# US 2014/0195811 A1 · Method And An Apparatus For Securely Signing Application Data > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0195811 A1 - Document ID: US20140195811A1 - Status: Published application - Kind: A1 - Application number: 14/143,083 - Filed: 2013-12-30 - Published: 2014-07-10 - Earliest claimed: 2012-12-31 - Assignees: Vasco Data Security, Inc. - Inventors: Harm Braams - Web page: https://patentgrep.com/patent/US20140195811A1 ## CPC - H04L 9/3247: {involving digital signatures} - G06F 21/34: involving the use of external additional devices, e.g. dongles or smart cards - G06F 21/64: Protecting data integrity, e.g. using checksums, certificates or signatures - G06F 2221/2153: Using hardware token as a secondary aspect - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract The invention provides a method and apparatus for the secure electronic signing of electronic documents and data. In a preferred embodiment, a method for generating a first digital signature associated with a set of application data is disclosed. The method comprises the steps of: obtaining a first digital representation in a high level first data format of the set of application data; generating a second digital representation in a low level second data format of the application data whereby said low level second data format is different from said high level first data format; presenting an analog representation of the set of application data to a user, whereby said second digital representation is a precise and accurate representation of said analog representation; obtaining an indication whether said user approves said analog representation for signing; if said indication indicates that the user approves said analog representation for signing, generating said first digital signature over said second digital representation using a first signature key associated with the user. ## Claims ### Claim 1 An apparatus for digitally signing data comprising: a first data communication interface adapted to connect the apparatus to a host computing device and to exchange data with the host computing device; a first human output interface adapted to present data to a user of the apparatus; and a first human input interface adapted to receive inputs from said user; whereby the apparatus is adapted to: obtain a first digital representation of data to be signed, said first digital representation being in a high level first digital data format; generate a second digital representation of the data to be signed, said second digital representation being in a low level second digital data format that is different from said high level first digital data format; present an analog representation of the data to be signed to the user by means of said first human output interface, whereby said second digital representation is a precise and accurate digital representation of said analog representation presented by said first human output interface to the user; receive from the user by means of said first human input interface an indication whether the user approves or rejects said analog representation of the data to be signed; and, if said indication indicates that the user has approved the analog representation of the data to be signed as presented by the first human output interface: generate a first digital signature over said second digital representation of the data to be signed using a first digital signature algorithm parameterized by a first secret signature key associated with the user, and return the generated signature to the host computing device. ### Claim 2 (depends on 1) The apparatus of claim 1 further adapted to generate said second digital representation of the data to be signed by converting the data to be signed from said first digital representation to said second digital representation. ### Claim 3 (depends on 1) The apparatus of claim 1 further adapted to receive said first digital representation of the data to be signed from said host computing device. ### Claim 4 (depends on 1) The apparatus of claim 1 wherein said host computing device comprises a local computing device used by the user to interact with an application, and wherein said apparatus is locally connected to said local computing device by means of said first data communication interface and wherein the apparatus receives said first digital representation of the data to be signed from said local computing device over said first data communication interface. ### Claim 5 (depends on 4) The apparatus of claim 4 wherein said first data communication interface comprises a USB interface. ### Claim 6 (depends on 4) The apparatus of claim 4 wherein said first data communication interface comprises a Bluetooth interface. ### Claim 7 (depends on 1) The apparatus of claim 1 further comprising a second data communication interface for accepting a removable secure key storage device and for exchanging commands and responses with said secure key storage device, whereby the secure key storage device stores said first secret signature key and whereby generating said first digital signature comprises: the apparatus sending data related to said second digital representation of the data to be signed to the secure key storage device, the secure key storage device performing cryptographic calculations with said secret signature key over said data related to said second digital representation of the data to be signed, and the apparatus receiving from the secure key storage device the result of said cryptographic calculations. ### Claim 8 (depends on 7) The apparatus of claim 7 wherein said data related to said second digital representation of the data to be signed comprise second digital representation of the data to be signed. ### Claim 9 (depends on 7) The apparatus of claim 7 wherein the apparatus is further adapted to generate a digital message digest over said second digital representation of the data to be signed, and wherein said data related to said second digital representation of the data to be signed comprise said digital message digest. ### Claim 10 (depends on 7) The apparatus of claim 7 wherein said second data communication interface comprises a smart card interface and said secure key storage device comprises a smart card. ### Claim 11 (depends on 7) The apparatus of claim 7 wherein the apparatus is further adapted to store a second signature key associated with the apparatus, to generate a second digital signature using said second signature key, and to return said second digital signature to the host computing device. ### Claim 12 (depends on 11) The apparatus of claim 11 further adapted to generate said second digital signature over said second digital representation of the data to be signed. ### Claim 13 (depends on 11) The apparatus of claim 11 further adapted to generate said second digital signature over said first digital signature. ### Claim 14 (depends on 11) The apparatus of claim 11 further adapted to obtain a time stamp and to include said time stamp in the data over which said second digital signature is made. ### Claim 15 (depends on 11) The apparatus of claim 11 further adapted to obtain a location stamp and to include said location stamp in the data over which said second digital signature is made. ### Claim 16 (depends on 1) The apparatus of claim 1 wherein said human output interface comprises a display and said second digital representation comprises a representation of the actual image displayed to the user by said display. ### Claim 17 (depends on 16) The apparatus of claim 16 wherein said representation of said image is in a data format that defines the size of the image in pixels and that defines the color for each pixel of the image. ### Claim 18 (depends on 17) The apparatus of claim 17 wherein the representation of said image comprises a bitmap. ### Claim 19 (depends on 17) The apparatus of claim 17 wherein the representation of said image is in a data format using data compression. ### Claim 20 (depends on 19) The apparatus of claim 19 wherein the representation of said image is in a data format using lossless data compression. ### Claim 21 (depends on 1) The apparatus of claim 1 wherein said first digital signature algorithm comprises an asymmetric digital signature algorithm and wherein said first secret signature key comprises a private key of a public-private key pair. ### Claim 22 (depends on 1) The apparatus of claim 1 further adapted to return to said host computing device said second digital representation of the data to be signed. ### Claim 23 (depends on 1) The apparatus of claim 1 further adapted to return to said host computing device one or more parameters of said second digital representation of the data to be signed or of a conversion process to generate said second digital representation from said first digital representation. ### Claim 24 (depends on 23) The apparatus of claim 23 wherein said one or more parameters together with said first digital representation of the data to be signed unambiguously determine the precise digital contents of said second digital representation of the data to be signed. ### Claim 25 (depends on 23) The apparatus of claim 23 wherein said one or more parameters define characteristics of said human output interface. ### Claim 26 (depends on 23) The apparatus of claim 23 wherein said human output interface comprises a display and said second digital representation comprises a representation of the actual image displayed to the user by said display and wherein said one or more parameters comprise the dimensions in pixels and the color resolution of said representation of said image. ### Claim 27 (depends on 23) The apparatus of claim 23 wherein said data to be signed comprise text and wherein said human output interface comprises a display and said second digital representation comprises a representation of the actual image displayed to the user by said display and wherein said one or more parameters comprise information about fonts that are used to translate references to characters in said first digital representation into sets of pixels that are a part of said image displayed to the user. ### Claim 28 (depends on 1) The apparatus of claim 1 wherein the host computing device comprises a remote server hosting a remotely accessible application and whereby the apparatus further comprises a general purpose computing device that is adapted to communicate with said remote server over a public data communications network and that comprises a second human input interface and a second human output interface for enabling the user to interact with said remotely accessible application. ### Claim 29 (depends on 28) The apparatus of claim 28 having a software architecture comprising at least a first layer and a second layer whereby the first layer comprises a first set of software components which can be autonomously be added, removed, replaced or upgraded by the user, and the second layer consists of a second set of hardware and software components whereby the addition, removal, replacement or upgrade of the software components of said second set is subject to a stringent software verification and upgrade mechanism which is not under the sole control of the user and which is at least partly under control of a trusted third party; whereby said first set of software components comprises components for converting said first digital representation of the data to be signed into an intermediate representation of the data to be signed, and whereby said second set of components comprises components for converting said intermediate representation into said second digital representation and causing said intermediate representation to be represented to the user as said analog representation output by said first human output interface and obtaining from said second human input interface or said first human input interface an indication whether the user approves said analog representation for signing, and components for said generating of said first digital signature over said second digital representation of the data to be signed if said indication indicates that the user approves the analog representation for signing. ### Claim 30 (depends on 29) The apparatus of claim 29 wherein said second set of components further comprises a secure signing mode indicator component and said second human output interface comprises said first human output interface; and wherein said apparatus has a secure signing mode of operation whereby, if the apparatus is in said secure signing mode: the secure signing mode indicator component gives an indication to the user that the apparatus is in secure signing mode; and the output of said first human output interface is exclusively determined by components of the second layer; and said indication that the user approves the analog representation for signing requires physical action of the user and cannot be emulated by a component of the first layer. ### Claim 31 (depends on 30) The apparatus of claim 30 whereby said second set of components further comprises a secure signing mode proof component for generating a cryptographic proof that said first digital signature has been generated in secure signing mode. ### Claim 32 (depends on 31) The apparatus of claim 31 whereby access to said secure signing mode proof component is reserved to components of said second set of components. ### Claim 33 (depends on 31) The apparatus of claim 31 wherein the apparatus is further adapted to generate said cryptographic proof only when the apparatus is in said secure signing mode. ### Claim 34 (depends on 31) The apparatus of claim 31 whereby said secure signing mode proof component is adapted to store a second signature key associated with the apparatus and to generate a second digital signature using said second signature key. ### Claim 35 (depends on 34) The apparatus of claim 34 further adapted to generate said second digital signature over said first digital signature. ### Claim 36 (depends on 34) The apparatus of claim 34 further adapted to generate said second digital signature over said second digital representation of the data to be signed. ### Claim 37 (depends on 30) The apparatus of claim 30 whereby said secure signing mode indicator component gives said indication to the user that the apparatus is in secure signing mode only if the apparatus is in said secure signing mode. ### Claim 38 A method for generating a first digital signature associated with a set of application data, the method comprising the steps of: obtaining a first digital representation in a high level first data format of the set of application data; generating a second digital representation in a low level second data format of the application data whereby said low level second data format is different from said high level first data format; presenting an analog representation of the set of application data to a user, whereby said second digital representation is a precise and accurate representation of said analog representation; obtaining an indication whether said user approves said analog representation for signing; if said indication indicates that the user approves said analog representation for signing, generating said first digital signature over said second digital representation using a first signature key associated with the user. ### Claim 39 (depends on 1, 38) The method of claim 38 wherein the steps of presenting said analog representation to the user, obtaining said indication whether said user approved the analog representation for signing and generating said first digital signature are performed using the apparatus of claim 1; the method further comprising the steps of: generating by said apparatus a second digital signature over said first digital signature using a second signature key associated with the apparatus, said second digital signature indicating that said steps of presenting said analog representation to the user, obtaining said indication whether said user approved the analog representation for signing and generating said first digital signature have been performed using said apparatus. ### Claim 40 (depends on 38) The method of claim 38 wherein said analog representation comprises an image displayed by the display of a computing device; and said second digital representation comprises a bitmap of said analog representation. ### Claim 41 (depends on 41) The method of claim 41 wherein said first digital representation comprises an electronic text document in a high level text processing format. ### Claim 42 (depends on 38) A method for verifying a first digital signature associated with a first digital representation in a high level first data format of a set of application data, whereby said first digital signature has been generated with the method of claim 38, the method comprising: obtaining the second digital representation over which the first digital signature was generated; cryptographically verifying the correctness of the first digital signature over said second digital representation; extracting from said first digital representation a first set of reference data in a third data format; extracting from said second digital representation a second set of reference data in a fourth data format; and comparing said first set of reference data with said second set of reference data. ### Claim 43 (depends on 42) The method of claim 42 wherein said second digital representation comprises a bitmap; said first set of reference data comprises a first text and said third data format comprises a first text format; and said second set of reference data comprises a second text and said fourth data format comprises a second text format. ### Claim 44 (depends on 1) A system for generating a digital signature associated with a set of application data, the system comprising: a remote application server for handling the application data; a general purpose computing device for allowing a user to interact with said remote application server; and a secure signing device comprising the apparatus of claim 1 for generating a first digital signature over the application data and connected to said general purpose computing device. ### Claim 45 (depends on 42, 44) The system of claim 44 further comprising a signature verification component for verifying said first digital signature using the method of claim 42. ### Claim 46 (depends on 44) The system of claim 44 wherein the general computing device comprises the secure signing device.