ChaCha20 Poly1305 (AEAD) Encrypt Decrypt Online

ChaCha20-Poly1305 provides authenticated encryption (confidentiality + integrity). This runs entirely in your browser. Do not reuse key+nonce pairs.

Mode:

Expected: 64 hex chars (32 bytes)

Expected: 24 hex chars (12 bytes)

AAD is authenticated but not encrypted. Include protocol headers, filenames, etc., if required.

Characters: 0

Result will appear here…
Tag (HEX)
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Preview (first 128 chars)
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Security Notes & Best Practices

ChaCha20-Poly1305 is an AEAD cipher providing both confidentiality and integrity. The one-time Poly1305 key is derived from the ChaCha20 counter=0 block.

  • • NEVER reuse the same key+nonce pair for multiple messages.
  • • Use secure random nonces or unique counters to ensure uniqueness.
  • • Keep keys secret and use secure random generation where possible.
  • • Consider a header format for files (nonce + tag + ciphertext).

Supported features

  • • ChaCha20-Poly1305 AEAD (RFC 8439) — encrypt & verify
  • • AAD support
  • • Key/nonce HEX or UTF-8 inputs + secure random generation
  • • Text + File processing (in-browser)
  • • Copy, Download, Paste, Toast notifications