Cryptographic key production from a physical unclonable function

An electronic cryptographic method for determining a cryptographic key, the electronic cryptographic method comprising:

• an enrollment phase including
• producing a first noisy bit string using a physically unclonable function, and
• determining debiasing data from the first noisy bit string for reducing bias in the first noisy bit string, the debiasing data marking bits in the first noisy bit string as retained or discarded;
• and
• the reconstruction phase including
• producing a second noisy bit string using the physically unclonable function, and
• determining the cryptographic key from bits in the second noisy bit string marked as retained by the debiasing data, the cryptographic key being independent from bits in the second noisy bit string marked as discarded by the debiasing data.

A non-transitory tangible computer readable storage medium including data loadable in a programmable apparatus, the data representing instructions executable by the programmable apparatus, the instructions comprising:

• one or more obtaining instructions configured to obtain a first noisy bit string from a physically unclonable function;
• one or more determining instructions configured to determine debiasing data from the first noisy bit string for reducing bias in the first noisy bit string, the debiasing data marking bits in the first noisy bit string as retained or discarded,
• one or more obtaining instructions configured to obtain a second noisy bit string from the physically unclonable function;
• and
• one or more determining instruction to determine the cryptographic key from bits in the second noisy bit string marked as retained by the debiasing data, the cryptographic key being independent from bits in the second noisy bit string marked as discarded by the debiasing data.