Signing system for validating stateful hash-based digital signatures

1. A signing system for validating stateful hash-based digital signatures, comprising at least one signing device, a logging device and a verifying device,

wherein each signing device is configured to:

receive data to be signed,

generate a hash-based digital signature comprising a one-time signature calculated for the data based on a one-time private key,

generate a one-time public key based on the one-time signature,

send the generated one-time public key to the logging device,

send the hash-based digital signature to the verifying device;

the verifying device is configured to:

generate a validation one-time public key based on the hash-based digital signature and the data, and

send the validation one-time public key to the logging device; and

the logging device is configured to:

store the generated one-time public key,

receive a validation one-time public key,

compare the validation one-time public key with all one-time public keys stored in the logging device,

provide a validation feedback signal to the verifying device, if the validation one-time public key coincides with exactly one stored one-time private key, and

provide a warning feedback signal, if the validation one-time public key does not coincide with exactly one stored one-time private key to the verifying device.

2. The signing system according to claim 1 , wherein the logging device comprises a logging unit storing the one-time public key and an auditing unit monitoring the stored one-time public keys in the logging unit.

3. The signing system according to claim 2 , wherein the auditing unit receives the validation one-time public key from the verifying device and provides the validation feedback signal or the warning feedback signal to the verifying device.

4. The signing system according to claim 3 , wherein the auditing unit notifies all verifying devices, which received the validation feedback signal, if the warning feedback signal is provided for any of the one-time public key stored in the logging device.

5. The signing system according to claim 3 , wherein the auditing unit passes the validation one-time public key received from the verifying device to the logging unit and passes the validation or warning feedback signal received from the logging unit to the verifying device.

6. The signing system according to claim 2 , wherein on receiving the generated one-time public key from the signing device in the logging unit, the logging unit or the auditing unit compares the generated one-time public key with all one-time public keys previously stored in the logging unit, and provides the validation feedback signal or the warning feedback signal to the auditing unit.

7. The signing system according to claim 2 , wherein on receiving the validation one-time public key from the verifying device, the auditing unit compares the validation one-time public key with the stored one-time public keys and provides the validation feedback signal or the warning feedback signal to the auditing unit.

8. The signing system according to claim 2 , wherein the auditing unit stores the validation one-time public key received from the verifying device and automatically provides the warning feedback signal if a warning feedback signal is received for the validation one-time public key at a later time.

9. The signing system according to claim 1 , wherein the signing device sends the hash-based digital signature and the data to be signed to the logging device, and the logging device generates the one-time public key based on the hash-based digital signature and the data.

10. The signing system according to claim 1 , wherein the logging device stores additional meta-information related to the hash-based digital signature received from the signing device and/or the logging device stores additional meta-information related to the verifying device received with the validation one-time public key from the verifying device.

11. The signing system according to claim 1 , wherein the logging device comprises more than one logging unit and/or more than one auditing unit.

12. A signing device for improved validation using stateful hash-based digital signatures, the signing device comprising at least one processor configured to:

receive data to be signed,

generate a hash-based digital signature comprising a one-time signature calculated for the data based on a one-time private key,

generate a one-time public key based on the one-time signature,

send the generated one-time public key to a logging device,

send the hash-based digital signature to a verifying device.

13. A method for validating stateful hash-based digital signatures, comprising:

in a signing device

receiving data to be signed,

generating a hash-based digital signature comprising a one-time signature calculated for the data based on a one-time private key,

generating a one-time public key based on the one-time signature,

sending the generated one-time public key to a logging device,

sending the hash-based digital signature to a verifying device, and

in the verifying device

generating a validation one-time public key based on the hash-based digital signature and the data,

sending the validation one-time public key to the logging device,

in the logging device

storing the generated one-time public key,

receiving the validation one-time public key,

comparing the validation one-time public key with all one-time public keys stored in the logging device,

providing a validation feedback signal to the verifying device, if the validation one-time public key coincides with exactly one stored one-time private key, and

providing a warning feedback signal, if the validation one-time public key does not coincide with exactly one stored one-time private key to the verifying device.

14. A computer program product, comprising a computer readable hardware storage device having computer readable program code stored therein, said program code executable by a processor of a computer system to implement the method of claim 13 .