Encoder / Decoder

Encrypt and decrypt strings with your own key or the built-in default.

Setup

Pick an algorithm and key. AES + libsodium outputs are wrapped in a JSON envelope so they are easy to store and share. CryptoJS outputs use the OpenSSL salted Base64 format.

Algorithm

Key / Passphrase

For AES + libsodium modes, the passphrase is stretched with PBKDF2 (210,000 iterations, SHA-256) to make brute force attacks harder.

Plaintext

Envelope format (AES + libsodium)

AES + libsodium outputs are stored in a JSON envelope containing the algorithm, salt, IV or nonce, and ciphertext. CryptoJS outputs are OpenSSL-style Base64 strings and do not use this envelope.

{
  "v": 1,
  "alg": "AES-GCM",
  "iter": 210000,
  "salt": "...",
  "iv": "...",
  "ct": "...",
  "format": "base64"
}

Algorithm guide

AES-GCM (Recommended)

Authenticated encryption that provides confidentiality and tamper detection in one step.

Engine: Web Crypto

Key: 256-bit key derived from your passphrase using PBKDF2 (SHA-256).

IV / Nonce: 12-byte nonce; must be unique per encryption.

Output: Ciphertext plus authentication tag (combined by Web Crypto).

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Most general-purpose app data encryption.

Notes:

Fast and widely supported in modern browsers.
If the nonce repeats with the same key, security breaks.
Decrypt fails if ciphertext or tag is modified.

AES-CBC

Classic block cipher mode that provides confidentiality but no integrity.

Engine: Web Crypto

Key: 256-bit key derived from your passphrase using PBKDF2 (SHA-256).

IV / Nonce: 16-byte IV; must be random and unique.

Output: Ciphertext with padding; integrity is not provided.

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Legacy compatibility or learning purposes.

Notes:

Requires a separate MAC (not included here) for integrity.
Padding makes it larger than plaintext.
Avoid for new designs unless you add authentication.

AES-CTR

Stream-like mode that turns AES into a keystream; encryption and decryption are symmetric.

Engine: Web Crypto

Key: 256-bit key derived from your passphrase using PBKDF2 (SHA-256).

IV / Nonce: 16-byte counter block; counter portion must never repeat.

Output: Ciphertext only; integrity is not provided.

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Streaming data where authentication is handled separately.

Notes:

Very fast and parallelizable.
Never reuse a counter with the same key.
Pair with a MAC for integrity.

XChaCha20-Poly1305 (libsodium)

Modern AEAD cipher with a long nonce, providing confidentiality and integrity.

Engine: libsodium-wrappers

Key: 32-byte key derived from your passphrase using PBKDF2 (SHA-256).

IV / Nonce: 24-byte nonce; must be unique per encryption.

Output: Ciphertext with Poly1305 authentication tag (combined).

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Large-scale apps that want a modern AEAD with a roomy nonce.

Notes:

Nonce is longer than ChaCha20-Poly1305, reducing collision risk.
Widely recommended for new designs in the libsodium ecosystem.
Tampering causes decryption to fail.

ChaCha20-Poly1305 (libsodium)

Fast AEAD cipher with strong security and great performance on mobile.

Engine: libsodium-wrappers

Key: 32-byte key derived from your passphrase using PBKDF2 (SHA-256).

IV / Nonce: 12-byte nonce; must be unique per encryption.

Output: Ciphertext with Poly1305 authentication tag (combined).

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Performance-focused encryption across browsers and devices.

Notes:

Excellent performance without AES hardware acceleration.
Nonce reuse with the same key breaks security.
Tampering causes decryption to fail.

Secretbox (XSalsa20-Poly1305)

libsodium's classic secret-key API with strong confidentiality and integrity.

Engine: libsodium-wrappers

Key: 32-byte key derived from your passphrase using PBKDF2 (SHA-256).

IV / Nonce: 24-byte nonce; must be unique per encryption.

Output: Ciphertext with authentication tag (combined).

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Simple, reliable symmetric encryption with libsodium.

Notes:

Built for misuse resistance, but nonce reuse is still dangerous.
Well-audited and widely adopted.
Tampering causes decryption to fail.

AES-CBC (CryptoJS)

AES-CBC via CryptoJS with OpenSSL-style salted output.

Engine: crypto-js

Key: Passphrase-based key derivation handled by CryptoJS (OpenSSL-style).

IV / Nonce: Random IV generated by CryptoJS.

Output: Base64 OpenSSL format string (starts with Salted__).

UTF-8: Plaintext is handled as UTF-8 by CryptoJS.

Best for: Interoperability with OpenSSL-style AES outputs.

Notes:

Provides confidentiality but no integrity checks.
Use only for compatibility needs; prefer AEAD modes for new work.
Output includes salt and IV data internally.

TripleDES (CryptoJS)

Legacy 3DES encryption for compatibility with older systems.

Engine: crypto-js

Key: Passphrase-based key derivation handled by CryptoJS.

IV / Nonce: Random IV generated by CryptoJS.

Output: Base64 OpenSSL format string (starts with Salted__).

UTF-8: Plaintext is handled as UTF-8 by CryptoJS.

Best for: Legacy systems that require 3DES.

Notes:

Significantly slower than AES.
Smaller security margin than modern ciphers.
Only use when required for compatibility.

DES (CryptoJS)

Very old block cipher kept only for legacy compatibility.

Engine: crypto-js

Key: Passphrase-based key derivation handled by CryptoJS.

IV / Nonce: Random IV generated by CryptoJS.

Output: Base64 OpenSSL format string (starts with Salted__).

UTF-8: Plaintext is handled as UTF-8 by CryptoJS.

Best for: Legacy compatibility demos only.

Notes:

DES is no longer considered secure.
Use only for teaching or legacy data.

RC4 (CryptoJS)

Legacy stream cipher for compatibility use cases.

Engine: crypto-js

Key: Passphrase-based key derivation handled by CryptoJS.

IV / Nonce: No IV required.

Output: Base64 OpenSSL format string (starts with Salted__).

UTF-8: Plaintext is handled as UTF-8 by CryptoJS.

Best for: Legacy systems only.

Notes:

RC4 is considered insecure and deprecated.
Avoid for any new designs.

RC4Drop (CryptoJS)

RC4 with initial keystream dropped; still legacy.

Engine: crypto-js

Key: Passphrase-based key derivation handled by CryptoJS.

IV / Nonce: No IV required.

Output: Base64 OpenSSL format string (starts with Salted__).

UTF-8: Plaintext is handled as UTF-8 by CryptoJS.

Best for: Legacy compatibility experiments.

Notes:

Still based on RC4, which is considered weak.
Only keep for compatibility with old formats.

Rabbit (CryptoJS)

Stream cipher from the eSTREAM project; mostly for legacy use.

Engine: crypto-js

Key: Passphrase-based key derivation handled by CryptoJS.

IV / Nonce: Optional IV handled by CryptoJS.

Output: Base64 OpenSSL format string (starts with Salted__).

UTF-8: Plaintext is handled as UTF-8 by CryptoJS.

Best for: Legacy compatibility with Rabbit-based data.

Notes:

Not widely used in modern systems.
Prefer modern AEAD modes instead.

Simple XOR (Not secure)

Lightweight obfuscation using XOR with your key, then Base64 encoding.

Engine: Built-in

Key: Any passphrase; repeated across data bytes.

IV / Nonce: No IV or nonce.

Output: Base64 text.

UTF-8: Plaintext is encoded as UTF-8. For binary data, Base64-encode it first.

Best for: Quick obfuscation, demos, or teaching concepts.

Notes:

Easy to reverse if the key is weak or reused.
Provides no authentication or integrity.
Do not use for sensitive data.