About PKCS#1 Signatures

The PKCS#1 conventional facilitates a amount of public-key cryptographic algorithms and digest methods, which include RSA encryption, DSA signatures, and SHA-1 and MD5 digests (see the Bibliography for references). For signing pdf file records making use of PKCS#1, the only suggested worth of SubFilter is adbe.x509.rsa_sha1, which utilizes the RSA encryption algorithm and SHA-1 digest method. The certificate chain in the signer is saved inside the Cert entry. You can see also here.