What is the difference between a fully verifying signing device and partially verifying signing device?

A fully verifying signing device (FVSD) and a partially verifying signing device (PVSD) are two types of digital signature devices that differ in their level of verification of the signed data.

A FVSD performs a full verification of the signed data, including the message, signature, and the signer’s identity. This means that a FVSD will confirm that the message has not been altered since it was signed, that the signature is valid and was generated using the signer’s private key, and that the signer is who they claim to be. FVSDs provide a high level of security and are typically used in applications where the integrity and authenticity of the signed data are critical, such as in legal, financial, or government transactions.

In contrast, a PVSD performs only a partial verification of the signed data, typically only checking the validity of the signature itself. A PVSD does not verify the identity of the signer or the integrity of the signed data beyond what is necessary to confirm that the signature is valid. PVSDs are generally less secure than FVSDs, but they are also less expensive and can be used in applications where a lower level of security is acceptable, such as in non-critical business transactions.

Overall, the main difference between a FVSD and a PVSD is the level of verification they perform on the signed data, with FVSDs providing a higher level of security and assurance than PVSDs.