Hi Victor, I solved a similar problem by letting iText do signature creation, get the hash value create a signature on my own. Later on I filled in the newly ceated signature into the preserverd siganture space. You have to take care that the area is big enough ...
Btw. : I'm not fimiliar with the RSACryptoServiceProvider object. What does the SignDate method do ? There is a pregenerated hash involved and a hash algo name. Does the name marks the algo used to generate the hash ? Or is this the hash algo used internally for signature creation ? Whether my mail helps or not, never mind to do a donation ;-) Greetings Andreas ----- Original Message ---- From: Victor <[email protected]> To: [email protected] Sent: Mon, April 26, 2010 1:48:46 PM Subject: [iText-questions] Sign PDF using SHA 256 Hi, Until now, I have used this code (http://itextpdf.sourceforge.net/howtosign.html#signextitextsharp2) to sign a PDF file using a digital certificate stored on Microsoft Store. The code is great, there is no problem with it if SHA1 is used. The problem is SignedCms class don't support SHA256 algorithm for smart cards or crypto tokens. Anyway, a SHA256 signature can be made using RSACryptoServiceProvider. RSACryptoServiceProvider rsaKey = new RSACryptoServiceProvider(); X509Certificate2 cert = GetCertificateFromMicrosoftStore(); rsaKey = cert.PrivateKey as RSACryptoServiceProvider; byte[] signature = rsaKey.SignData(documentHash, "SHA256"); The question is this: How I can add the RSA signature generated in advance by the RSACryptoServiceProvider to the PDF file in order to obtain a signed PDF. I have tried to use this code (http://itextpdf.sourceforge.net/howtosign.html#signextstd) but with no success (the error is "At least one signature requires validating - Internal cyptographyc library error"). Another method to solve the problem could be: How a PKCS#7 signed message can be created by using the signed data provided by the RSACryptoServiceProvider. If this will help the community, I am ready to make a PayPal donation for a solution. Thanks. Victor ([email protected]) ------------------------------------------------------------------------------ _______________________________________________ iText-questions mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/itext-questions Buy the iText book: http://www.itextpdf.com/book/ Check the site with examples before you ask questions: http://www.1t3xt.info/examples/ You can also search the keywords list: http://1t3xt.info/tutorials/keywords/ ------------------------------------------------------------------------------ _______________________________________________ iText-questions mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/itext-questions Buy the iText book: http://www.itextpdf.com/book/ Check the site with examples before you ask questions: http://www.1t3xt.info/examples/ You can also search the keywords list: http://1t3xt.info/tutorials/keywords/
