Review

Cipher.init may throw InvalidKeyException.

Add try/catch and fallback handling.

• missing/exception handling

com/itextpdf/text/pdf/PdfPublicKeySecurityHandler.java

computeRecipientInfo(X509Certificate, byte[])

class PdfPublicKeySecurityHandler {
    private KeyTransRecipientInfo computeRecipientInfo(X509Certificate x509certificate, byte[] abyte0)
        throws GeneralSecurityException, IOException
    {
        ASN1InputStream asn1inputstream =
            new ASN1InputStream(new ByteArrayInputStream(x509certificate.getTBSCertificate()));
        TBSCertificateStructure tbscertificatestructure =
            TBSCertificateStructure.getInstance(asn1inputstream.readObject());
        AlgorithmIdentifier algorithmidentifier = tbscertificatestructure.getSubjectPublicKeyInfo().getAlgorithmId();
        IssuerAndSerialNumber issuerandserialnumber =
            new IssuerAndSerialNumber(
                tbscertificatestructure.getIssuer(),
                tbscertificatestructure.getSerialNumber().getValue());
        Cipher cipher = Cipher.getInstance(algorithmidentifier.getObjectId().getId());
        cipher.init(1, x509certificate);
        DEROctetString deroctetstring = new DEROctetString(cipher.doFinal(abyte0));
        RecipientIdentifier recipId = new RecipientIdentifier(issuerandserialnumber);
        return new KeyTransRecipientInfo( recipId, algorithmidentifier, deroctetstring);
    }

}