Method And An Apparatus For Securely Signing Application Data

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.