Extracting content from a P7M file

[paolo_romano2]

Did you ever tried extracting content from a PKCS7 signed file in ABAP to get

that *&%$ PDF document from it?

Well the solution is actually quite easy, and I would like to share it:

Download and install the BOUNCYCASTLE libraries from http://www.bouncycastle.org/latest_releases.html, taking care to download the ones which fit your JDK release; create a DC library project and deploy them on your SAP web application server, see this great blog to do that External Library Deployment and Usage in SAP NetWeaver Developer Studiohttp://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/60d99678-1a29-2d10-94b4-9d9a67b71...

Create a new Java Web Service using NWDS and use this code to decrypt the p7m signed file extracting the signed infos from it:

public String P7M_B64_Parser(String b64Docu) {           // TODO : Implement           //Base64 b64 = new Base64();           byte[] source = Base64.decode(b64Docu);           InputStream is = new ByteArrayInputStream(source);                     try{                                                    CMSSignedData sdp;                                  try {                                            sdp = new CMSSignedData(is);                                  } catch (final CMSException e) {                                            final IOException e1 = new IOException(                                                                "Error parsing PKCS7 content");                                            e1.initCause(e);                                            return "Error parsing PKCS7 content";                                  }                                 // final byte[] enco = sdp.getEncoded();                          CMSProcessable cmsp = sdp.getSignedContent();                          ByteArrayOutputStream bStream = new ByteArrayOutputStream();                          ObjectOutputStream oStream = new ObjectOutputStream( bStream );                          oStream.writeObject ( cmsp.getContent() );                          String result = new String(Base64.encode(bStream.toByteArray()));                          return  result;                     }                     catch(Exception e)                     {                                     }                                 return null;      }

However, the parameters are base64 encoded, so keep attention to encode/decode your source and result data.