What are the best ways to detect tampering in encrypted messages?

In the context of symmetric encryption, detecting tampering in encrypted messages primarily involves implementing cryptographic techniques such as Message Authentication Codes (MACs) and Authenticated Encryption. A MAC is a short piece of information used to authenticate a message and to provide integrity and authenticity assurances. It’s created by applying a MAC function to the message with a secret key and is then sent along with the message. The receiver, who also possesses the secret key, can generate a new MAC from the received message and compare it to the one sent. Any discrepancy indicates tampering.

🔒 Keeping encrypted messages safe from tampering is like fortifying a digital vault. I'd recommend using symmetric encryption with a message authentication code (MAC) or cipher block chaining (CBC) mode. These methods add extra layers of security, ensuring that any changes in the message are easily spotted. Asymmetric encryption, particularly digital signatures, is another great tool. They're like tamper-proof seals, showing if a message has been altered. To top it off, stick to strong encryption practices: use robust algorithms, secure keys, and protocols that verify message authenticity. 🛡️🔐

It’s not CBC *OR* a MAC!!!!! It’s a symmetric encryption scheme (e.g., CBC) **AND** a MAC. Alternatively, use authenticated encryption which natively includes both the symmetric encryption and the MAC. Let me just be clear: Whoever answered this would fail a serious cryptography class. LinkedIn, you have to do much better than this…

Detecting tampering in messages encrypted with symmetric encryption involves implementing mechanisms that ensure integrity and authenticity. One effective method is using cryptographic hash functions alongside the encryption process. By generating a hash of the original message before encryption and then verifying this hash upon decryption, any tampering during transit becomes evident as it alters the hash. Additionally, employing Message Authentication Codes (MACs) or HMACs (Hash-based Message Authentication Codes) with symmetric keys ensures that only parties with the correct key can authenticate the message, further securing against tampering.

Use asymmetric encryption and apply a digital signature. When the signature is applied a hash is generated. Validate the hash using the public key. If the hash doesn't validate, then the message has been tampered with.

The process works as follows: The sender encrypts the message with the recipient's public key and then creates a digital signature by encrypting a hash of the message with their own private key. This signature is sent along with the encrypted message. Upon receiving, the recipient decrypts the message using their private key. To verify the integrity of the message, the recipient decrypts the digital signature with the sender’s public key and compares the resulting hash with a fresh hash of the decrypted message. If the hashes match, it confirms that the message has not been tampered with and that it indeed originates from the claimed sender.

Detecting tampering in encrypted communications, particularly in contexts where security is paramount, requires a multifaceted approach that combines cryptographic techniques with advanced anomaly detection and network behavior analysis, Implementation of HMAC (Hash-based Message Authentication Code), Utilizing Advanced Encryption Standards. For certain applications using the Blockchain for critical communications, using a blockchain to store hashes of messages can provide a tamper-evident log. Any alteration in the message post its entry into the blockchain would be detectable due to the immutable nature of blockchain technology.

The core idea of this text is accurate, but the explanation is not. “A digital signature is a cryptographic hash that is encrypted with the sender's private key and attached to the message.” What? First, a digital signature doesn’t imply a hash. Second, many signature schemes (especially the ones used today) do not have any similarity to an “encryption” operation (that was RSA back in the day). Also, the “hybrid” (I’d argue that this is a wrong use of this word) protocol described here also can very well be malleable if not done right. LinkedIn, you need way higher standards…

QKD allows two parties to generate a shared, secret random key known only to them, which can then be used for encrypting and decrypting messages. The fundamental feature of QKD is that it is theoretically impossible for an eavesdropper to measure the quantum states in the key without disturbing those states in a detectable way. This is due to the Heisenberg Uncertainty Principle, which states that certain pairs of physical properties, like position and momentum, cannot both be measured exactly at the same time.

For tamper detection in post-quantum encryption scenarios, hash-based signatures can be particularly effective. These signatures use secure hash functions and are considered resistant to quantum attacks. When a message is sent, a hash of the message is created and then signed with the sender's private key using a hash-based signature scheme. The recipient, upon receiving the message, can verify the integrity of the message by using the sender's public key to check the signature. If the signature does not validate correctly against the message hash, it indicates that the message has been altered.

Secure communication: PQC can be used to protect sensitive data exchanged over the internet, such as financial transactions, medical records, and government communications. Digital signatures: PQC can be used to create digital signatures that guarantee the authenticity and integrity of electronic documents. Secure hardware: PQC can be implemented in hardware security modules (HSMs) to protect sensitive data stored on smart cards and other devices.

Everything discussed here is important - algorithm choice, block modes, integrity protection, etc. However, without proper key management it all falls apart. The gold standard for key protection is a hardware security module (HSM), preferably one with advanced features like key-enclave binding, attestation, etc. Techniques like client-side hashing, key stream precomputation, and enveloped encryption can keep performance strong. If an HSM is not available the next best options are short-lived keys that are securely wiped and keys that have protection from lower levels of the operating system and thus don't expose their raw bytes to applications. In some environments advanced techniques like key splitting and threshold schemes can be used.

Use Strong Encryption Standards: Opt for advanced encryption standards like AES (Advanced Encryption Standard) with a key size of at least 256 bits. For public-key cryptography, use algorithms and key lengths that are considered secure against current and foreseeable attacks, such as RSA with a key size of at least 2048 bits or ECC (Elliptic Curve Cryptography) with a key size of at least 256 bits. Regularly Update and Rotate Keys: Encryption keys should be changed regularly to prevent long-term exposure in case of a security breach. Implementing a key management policy that includes key rotation, key archiving, and destruction of old keys is crucial. Secure Key Stora

Sending messages between clients and providers can present an attack surface for encryption. The latest multi-party solutions will implement a Key ACL Service to authenticate users coming from an SSO Solution, from the general web, and to a 3rd party mail service. Client Side Encryption presents assured communications as a real path forward, and a best practice in my opinion.