This is for user-controlled keys where no server-side storage exists.

  3. 3
    bcrypt Hash →

    Hash a master password with bcrypt for authentication. Note: bcrypt output is not suitable as an encryption key directly — use PBKDF2/scrypt for key derivation, bcrypt for password verification.

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    AES Encryptor →

    Use the derived key to encrypt data. The key never touches disk in plaintext — it exists only in memory during the encryption operation and is zeroed afterward.

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    For server-side applications, use a KMS (AWS KMS, GCP KMS, Azure Key Vault) or HSM. The master key never leaves the hardware; you call an API to encrypt/decrypt. For client-side, derive keys from user passwords with a strong KDF and store only the salt.

Frequently asked questions

Can I store a key in an environment variable?
Environment variables are better than hardcoding but still visible to anyone with process access (e.g., /proc/pid/environ on Linux). Use a KMS or secrets manager (Vault, AWS Secrets Manager) for production. Environment variables are acceptable for development only.
What is the difference between PBKDF2 and bcrypt?
PBKDF2 is a KDF that produces a key of any length — use it for encryption keys. bcrypt is a password hashing function with a fixed output — use it for password verification. They serve different purposes and are not interchangeable.

Workflows that solve this

AES encrypt then Base64 encode
Encrypt plaintext with AES and encode the ciphertext as Base64 for text-safe transport.
PIPELINE
Generate Password and Bcrypt Hash
Generate a random password then bcrypt-hash for auth systems.
PIPELINE
Generate password and hash with bcrypt
Generate a strong random password and immediately hash it with bcrypt for safe storage.
PIPELINE

Learn more

Want to understand why?

Choosing a hash algorithm: digests, password hashing, and MACs are three different jobs
A field guide to SHA-2, SHA-3, BLAKE2, MD5, bcrypt/Argon2, and HMAC — which one fits integrity checks, password storage, and message authentication, and why they are not interchangeable.
TUTORIAL
How to Derive Keys with PBKDF2
Derive a cryptographic key from a password using PBKDF2 with a high iteration count and salt.
TUTORIAL
Hash Salting
Hash salting is adding a random salt to the hash input so identical inputs produce different hashes, defeating rainbow tables and collision detection.
GLOSSARY
Key Derivation
Key derivation is the process of generating encryption keys from low-entropy passwords or high-entropy master keys, using KDFs (e.g., PBKDF2, scrypt, Argon2) to raise the cost of brute force.
GLOSSARY

Related tools

PBKDF2 Key Derivation
Derive a key from a password using PBKDF2 (RFC 2898) with Web Crypto API. Free, private, and 100% client-side.
TOOL
bcrypt Hash
Hash passwords with bcrypt or verify bcrypt hashes. Free, private, and 100% client-side.
TOOL
AES Encryptor
Encrypt text or binary data with AES (CBC/GCM/ECB) using Web Crypto API. Free, private, and 100% client-side.
TOOL