Factoring as a Service

Luke Valenta; Shaanan Cohney; Alex Liao; Joshua Fried; Satya Bodduluri; Nadia Heninger

Paper 2015/1000 Original: eprint.iacr.org/2015/1000 ↗

Factoring as a Service

Luke Valenta

Shaanan Cohney

Alex Liao

Joshua Fried

Satya Bodduluri

Nadia Heninger

Abstract

The difficulty of integer factorization is fundamental to modern cryptographic security using RSA encryption and signatures. Although a 512-bit RSA modulus was first factored in 1999, 512-bit RSA remains surprisingly common in practice across many cryptographic protocols. Popular understanding of the difficulty of 512-bit factorization does not seem to have kept pace with developments in computing power. In this paper, we optimize the CADO-NFS and Msieve implementations of the number field sieve for use on the Amazon Elastic Compute Cloud platform, allowing a non-expert to factor 512-bit RSA public keys in under four hours for \$75. We go on to survey the RSA key sizes used in popular protocols, finding hundreds or thousands of deployed 512-bit RSA keys in DNSSEC, HTTPS, IMAP, POP3, SMTP, DKIM, SSH, and PGP.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
History: 2016-01-16: last updated; 2015-10-15: published
Short URL: https://ia.cr/2015/1000
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2015/1000,
      author = {Luke Valenta and Shaanan Cohney and Alex Liao and Joshua Fried and Satya Bodduluri and Nadia Heninger},
      title = {Factoring as a Service},
      howpublished = {Cryptology {ePrint} Archive, Paper 2015/1000},
      year = {2015},
      url = {https://eprint.iacr.org/2015/1000}
}