DH groups 1, 2, and 5 should no longer be used. These groups support a key size of 768 bits, 1024 bits, and 1536 bits, respectively.
DH groups 14, 15, and 16 use larger key sizes with 2048 bits, 3072 bits, and 4096 bits, respectively, and are recommended for use until 2030.
DH groups 19, 20, 21 and 24 with respective key sizes of 256 bits, 384 bits, 521 bits, and 2048 bits support Elliptical Curve Cryptography (ECC), which reduces the time needed to generate keys. DH group 24 is the preferred next generation encryption.
