Saint ROCA, the Return of Coppersmith

Patron of electronic identity cards, Infineon TPM chips, and prime numbers that are too predictable.

Life

On 16 October 2017 researchers at Masaryk University in Brno revealed that the RSA library in Infineon chips generated primes with a recognisable structure. One look at a public key told you whether it was vulnerable, and Coppersmith's method could rebuild the private key, at a high cost but within reach of anyone with resources. TPMs, tokens and smart cards were affected, including about 750,000 Estonian identity cards, which had to be updated in a hurry.

Prayer

O Saint ROCA, who recognises keys by their shape, let our primes be chosen truly at random. Amen.

How to celebrate

Celebrated by updating the TPM firmware, regenerating keys and checking them with the discoverers' tool.

A prime with a pattern gives the game away.