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Is encrypt-then-MAC secure?
Of these three, only Encrypt-then-MAC is provably secure, in the sense of guaranteeing INT-CTXT (integrity of ciphertexts — it’s unfeasible for an attacker to construct a valid ciphertext other than those which he convinces the key holder to generate) and IND-CCA2 (indistinguishability under adaptive chosen ciphertext …
Why is encrypt-then-MAC Better?
In addition to protecting message integrity and confidentiality, authenticated encryption can provide security against chosen ciphertext attack. The encryption scheme is semantically secure under a chosen plaintext attack. The MAC function is unforgeable under a chosen message attack.
Does changing the order of encryption and Mac function modifies the MAC code?
The answer is YES. The MAC is applied to the data before encoding and encryption and therefore if the original bit is 1 the change in ciphertext will result in the same decrypted plaintext and then the MAC check will succeed.
When to use Encrypt-then-Mac instead of Mac?
On connecting, the client includes the encrypt_then_mac extension in its client_hello if it wishes to use encrypt-then-MAC rather than the default MAC-then-encrypt. If the server is capable of meeting this requirement, it responds with an encrypt_then_mac in its server_hello.
How does RFC 7366 Encrypt-then-Mac for Transport Layer Security?
RFC 7366 Encrypt-then-MAC for TLS and DTLS September 2014 Data (AEAD) ciphersuite, it MUST NOT send an encrypt-then-MAC response extension back to the client. Decryption reverses this processing.
Which is better Encrypt then Mac or TLS / DTLS?
The use of TLS/DTLS extensions to negotiate an overall switch is preferable to defining new ciphersuites because the latter would result in a Cartesian explosion of suites, potentially requiring duplicating every single existing suite with a new one that uses encrypt-then-MAC.
Is the Mac-then-encrypt mechanism a security vulnerability?
The MAC-then-encrypt mechanism has been the subject of a number of security vulnerabilities over a period of many years. Status of This Memo This is an Internet Standards Track document.