gnuhealth-client/gnuhealth_crypto.patch

diff -U 6 -H -d -r -N -- a/gnuhealth-client/plugins/crypto/__init__.py b/gnuhealth-client/plugins/crypto/__init__.py
--- a/gnuhealth-client/plugins/crypto/__init__.py	1970-01-01 01:00:00.000000000 +0100
+++ b/gnuhealth-client/plugins/crypto/__init__.py	2014-07-15 10:33:53.000000000 +0200
@@ -0,0 +1,179 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    GNU Health: The Free Health and Hospital Information System
+#    Copyright (C) 2008-2014 Luis Falcon <lfalcon@gnusolidario.org>
+#    Copyright (C) 2011-2014 GNU Solidario <health@gnusolidario.org>
+#
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+
+import tryton.rpc as rpc
+from tryton.common import RPCExecute, warning, message
+from tryton.gui.window.form import Form
+import gettext
+
+try: 
+    import gnupg
+except:
+    warning(
+        ('Document Encryption / Signing disabled'
+         '\nPlease install the gnupg library '),
+        ('No GNU Privacy Guard library found !'),
+    )
+    
+    
+_ = gettext.gettext
+
+def sign_document(data):
+    """ Retrieve the hash value of the serialized document and
+        generates a clearsign signature using the user's private key
+        on the client side via GNU Privacy Guard - GPG -"""
+
+    gpg = gnupg.GPG()
+
+    document_model = data['model']
+
+    """ Don't allow signing more than one document at a time
+        To avoid signing unwanted / unread documents
+    """
+
+    if (len(data['ids']) > 1):
+        warning(
+            _('For security reasons, Please sign one document at a time'),
+            _('Multiple records selected !'),
+        )
+        return
+
+    """ Verify that the document handles digital signatures """
+
+    try:
+        record_vals = rpc.execute(
+            'model', document_model, 'read',
+            data['ids'],
+            ['document_digest', 'digital_signature'], rpc.CONTEXT)
+
+    except:
+        warning(
+            _('Please enable the model for digital signature'),
+            _('No Digest or Digital Signature fields found !'),
+        )
+        return
+
+    digest = record_vals[0]['document_digest']
+
+    """ Check that the document hasn't been signed already """
+
+    if record_vals[0]['digital_signature']:
+        warning(
+            _('Document already signed'),
+            _('This record has been already signed'),
+        )
+        return
+
+    try:
+        gpg_signature = gpg.sign(digest, clearsign=True)
+
+    except:
+        warning(
+            _('Error when signing the document'),
+            _('Please check your encryption settings'),
+        )
+
+    """
+    Set the clearsigned digest
+    """
+    try:
+        RPCExecute(
+            'model', document_model, 'set_signature',
+            data, str(gpg_signature))
+
+    except:
+        warning(
+            _('Error when saving the digital signature'),
+            _('The signature was generated but NOT saved !'),
+        )
+
+    else:
+        message(_('Document digitally signed'))
+
+        # TODO
+        # Reload the record view after storing the digital signature
+        # sig_reload or other method to check.
+        # a = Form(document_model, data['ids'])
+        # a.sig_reload()
+        # a.message_info(_('Document digitally signed'), color='blue')
+
+
+def verify_document(data):
+    """ Verify the digital signature of the document """
+
+    gpg = gnupg.GPG()
+
+    document_model = data['model']
+
+    """ Verify that the document handles digital signatures """
+
+    try:
+        record_vals = rpc.execute(
+            'model', document_model, 'read',
+            data['ids'],
+            ['document_digest', 'digital_signature'], rpc.CONTEXT)
+
+    except:
+        warning(
+            _('Please enable the model for digital signature'),
+            _('No Digest or Digital Signature fields found !'),
+        )
+        return
+
+
+    """ Verify signature """
+    digital_signature = record_vals[0]['digital_signature']
+
+    """ Check that the document has been signed """
+    if not digital_signature:
+        warning(
+            _('Unsigned document'),
+            _('This document has not been signed yet'),
+            )
+        return
+    
+    try:
+        verify_signature = gpg.verify(digital_signature)
+
+    except:
+        warning(
+            _('Error when verifying Digital Signature'),
+            _('Please check your GNU Privacy Guard Settings'),
+        )
+
+    else:
+        """ Show message of warning boxes depending on the verification """
+        if (verify_signature.valid):
+            message(_("Valid Signature !\n\n" + verify_signature.stderr))
+        else:
+            warning(
+                _(str(verify_signature.stderr)),
+                _(str("Error !")),
+            )
+
+
+def get_plugins(model):
+    return [
+        (_('Digitally Sign Document'), sign_document),
+        (_('Verify Digital Signature'), verify_document),
+    ]
diff -U 6 -H -d -r -N -- a/tryton/plugins/crypto/doc/index.rst b/tryton/plugins/crypto/doc/index.rst
--- a/tryton/plugins/crypto/doc/index.rst	1970-01-01 01:00:00.000000000 +0100
+++ b/tryton/plugins/crypto/doc/index.rst	2014-07-15 10:33:53.000000000 +0200
@@ -0,0 +1,33 @@
+Tryton Crytpo Plugin
+####################
+
+This plugin has been developed as part of GNU Health [1], but you should 
+be able to use it with any model in Tryton[2]
+
+Functionality :
+The Tryton crypto plugin interacts with GNU Privacy Guard [3] to digitally
+sign and encrypt documents.
+
+OS Requirements:
+
+Model attributes :
+The plugin requires - as a minimum - the following attributes on the model
+in order to be able to sign the document. 
+
+    "document_digest" of type fields.Char
+    "digital_signature" of type fields.Text 
+
+
+In real life, you will need others to make it meaningful. Please take a look
+at the Prescription model on the health_crypto module for an example and
+other fields used.
+
+
+
+Usage:
+
+References:
+
+1.- GNU Health : http://health.gnu.org
+2.- Tryton : http://www.tryton.org
+3.- GNU Privacy Guard : http://www.gnupg.org