Increase minimum recommended modulus size to 2048 bits

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Last updated 2017-10-20 (latest revision 2017-04-18)
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The Diffie-Hellman (DH) Group Exchange for the Secure Shell (SSH) Transport layer Protocol specifies that servers and clients should support groups with a modulus length of k bits, where the recommended minumum value is 1024 bits. Recent security research has shown that a minimum value of 1024 bits is insufficient against state-sponsored actors. As such, this document formally updates RFC 4419 [RFC4419] such that the minimum recommended value for k is 2048 bits and the group size is 2048 bits at minimum.


Loganaden Velvindron (

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