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DHE (Diffie-Hellman Ephemeral)
Ephemeral Diffie-Hellman[405][406][407][408] is a variant of Diffie-Hellman[99][100][101][102][103] key exchange[133] protocol that has forward secrecy[127][128][129][130], and does protect past sessions against future compromises. If long-term secret keys or passwords are compromised, encrypted communications and sessions recorded in the past cannot be retrieved and decrypted. However, there is a protocol flaw called D(HE)at attack[581][582][583][584][585], a denial-of-service attack[586][587][588][589][590], which can be exploited effectively when large key sizes are enabled.
Always prefer cipher suites with PFS property over the non-PFS ones. Note that performance considerations implies preferring Ephemeral Elliptic-curve Diffie–Hellman[432][433] over Ephemeral Diffie-Hellman[405][406][407][408] and D(HE)at attack[581][582][583][584][585] implies using Diffie-Hellman ephemeral public key parameter[409][410][411]s with a size greater or equal than 2048 bits but less or equal than 4096 bits.
128
The symmetric key[185][186][187] withkey size[184] more than 128 bits as it is should be according to National Institute of Standards and Technology[470][471] so it is not vulnerable to preimage attack[67] and it cannreliably prove that message came from the stated sender (its authenticity) and has not been changed, so connection is not open for a man-in-the-middle attack[61].
Remove the cipher suite from the list of cipher suites supported by your server.
POLY1305
message authentication code[135][136][137][138] is a message authentication code based on universal hashing[150][151][152][153] which is considered secure. It provides authenticated encryption[74] which simultaneously assure the confidentiality[91][92][93] and authenticity[75][76][77] of data. Together with stream cipher[182][183] ChaCha20ChaCha20-Poly1305[328][329][330] gives better performance on mobile devices under the same conditions of security.
If your application or requirements specifically call for the use of a message authentication code[135][136][137][138] that does not provide authenticated encryption[74] prefer block cipher mode of operation[82][83][84][85][86] (eg: counter with CBC-MAC[32][33][34], Galois/Counter Mode[46][47][48][49] or message authentication code[135][136][137][138] (eg: Poly1305[458][459]) that proved authenticated encryption over the ones which does not provide it. In case of a hashed message authentication code[139][140][141][142][143][144][145] prefer message authentication code[135][136][137][138] based on Secure Hash Algorithm 2[212][213][214] over the ones based on Secure Hash Algorithm 1[202][203][204].
