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simbiose / Encryption

Encryption is a simple way to encrypt and decrypt strings on Android and Java project.
MIT License
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Encrypted data is not authenticated / potential padding oracles #26

Open Vinc0682 opened 5 years ago

Vinc0682 commented 5 years ago

The encrypted data is not authenticated, thus allowing easy manipulation of the ciphertext with predictable changes to the plaintext. This is especially bad as unauthenticated AES-CBC often leads to padding oracle attacks which allow the recovery of the plaintext by an active adversary.

How to fix:

  1. Apply a secure message-authentication-code (MAC) like HMAC-SHA256 on the ciphertext and the IV. Always check the MAC BEFORE decrypting the ciphertext.

  2. Alternatively, use an AAD-Scheme like AES-GCM or ChaCha20-Ploy1305.

ademar111190 commented 4 years ago

Thank you for the information. Feel free to make a PR with the fix otherwise I'll study the topic when possible and implement the changes.