Manipulation-proof storage of evidence-relevant data

1. A method for manipulation-proof storage of payload data, comprising:

storing the payload data in a chain of data records;

forming, for each data record in the chain, a current hash value at least using the payload data comprised in the respective data record, and storing the current hash value in the respective data record;

storing, in said each data record, a predecessor hash value that corresponds to a hash value of a preceding data record, wherein, in a first data record in the chain, a predetermined root hash value replaces the predecessor hash value;

storing, in a persistent memory, a chain of hash values including the current hash value, the predecessor hash value, and the predetermined root hash value, such that content, once stored in the persistent memory, is no longer modifiable or removable from the persistent memory after the fact and that the content of the persistent memory allows no conclusion as to the payload data itself; and

storing the data records in a reversible memory that is distinct from the persistent memory,

wherein the data records are created by a first delivering device,

wherein the storing of the chain of hash values in the persistent memory is performed by a second safekeeping device,

wherein the first delivering device is a field device disposed in a direct relationship with an industrial production process,

wherein the payload data comprises measurement values of at least one sensor that is disposed in the field device or is connected to the field device, and

wherein the delivering device is a fill level gauge, a limit level gauge, a density meter, a flow meter, or a pressure gauge.

2. The method according to claim 1 , wherein at least one of the hash values in the chain of hash values is stored in the chain together with a time stamp, and/or the payload data of at least one data record comprises a time stamp.

3. The method according to claim 1 , wherein, for at least one data record, the payload data and/or a current hash value of the at least one data record are signed with a private cryptographic key, and a signature is incorporated into the at least one data record.

4. The method according to claim 1 , wherein the current hash value is formed at least over a combination of the payload data and the predecessor hash value.

5. The method according to claim 1 ,

wherein the second safekeeping device transmits the predecessor hash value to the first delivering device over a bidirectional communications link, and

wherein the first delivering device creates a respective next data record using the predecessor hash value and transmits the respective next data record to the second safekeeping device.

6. The method according to claim 1 , wherein the persistent memory is a memory having an irreversible physical writing process.

7. The method according to claim 1 , wherein the persistent memory is a distributed blockchain memory in which content is updated by a consensus of a plurality of participants.

8. A non-transitory computer-readable storage medium having machine-readable instructions stored therein, which, when executed on a computer or on an embedded system, upgrades the computer or the embedded system to a safekeeping device and/or a delivering device, and instructs the safekeeping device and/or the delivering device to perform the method according to claim 1 .

9. A system for manipulation-proof storage of payload data, the system comprising a safekeeping device and a delivering device,

the safekeeping device comprising:

a first interface configured to connect to a field device as the delivering device, wherein the field device is disposed in a direct relationship with an industrial production process;

a second interface configured to connect to a reversible memory;

a third interface configured to connect to a persistent memory, wherein content, once stored in the persistent memory, can neither be changed nor removed from the persistent memory after the fact and the content of the persistent memory allows no conclusion as to the payload data itself; and

a first logic circuit configured to:

receive at least one data record from the delivering device, wherein payload data in this record comprises measurement values of at least one sensor that is comprised in the field device or connected to the field device,

verify a cryptographic signature comprised in the at least one data record with a public key associated with the delivering device, and

transmit the at least one data record to the reversible memory upon a positive outcome of the verification,

retrieve predecessor hash values from the persistent memory and transmit the retrieved predecessor hash values to the delivering device,

store the data records in the reversible memory, and

store current hash values from the at least one data record received from the delivering device in the persistent memory, so that, in the persistent memory, a chain of hash values is stored including a current hash value, a predecessor hash value, and a predetermined root hash value; and

the delivering device comprising:

a memory configured to store a private cryptographic key;

a first interface configured to connect to the safekeeping device;

a sensor and/or a second interface configured to connect to a sensor; and

a second logic circuit configured to:

capture measurement values of one or more sensors as the payload data and combine the captured measurement values of the one or more sensors with the predecessor hash value obtained from the safekeeping device,

create the current hash value using a combination of the payload data with the predecessor hash value,

create a signature of the current hash value with the private cryptographic key, and

combine the payload data, the current hash value, the signature, and the predecessor hash value into a data record and transmit the data record to the safekeeping device,

wherein the delivering device is a fill level gauge, a limit level gauge, a density meter, a flow meter, or a pressure gauge.

10. The system according to claim 9 , wherein the first interface is further configured as a two-conductor line or as a radio link that is limited to a transmit duty cycle of at most 10%.

11. The system according to claim 9 , wherein the third interface is configured as a client configured to integrate the safekeeping device as a full participant into a blockchain network serving as the persistent memory.