PDF 2.0 (ISO 32000-2): Existing Acrobat Features

The PDF 2.0 features discussed below are not completely new, but have already been introduced with earlier Acrobat versions.

Acrobat 9 Features

The following features have been implemented in Acrobat 9 (2008) and are specified in PDF 1.7 Adobe Extension Level 3:

Multimedia content such as sound and video can be stored in RichMedia annotations and played with actions of type RichMediaExecute. RichMedia annotations support the interaction and combination of sound, video, and 3D artwork (samples).

2D and 3D geospatial data can be added so that page content can be registered geospatially. Geospatial reference data defines the relationship of page contents and geographic regions using one of several common geospatial models of the earth (samples). Although PDF 1.7 Extension Level 3 and PDF 2.0 allow geospatial information to be attached to a page, an image or a Form XObject, Acrobat DC and below support geospatial data only on the page level.

Support for 3D artwork in U3D format is already available in PDF 1.7, while PDF 2.0 adds support for 3D artwork in the PRC format according to ISO 14739-1:2014. PRC support has been added in Acrobat 8.1.

Projection annotations store measurements and comments for 3D annotations.

PDF collections (portfolios) are already available in PDF 1.7. Acrobat 9 added support for nested folders and a Flash-based navigator (samples). While hierarchical collections are part of PDF 2.0, Flash-based navigators are not supported; they have been replaced with a set of predefined (named) navigators such as navigators for a tiled view, a strip of thumbnails, or a tree-like presentation.
File attachments may be assigned a thumbnail image.

Acrobat 9 extended AES encryption to support Unicode passwords and 256-bit keys. Unicode passwords are part of PDF 2.0. However, due to shortcomings in the password handling the Acrobat 9 algorithm is not included in PDF 2.0 (see here for more information).

Acrobat 9 also introduced barcode fields which are text fields containing dynamic barcodes in the formats PDF417, Data Matrix or QR code (sample). However, barcode fields are not included in PDF 2.0.

Acrobat X Features

The features below have been implemented in Acrobat X (2010) which formally creates documents according to PDF 1.7 Adobe Extension Level 8. However, Adobe never published the specification of Extension Level 8:

The existing AES-based encryption has been overhauled to fix the security flaws found in the Acrobat 9 algorithm. The method for deriving the file encryption key from the user password is different than the one in Acrobat 9. While Acrobat X supports AES-128 and AES-256, PDF 2.0 deprecates the use of AES-128 and encourages only AES-256.

Digital signatures according to the PAdES standards ETSI TS 102 778 and ETSI EN 319 142; see here for more information. PAdES includes improvements to the actual signature by protection against a threat scenario called certificate substitution, support for the Document Security Store (DSS) which can be used to attach validation material to a signed PDF document, as well as document time-stamps and long-term validation (LTV).

Acrobat XI Features

The following features have been specified in individual documents and implemented in Acrobat XI (2012):

Digital signatures have previously been limited to the RSA and DSA signature schemes. Acrobat XI introduced support for signatures according to Elliptic Curve Cryptography (ECC). Acrobat XI and DC support only the three most common elliptic curves recommended by NIST, namely P-256, P-384, and P-521 (list of algorithms supported in Acrobat). Other common elliptic curves including the remaining twelve curves recommended by NIST (RFC 5480), Brainpool curves (RFC 5639), and the modern Curve25519 (RFC 7748) are not supported in Acrobat. While PDF 2.0 includes ECC signatures, it doesn’t specify the set of supported curves, opening potential incompatibilities regarding signature validation.

Acrobat XI and above support Elliptic Curve Cryptography (ECC) for public key encryption, also called certificate security (list of algorithms supported in Acrobat). See also certificate security. The only symmetric algorithm for use in certificate security endorsed by PDF 2.0 is AES-256. All other algorithms supported in earlier PDF and Acrobat versions are declared as deprecated, including DES, Triple-DES, AES-128 and AES-192.

Unfortunately, a modern cryptographic scheme for authenticated encryption with Galois Counter Mode (GCM, standardized as NIST 800-38D in 2007) is not supported in PDF 2.0. In a similar vein, the so-called Bleichenbacher attack poses a well-known threat for RSA-based encryption schemes. An improved padding method called Optimal Asymmetric Encryption Padding (OAEP according to PKCS#1 version 2.1 in RFC 3447) thwarts the Bleichenbacher attack. However, PDF 2.0 doesn’t clarify whether or not RSA-OAEP is supported since it references RFC 5652 where RSA-OAEP is optional.