Hi,
my code is:
InputStream rs = appearance.getRangeStream();
byte[] content = streamToByteArray(rs, 1024);
rs.close();
byte[] signedHashValue1 = server.sha1_rsa(content);
//===sha1 then rsa=========
byte[] hash = server.sha1(content);
byte[] signedHashValue2=server.rsa(hash);
//=========================
// add signed hash value into pdf
PdfPKCS7 sig = appearance.getSigStandard().getSigner();
sig.setExternalDigest(signedHashValue2, hash, "RSA");
PdfDictionary dic = new PdfDictionary();
dic.put(PdfName.CONTENTS,
new PdfString(sig.getEncodedPKCS1()).setHexWriting(true));
appearance.close(dic);
when I use signedHashValue1 , it's ok , I can get a valid signature in pdf;
but when I use signedHashValue2, get an error , says"Error encountered while
BER decoding".
public byte[] sha1(byte[] content) {
MessageDigest md;
md = MessageDigest.getInstance("SHA-1");
return md.digest(content);
}
public byte[] rsa(byte[] hash) {
Signature signature = Signature.getInstance("NONEwithRSA");
signature.initSign(this.privateKey);
signature.update(hash);
return signature.sign();
}
public byte[] sha1_rsa(byte[] content) {
Signature signature = Signature.getInstance("SHA1withRSA");
signature.initSign(this.privateKey);
signature.update(content);
return signature.sign();
}
If I use "SHA1withRSA" ,I will get an invalid signature says "document has
been modified"
--
Best Regards，
张健
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