System for generating a cryptographic key from a memory used as a physically unclonable function

A method for generating a cryptographic key, the method comprising:

• powering-up of a memory used as a physically unclonable function, the memory being writable and volatile,
• allowing the memory to settle into a memory content which depends upon at least partially random physical characteristics of the memory,
• retrieving the memory content over a memory interface in a scrambled order,
• encrypting the memory by:
• receiving from me memory interface the memory content in the scrambled order,
• encrypting the received memory content, and
• writing back the encrypted memory content to the memory,
• decrypting the memory by:
• receiving from the memory interface the encrypted memory content in a linear or sequential pre-determined further order, and
• decrypting the received encrypted memory content to obtain the memory content in the pre-determined further order;
• and
• deriving a cryptographic key from the memory content into which the memory settled.

A non-transitory tangible computer readable storage medium comprising data loadable in a programmable apparatus, the data representing instructions executable by the programmable apparatus, said instructions being arranged to execute a method for generating a cryptographic key, the method comprising:

• powering-up of a memory used as a physically unclonable function, the memory being writable and volatile,
• allowing the memory to settle into a memory content which depends upon at least partially random physical characteristics of the memory,
• retrieving the memory content over a memory interface in a scrambled order,
• encrypting the memory by:
• receiving from me memory interface the memory content in the scrambled order,
• encrypting the received memory content, and
• writing back the encrypted memory content to the memory,
• decrypting the memory by:
• receiving from the memory interface the encrypted memory content in a linear or sequential pre-determined further order, and
• decrypting the received encrypted memory content to obtain the memory content in the pre-determined further order;
• and
• deriving a cryptographic key from the memory content into which the memory settled.