Decrypt AES-GCM ciphertext

Verify and decrypt AES-GCM ciphertext without releasing unauthenticated plaintext.

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ToolAES-GCM Decrypt
Input
Output
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Preview

How it works

The ciphertext is separated from its tag and decrypted only after authentication succeeds against key, nonce, and associated data. Failed verification returns no trusted plaintext.

  • Verify-before-release prevents modification attacks.
  • 96-bit nonce and 128-bit tag match common interoperability.

Worked example

Decrypt Message
Decrypt AES-GCM ciphertext using the original password
Input
											Input: LIKc59NWLhbwrDtdmBCFq31YcTKxZRW23i++057nBdSjuSp3OvhR0Ah/PlUi43akz1AQpQdrAN1v67Is2X/68QD0nr0LjCcvlTveQ0JgWjQ/nZ1hWE+VvA==
Key: correct horse battery staple
Output
												The quick brown fox jumps over the lazy dog.

When to use this

Services, Web Crypto state, and protocol endpoints decrypt authenticated data.

Edge cases

  • A changed nonce fails authentication.
  • Wrong associated data fails even with intact ciphertext.
  • Truncated ciphertext or tag must be rejected.

References