T 1288/09 (Detecting unauthorized transmission/AUDIBLE MAGIC) of 18.4.2013

Summary of Facts and Submissions

I. The appeal lies against the decision of the examining division, dispatched on 20 January 2009, to refuse Eu ro pean patent application no. 02725522.3 in view of, in particular, the follow ing document:

D2: WO 96/36163 A2

The decision concluded that the then main and first auxil iary requests did not comply with Article 123 (2) EPC and that the then second and third auxiliary requests lacked an inventive step, Article 56 EPC 1973, over D2 in view of common knowledge in the art. To establish the common knowledge, reference was made to the following excerpt from a standard reference book:

D4: B. Schneier, "Applied Cryptography", pp. 30-31, Wiley, 2nd ed., 1995.

It is noted that the label "D4", used to refer to this do cu ment, was not used in the decision but has been in tro duced by the board.

II. A notice of appeal against this decision was received on 25 March 2009, the appeal fee being paid on the same day. A statement of grounds of appeal was received on 27 May 2009. The appellant requested that the decision be set aside and that a patent be granted based on a main or one of two auxiliary requests filed with the grounds of appeal. It also criticized as an abuse of pro cedure that the examining division had only intro duced D4 during the oral proceedings and without any fore warning.

III. In an annex to a summons to oral proceedings the board raised objections under Articles 84 EPC 1973 and 123 (2) EPC against all requests and under Article 56 EPC 1973 against the main request.

IV. In response to the summons, on 12 April 2013, the appellant filed an amended set of claims to replace all three previously pen ding sets of claims and a new de scription page 4 and re ques ted the grant of a patent based on the following docu ments.

claims, no.

1-19 received on 12 April 2013

description, pages

2, 3, 5-38, 40-47 as published

1, 4a, 39 received on 4 July 2007

4 received on 12 April 2013

drawings, sheets

1/22-22/22 as published

At the same time, the appellant informed the board of its intention not to appear at the oral pro ceedings.

V. Claim 1 reads as follows.

"A method of identifying transmissions of digital works to detect unauthorized transmissions of the digital works, the method comprising:

maintaining (702) a registry (244) of information identifying registered works including at least one content based fingerprint for each of the registered works, wherein each of the at least one content based fingerprints has a corresponding feature sequence;

monitoring (706) a network for transmission of at least one packet-based digital signal, wherein the transmission comprises a source IP (internet protocol) address, a recipient IP address, and a digital work;

extracting a plurality of features from the at least one packet-based digital signal, wherein the at least one packet-based digital signal comprises audio data, and wherein each feature is a plurality of characteristics of the at least one packet-based digital signal;

generating (732) a content based fingerprint for the at least one packet-based digital signal from the plurality of features, wherein the content based fingerprint of the at least one packet-based digital signal has a corresponding feature sequence;

performing a probabilistic identification comparison between the feature sequence of the content based fingerprint of the at least one packet-based digital signal and the feature sequence of a content based fingerprint of one of the registered works to determine a probability that the digital work in the transmission of the [at] least one packet-based digital signal is a match to one of the registered works;

determining whether the transmission is an authorized transmission, based on at least one of the source IP address or the recipient IP address, if the transmission of the at least one packet-based digital signal includes at least one portion of one of the registered digital works; and

taking action (720, 722, 726) based on the determination."

Claim 11 sets out a "digital works identification system" which is defined in terms which closely correspond to the wording of claim 1.

VI. The oral proceedings were held on 18 April 2013 as sche duled in the ab sence of the appellant. At the end of the oral pro cee dings, the chairman announced the board's decision.

Reasons for the Decision

The introduction of D4 during the oral proceedings - no deficiency in the first instance proceedings (Art. 11 RPBA)

1. The appellant considers it an "abuse of procedure by the examining division" to have only introduced D4 during the oral proceedings and without any forewarning (see grounds of appeal, point 16). The board notes that the examining division did not introduce D4 to support a new argument but merely to support an allegation about common knowledge in the art that had been made before (see de cision under appeal, reasons 4.6, and mi nutes of oral proceedings, points 40-51). D4 is also rather short and of no par ti cu lar technical com ple xi ty and the board has no rea son to suspect that the re pre sen tative was given insuffi cient time to consider D4 and the exa mi ning di vi sion's related argument. This was also not argued by the appellant in the grounds of appeal nor in response to the summons to oral proceedings, in which the above had been presented as the board's preliminary opinion. The board therefore concludes that no deficiencies were apparent in the first instance proceedings.

The late filed request

2. According to Article 13 (1) RPBA, the board has dis cre tion not to admit amendments to a party's case after it has filed its grounds of appeal. The discretion shall be exercised in view of the new subject-matter sub mitted, the current state of the proceedings and the need for procedural economy. In the present case, the amendments were filed late on Friday, 12 April 2013, and were received by the board only on Monday, 15 April 2013, i.e. a mere three days before the oral pro cee dings. How ever, since the amend ments directly and success fully addressed all the board's concerns raised in the summons to oral pro cee dings and did not intro duce any complication that the board was not able to deal with during oral proceedings and in the appellant's absence, the board exercises its dis cretion to admit the new request.

The invention

3. The application generally relates to the problem of de tec ting and acting upon unauthorized transmission of di gi tal works over the Internet (see page 1, lines 11-14).

3.1 The application proposes to register protected digital works together with so-called "content-based fin ger prints" which are obtained from the digital works by ex tracting a plurality of features from them.

3.2 Then network traffic is monitored. From each inter cep ted digital data packet a content-based fingerprint is generated and compared with the registered finger prints so as to determine "a probability that the un known con tent con tains a registered copyrighted work" (see page 21, lines 22-28).

3.3 In case of a match indicating that the data packet con tains a portion of a registered work a follow-up check is performed to establish whether the copyright owner may have authorized the transmission. The determina tion of whether the transmission is au thorized is based on the source IP address or the reci pient IP address (see page 8, lines 20-23; and page 26, lines 25-31).

3.4 Based on the result of this determination, especially if negative, appropriate "action" is taken such as re cording, reporting or blocking transmission (see page 13, lines 24-31, and page 19, lines 28-31).

3.5 The application is particularly concerned with digital works comprising audio data such as music or video, and a method called the Sto chas tic Audio Matching Mechanism, abbre viated to SAMM, is discussed in detail (cf. page 17, line 8-12 and page 29, line 16 - page 47, line 20). However the description is explicit about the fact that digital works can be of any type, including text, soft ware or other digital content (cf. page 4, line 10; page 12, lines 8-10; page 16, line 27 - page 17, line 14). Depen ding on the type of work, different finger printing methods have to be used which the description refers to as known in the art (see page 17, lines 8-10).

Article 123 (2) EPC

4. Claims 1 and 11 refer to "probabilistic identification comparison" between the fingerprints of the current di gital signal and of one of the registered works "to deter mine a probability that the digital work in the trans mission ... is a match to one of the registered works".

4.1 The board notes that the description discloses the term "probabilistic identification" literally only in the con text of audio data with reference to the SAMM (see page 29, lines 19 and 27).

4.2 Claims 1 and 11 specify that the digital signal "com prises audio data", implying that the digital signal may also comprise other data (for instance, metadata such as the file name and the source and recipient IP addresses). They further specify that the "probabilis tic iden ti fi ca tion comparison" is based on features ex trac ted "from the ... digital signal". This does not imply however that the probabilistic identification is based solely on fea tures extracted from the audio sig nal and cannot, there fore, be supported by SAMM alone.

4.3 The description however specifies that several "assess ment criteria", inter alia based on the content-based fingerprint, "provides only a probability that the un known content contains a registered copyright work". In the board's view, this provides original disclosure for the term "probabilistic identification comparison" in claims 1 and 11, Article 123 (2) EPC.

4.4 That said, the board considers that the skilled person would, in the given context, interpret the term "proba bi listic identification" broadly to mean matching based on de grees of similarity and sui table thresholding - as opposed to binary matching which may only succeed or fail - but would not take it to imply that that si mi la ri ty is based on a rigorous mathematical analysis of pro babilities of identity.

5. The board also notes that the fact that a "feature is a collection of characteristics" is, literally, only dis closed in the context of SAMM (see page 30, lines 19-20). It is disclosed that a temporal sampling of an audio sig nal produces a "single feature" at each "single point in time" which consists of a "collection of the re presentative characteristics".

5.1 The board considers that the terms "features" and "cha racte ris tics" are technically equivalent in the given context. More over the term "feature", albeit wide ly used in the given context, is so broad that it is im possible in ge ne ral to distinguish whether a piece of information con sti tutes a (single) "feature" or a "plu rality of characte ris tics".

5.2 For digital works of arbitrary type the description dis closes that "one or many of various features" may be extracted and that "features [are] obtained from a sampled work" (see page 26, lines 18-20, and page 28, lines 26-27). In view of the foregoing, the board is sa tisfied that the description as originally filed discloses the claimed wor ding of a "feature [being] a plurality of characte ris tics", Article 123 (2) EPC.

6. The description discloses that the monitored data trans mission comprises a source IP address and a reci pient IP address (see page 8, lines 16-23; page 18, lines 11-19 and fig. 2). It also discloses the deter mi nation of whether a transmission is authorized based on the "source add ress" or the "re cipient"/"destination address" (see e.g. ori ginal claims 4, 6, 32 and 34) and that these are com prised in the "packet-based digital signal". In com bi na tion, the board considers that the skilled person would take this to teach, directly and unam biguously, the determination of whether a trans mission is autho rized "based on the source IP address or the recipient IP address", Article 123 (2) EPC.

7. In the decision under appeal the examining division found the then main and first auxiliary requests not to comply with Article 123 (2) EPC, based on the claimed terms "identifiers of registered work" (and its diffe rence, if any, from the term "fingerprint"), the notion of "unique" identification and the claimed fea ture that "unidentified di gital work" be mo ni tored (rea sons 1.1-1.3). Since the amen ded claims do not re fer to "identi fi ers", "unique" identi fi cation or "un i dentified" di gi tal works any more, these objections, as the board un derstands them, need not be gone into further for the purposes of this decision.

8. In summary, the board is satisfied that the amended claims remain within the disclosure of the original appli cation documents and are thus in conformance with Article 123 (2) EPC.

Article 84 EPC 1973

9. Since the amended claims do not refer to "monitoring ... unidentified digital works" any more, the objection un der Article 84 EPC 1973 against this term in the de ci sion (reasons 2), need not be gone into further either. The board has no occa sion to raise any clarity objec tion of its own.

The prior art

10. D2 discloses a steganographic system used, inter ali a, for the automatic detection of unauthorized trans mission of copyrighted digital works (see abstract and page 48, lines 16-19), including audio (see e.g. page 4, lines 27-30). More spe ci fically, D2 defines a library of so-called universal codes (see page 28, line 17 ff.) which may be embedded into a digital work - invisibly, but in a way that allows their retrie val by suitable re cognition software (page 30, lines 21-22) - so as to link the work with its pertinent copy right ow ner (see page 30, line 38 - page 31, line 8).

10.1 D2 discloses an "Internet tollgate" which would "check in co ming video" for the company's "in ternal signature codes" and certain header informa tion and which would not pass any non-authorized mate ri al based on this check (see page 49, lines 7-12). Header information may be information "about the file as a whole" and include information about the author or copy right holder of the data (see page 46, lines 16-20). As an al ter na tive, D2 also dis clo ses "another piece of [the] ... net work" which "per forms mun dane routine moni to ring on In ternet channels to look for unauthorized transmission of ... pro prie tary crea tive property" (see page 49, lines 12-14).

10.2 D2 addresses the problem that "pirates" might modify a pro tec ted digital work so that the embedded codes can no lon ger be recognized (see page 49, lines 16-20) and dis closes that this may be acceptable in some situa tions but not in others. It may be acceptable for the "en ablement of authorized action based on the fin ding of the codes" - because, as the board reads it, a mo di fied digital work will fail to enable the unautho rized ac tion - but may be inacceptable "in the case of 'ran dom moni toring ... for the presence of codes.'" (see page 49, lines 21-24) - because the illicit use of modified works will simply be missed.

11. D4 discloses, in the context of cryptography, that "ha shing" was well-known in the art at least by 1996 as a way of "finger prin ting" files (see sec. 2.4). Hashing is however not suitable for probabilistic iden ti fi ca tion or the detection of unauthorized trans mission of digital works as is now claimed. A method suitable for detecting copyright infringement must be robust against "evasion techniques such as adding a small segment to the beginning of an audio file" (see description, page 3, lines 24-27). This robustness is pro vided by "proba bi listic identi fi ca tion". Hash values however map diffe rent input values to different hash values, how ever small the difference in the input is. This is use ful for an electronic sig na ture, which is meant to be come invalid as soon as the signed document is only slightly manipulated, but not suitable for the claimed purpose of the claims. The board concludes that D4 is no longer relevant to the amended claims.

Article 56 EPC 1973

12. The decision under appeal starts its inventive step assess ment from D2. The board agrees with this choice.

12.1 Claims 1 and 11 differ from D2 in two main respects:

a) Identification of digital works according to the claims is based on probabilistic identification of content-based fingerprints rather than on the de tec tion of water mar ks as used in D2.

b) The claims specify that an unauthorized transmission is determined based on the source or recipient IP address in addition to the fingerprint matching, whereas D2 discloses that digital data is validated based on watermark detection in combination with the verification of header data, which may include the author and the copyright owner of the digital work.

13. Regarding feature "a", as the board understands the de cision under appeal, it argues (reasons 4.5) that the "mundane rou tine monitoring" according to D2 (see page 49, lines 12-14) suggests, if not implies, "well-known monitoring methods" other than watermarking.

13.1 In the board's understanding however (see point 10.1 above), D2 teaches "mundane routine monitoring" as a different way of employing the watermark-based iden tification me thod for transmission control which does not imply or suggest a different identification method (such as fingerprinting) altogether. At the same time, the board disagrees with the appellant that D2 teaches away from using a different identifi ca tion me thod, such as fingerprinting in place of wa termarking. Ra ther, the board is of the opinion that the skilled per son would always assess possible im prove ments of a given method or device.

13.2 The board considers that water mar king and fin ger prin ting are well-known ways of iden ti fying a di gi tal ob ject with well-known res pective advan tages and dis ad vantages. Watermarking operates by incorporating "wa ter marks" into a digital object which can be auto ma ti cally retrieved la ter on. Fin gerprinting in con trast does not incorporate anything in to the digital object but derives an identi fi er from the given content. The processing requirements for wa ter marking are typically smaller than those for fin ger printing, but watermarking cannot protect already released digital works and can be removed or disabled, leaving a digital work un protected (see description, page 3, lines 8-12).

13.3 In the board's judgment therefore it would have been ob vious for the skilled person seeking to improve the dis closure of D2 to consider fingerprin ting as an al ter native to watermarking to identify digital do cu ments. Once this choice is made, the board further con siders that the claimed use of fingerprints follows ob vi ously, in particular the use of a registry, the cal culation of a fingerprint from a digital signal in trans mission and its comparison with the registered fin ger prints. Even the claimed "probabilistic identi fi cation" is, in the broad interpretation given above (see point 4.4), con si dered to be a commonly known way of ro bust finger prin ting.

13.4 The board thus concludes that difference "a" is in sufficient to establish an inventive step over D2.

14. Regarding feature "b", with reference to the IP add resses, the detection of unauthorized transmission as claimed is based on properties of the network or, more specifically, of the in di vidual network components involved in a trans mission. In contrast, D2 only discloses the use of meta data of the digital work itself (header information) and of individuals involved (author, copyright owner).

14.1 Difference "b" thus contributes to making the detection mechanism of D2 more network aware. As part of a net work monitoring mechanism as claimed the board finds that this contribution makes a technical contribution to the art.

14.2 The board further considers that the evaluation of IP addresses is not suggested by the use of header information according to D2 nor by any of the other documents on file.

14.3 Therefore, by virtue of difference "b", the board comes to the conclusion that the claimed matter is based on an inventive step over D2 and the available prior art, Article 56 EPC 1973.

ORDER

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the examining division with the order to grant a European patent with the following documents:

claims, no.

1-19 received on 12 April 2013

description, pages

2, 3, 5-38, 40-47 as published

1, 4a, 39 received on 4 July 2007

4 received on 12 April 2013

drawings, sheets

1/22-22/22 as published