RSA (Product): news timeline & CVEs

Researchers Found a New Way to Break RSA that Doesn’t Require Factoring the Key

Researchers demonstrated an oracle-assisted eNFS attack that forges 1,024-bit RSA signatures without factoring the modulus.

Researchers including Nadia Heninger and Emmanuel Thomé implemented eNFS, an oracle-assisted number-field-sieve method that can forge RSA signatures or decrypt ciphertexts without recovering the prime factors or private key. Their 1,024-bit demonstration used about 1,380 CPU core-years over five months and 232 queries to a raw unpadded RSA oracle, compared with an estimated 500,000 to one million core-years to factor the modulus. After a public-key precomputation, offline forgery costs about another 180 core-years. The attack needs temporary raw exponentiation access, such as certain PKCS#11 HSM operations or blind-signature protocols like Privacy Pass, and does not by itself break PKCS#1 v1.5 or RSA-PSS.

Cyber Security NewsSep 24, 17:48 UTC · 2d agoResearch 2 sources

Forging 1024-bit RSA signatures in nearly SNFS time

Researchers forged 1024-bit RSA signatures near SNFS speed using a signing oracle, without factoring the modulus.

An IACR ePrint paper implements the 2007 Joux–Naccache–Thomé algorithm to forge RSA signatures after temporary access to a raw signing or decryption oracle, without factoring the modulus. The authors report a 1024-bit demonstration totaling about 1380 CPU core-years, with cost close to the special number field sieve rather than the general number field sieve used for RSA key-size estimates. They argue practical signature security can be weaker than factoring-based guidance when such an oracle is available.

Lobsters · securitySep 24, 15:13 UTC · 2d agoResearch

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Researchers Found a New Way to Break RSA that Doesn’t Require Factoring the Key

Forging 1024-bit RSA signatures in nearly SNFS time