Java.security：在RSA签名恢复之前填充00字节。它从何而来？

I'm working on a project that needs to perform a digital signature on a plaintext. To do so, I perform a RSA decryption (with the private key) on the ciphertext. To verify the signature I compute the RSA encryption (using the Public Key) of the signature and compare it with the initial ciphertext. If it's the same, the signature is valid. (this is basically a signaute with recovery).I'm working on a project that needs to perform