Q: When I get signed PDFs back from a customer and check the digital signature using Adobe’s Appearance Integrity Report in the signature panel I get a list of error codes in the document. How can I fix this?
A: The Appearance Integrity Report analyzes the document and finds any items or features that could possibly alter the document without the user knowing. If you see any error codes it means that it is not guaranteed the user signed what they viewed.
One requirement (in some countries, by law) with digital signatures is that the signer signs what they see, and only what they see (this is the integrity of appearance). Many PDF features (such as Dynamic XFA forms, JavaScript, non-embedded fonts, etc…) can alter the appearance of a PDF document at any time, and that’s why the integrity of appearance is NOT ensured with any PDF that has any feature that could modify the document. The Appearance Integrity Report flags these to because in many cases they could not be considered legal as the user could have signed something they couldn’t see.
How to avoid this?
Make sure that the PDF Form can assure the integrity of appearance by removing or fixing any content that could modify the document. You can use the table below to determine what each error code means to correct the document.
Signature Report Error Codes
Dynamic features: Presentations, user-launched multimedia, JavaScript, dynamic forms, etc…
| String | Code | Description |
| Document contains hidden behavior | 1000 | The document contains hidden actions that may not be intended or known by the end user. Actions include JavaScript actions (document open, save, etc.), playing multimedia, executing a menu item, and so on. |
| Comment or form field may silently change | 1001 | The document contains non-signature form fields. Such fields’ visual appearances may change based on external variables. |
| Comment or form field may silently change | 1002 | The document contains comments. Comments’ visual appearances may change based on external variables. |
| Document may silently launch menu items | 1003 | The document contains named actions that may launch menu items without the user’s knowledge. |
| Presentation elements may change appearance | 1004 | Presentations are not allowed since a presentation may contain animations or other elements that may change document appearance or behavior. |
| The document contains a dynamic form | 1005 | XFA-based (dynamic forms) documents are not allowed since such forms could alter the document’s appearance or behavior. |
| Document contains links to external PDFs | 1006 | The document links to external PDFs on the Internet, file system, or network and it has no control over the nature of that linked content. Embedded Go-To actions must not refer to external hierarchies. |
| Comment or form field may silently change | 1007 | Disallowed annot type: <annot type>. One or more form fields are associated with a 3D object, file attachment, multimedia, or other dynamic objects. |
| Document contains hidden behavior | 1008 | Disallowed action type: <action type>. The document contains hidden actions that may not be intended or known by the end user. Actions include JavaScript actions (document open, save, etc.), playing multimedia, executing a menu item, and so on. |
| Document contains hidden behavior | 1009 | The document’s content is divided into layers that can be silently displayed or hidden on the fly. |
PDF content with variable rendering: JavaScript, non-embedded fonts, etc…
| String | Code | Description |
| Page content may silently change | 2004 | Visual elements may change based on external variables. For example, a logo may change color based on time or zoom level. No postscript XObjects allowed. |
| Document may not | 2006 | Some or all of the content is encrypted and the encryption method is not available in |
| open in the future | standard Acrobat installations. For example, the document may be protected by the | |
| Adobe Policy Server. Document contain streams encrypted using crypt filter. | ||
| Page content may | 2007 | The document author has enabled image interpolation. No image interpolation is |
| silently change | allowed. | |
| Page content may | 2009 | The document uses a PDF transfer function that interprets and replaces color. For |
| silently change | example, it could replace black with white. Extended graphic state should not use the TR | |
| key | ||
| Page content may | 2010 | The document uses a PDF transfer function that interprets and replaces color. For |
| silently change | example, it could replace black with white. If present, the extended graphic state’s TR2 | |
| key must be set to default | ||
| Page content may | 2011 | The document’s extended graphic state uses the FL key. The key is a number that |
| silently change | indicates how much flatness tolerance should exist when drawing objects. Content may | |
| display differently from Acrobat to other applications | ||
| Page content may | 2012 | Image XObject must not contain an alternate version |
| silently change | ||
| Text appearance may silently change | 2013 | Document contains non-embedded fonts. When the document opens on a system that does not have the requisite fonts, Acrobat will replace them with some other font. Users should always turn on font-related warnings. |
| Text appearance may silently change | 2014 | Disallowed font type: <font type>. True type and TrueType-based OpenType fonts are not allowed because they are programs and may change the document’s appearance based on external variables. |
External content: Hyperlinks, alternate images, linked files, etc…
| String | Code | Description |
| Document links to external content | 3000 | Document links to images not in the PDF. No external XObjects allowed. |
| Document links to external content | 3001 | Document links to images not in the PDF that are used as alternates. For example, an alternate, high resolution images might be specified for printing. Images must not contain an OPI alternate version. |
| Document links to external content | 3002 | Document contains external streams. The author has flagged some PDF bytes as a stream which may get data from an external source. |
| Document links to external content | 3003 | Document links to images not in the PDF that are used as alternates. For example, an alternate, high resolution images might be specified for printing. Form XObject must not contain an OPI alternate version. |
Uncategorized content: Unrecognized or malformed PDF
| String | Code | Description |
| Unrecognized PDF content | 4000 | Unrecognized PDF content: The document contains PDF content or custom content not supported by the current version of Acrobat. The document may have been created by a later version of Acrobat. |
| Page content may silently change | 4001 | Unrecognized drawing operator: The document contains PDF content or custom content not supported by the current version of Acrobat. The document may have been created by a later version of Acrobat. |
| PDF content contains errors | 4002 | Malformed drawing instructions: Syntax error. Page content violates the grammar for page content definition. For example, the instruction might specify drawing a square but the syntax for doing it is incorrect. |
