Increase the Secure Shell Minimum Recommended Diffie-Hellman Modulus Size to 2048 Bits
RFC 8270, “Increase the Secure Shell Minimum Recommended Diffie-Hellman Modulus Size to 2048 Bits”, is a Proposed Standard document published in December 2017 by L. Velvindron, M. Baushke. It updates RFC 4419. The canonical text is published by the RFC Editor.
Abstract
The Diffie-Hellman (DH) Group Exchange for the Secure Shell (SSH) transport-layer protocol specifies that servers and clients should support groups with a minimum modulus group size of 1024 bits. Recent security research has shown that the minimum value of 1024 bits is insufficient to protect against state-sponsored actors and any organization with enough computing resources. This RFC updates RFC 4419, which allowed for DH moduli less than 2048 bits; now, 2048 bits is the minimum acceptable group size.
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 8270 is hosted at rfc-editor.org. Available in TXT,HTML.
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