DHE-RSA-AES128-GCM-SHA256
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
DHE-RSA-AES128-GCM-SHA256 uses classic Diffie-Hellman (finite field) for key exchange instead of the elliptic curve variant. DHE provides forward secrecy but is significantly slower than ECDHE. It is acceptable but ECDHE variants are preferred. Required DHE group size is at least 2048 bits to be considered secure.
Key Exchange
DHE
Authentication
RSA
Encryption
AES-128-GCM
MAC / Integrity
SHA-256 (AEAD – integrated)
Details
DHE (Diffie-Hellman Ephemeral) over finite fields predates ECDHE and is slower. Performance degrades significantly with group sizes large enough for security (2048+ bits). ECDHE achieves equivalent security with smaller parameters and is universally preferred. DHE is still acceptable when clients don't support ECDHE, but this is rare in 2025+. Weak DH groups (768, 1024 bits) make this cipher insecure – see Logjam attack (2015).