pkcs7_get_signer_info() function

SignerInfo ::= SEQUENCE { version Version; issuerAndSerialNumber IssuerAndSerialNumber, digestAlgorithm DigestAlgorithmIdentifier, authenticatedAttributes [0] IMPLICIT Attributes OPTIONAL, digestEncryptionAlgorithm DigestEncryptionAlgorithmIdentifier, encryptedDigest EncryptedDigest, unauthenticatedAttributes [1] IMPLICIT Attributes OPTIONAL, Returns 0 if the signerInfo is valid. Return negative error code for failure. Structure must not contain vales for authenticatedAttributes and unauthenticatedAttributes.