摘要:
A method of encrypting data using a first key and multiple encryption keys at least in part based on the first key. The method includes encoding the data into a redundant representation by distributing the information content of the data among a number of groups, each group being associated with a respective encryption key of the multiple encryption keys, each encryption key being associated with at least one group, the redundant representation allowing recovery of the data in the absence of the groups associated with the at least one of the multiple encryption keys, and encrypting each group by the respective associated encryption key.
摘要:
The present invention relates to a method and apparatus for encrypting data (105) by means of a first key (115), and a method and apparatus for decrypting encrypted data by means of a second key (185). The present invention alleviates the need for exact key information by allowing encryption of data (105) by means of a first key (115) and subsequent decryption of the encrypted data by means of a second key (185) without the need for the first key (115), provided that the first key (115) and the second key (185) form a sufficient estimate of an encryption/decryption key pair. During encryption, multiple encryption keys (135), at least in part based on the first key (115), are used to encrypt a redundant representation (122) of the data (105). The encrypted data (124) may subsequently be decrypted by using multiple decryption keys (165) based on the second key (185), without the need for the first key (115), provided that the second key (185) forms a sufficient estimate of the first key (115).
摘要:
Client terminals report an easy-to-calculate identifier such as the Internet URL or a cryptographic hash of the content to a server. The server collects and counts the reported identifiers so as to obtain preliminary statistics. By aggregating these reported identifiers into the preliminary statistics, identifiers are revealed that are likely popular content. The server selects one or more identifiers from the preliminary statistics and makes these available to at least a subset of clients. The clients that obtain these one or more identifiers then access content and compute the easy-to-calculate identifiers as usual. If the computed identifier matches one of the identifiers obtained from the server, the client will additionally extract a watermarked identifier or compute a digital fingerprint of the content in question and report this to the server. The server then uses the received identifier or fingerprint to create final statistics by aggregating the preliminary statistics.
摘要:
The invention relates to embedding a spread spectrum watermark in a data signal as well as to detection of the embedded watermark. A data signal (4) is encrypted (15) or received in the form of an encrypted data signal (9), the signal being encrypted by modifying (3) it in accordance with one or more entries of a look-up-table (2) in which an encryption table (6) is stored. The encryption is carried out by a first computing device (15) such as a server device. The watermark is actually embedded while decrypting (13) the signal. This takes place in a second computing device (16), possibly in a client device, in a similar manner The client device employs a decryption table (8), which is a modified (i.e. watermarked) version of the encryption table (6). The decryption table may generated by the server and securely communicated to the client. The data signal is decrypted in accordance with entries of a look-up-table (12). The look-up-tables (2,12) in server and client are addressed by the same sequence of pointers generated by respective index generators (1). The mismatch between encryption table (6) and decryption table (8) causes the de-signal (14) to have an embedded watermark.
摘要:
A system and a method for secure remote informed watermark detection making use of a side-information. The system in overview comprises a remote detector and a server computing system wherein a database with side-information assigned to specific descriptors of data signals is stored at the server computing system and wherein a remote detector intending to identify the watermark of a data signal will derive the descriptor of the data signal and subsequently contact the trusted server computing system in order to obtain the necessary side-information for the informed watermark detection.
摘要:
Disclosed are a method and a system for secure watermark embedding in a server-client configuration (60,70). The method comprises encrypting (210) the data signal (x) and generating (240) a decryption key wherein a watermark (Wi) is included. The client decrypts (420) the encrypted data signal in order to obtain a watermarked data signal (xw). In accordance with the invention, the encryption mechanism and decryption key are made dependent on a perceptual mask (m1,m2) so as eventually make the embedded watermark more robust.
摘要:
A lossless, reversible data embedding technique uses a generalization of least-significant-bit modification. The portions of the signal that are susceptible to embedding distortion are compressed and sent as part of the embedded payload. A prediction-based conditional entropy coder uses unaltered portions of the host signal to improve lossless data capacity.
摘要:
A device for rendering content from a first source comprising a first input for receiving the content from the first source, a second input for receiving a substitution content item from a second source, a substitution module for substituting a segment of the content with the substitution content item, and rendering means for rendering the content wherein the segment is substituted with the substitution content item. The rendering device has monitoring module for monitoring the reception of the segment, and controlling the substitution module dependent on whether the segment is being received, such that the substitution module ceases the substitution upon failure to receive the segment.
摘要:
A secure forensic watermarking system is disclosed that distributes the same encrypted content to all users. The decryption key is different for each user, so that the decrypted content differs slightly from the original, i.e. is watermarked. Forensic tracking is possible by distributing unique decryption keys to individual users. The invention allows a forensic mark to be securely embedded in the compressed domain signal. In an embodiment of this invention, the content (x) and an encryption sequence (r) are entropy encoded using a homomorphic Huffman table. A homomorphic Huffmann table is a table H having the property that there exists an operation f( ) such that H-1 (f(H(a),H(b)))=a+b.
摘要翻译:公开了一种安全的法医水印系统,其将相同的加密内容分发给所有用户。 解密密钥对于每个用户是不同的,使得解密的内容与原始内容略有不同,即被加密。 通过向个别用户分发唯一的解密密钥可以进行取证跟踪。 本发明允许将法医标记安全地嵌入到压缩域信号中。 在本发明的一个实施例中,内容(x)和加密序列(r)使用同态霍夫曼表进行熵编码。 同形霍夫曼表是具有存在使得H-1(f(H(a),H(b)))= a + b的操作f()的性质的表H。
摘要:
The present invention relates to methods and apparatus for digital content distribution. A method of transferring digital content from a first entity (60) to a second entity (70) includes the steps of: a transfer control entity (50) transmitting a transmission key (KA) to the first entity, the first entity storing content data comprising digital content embedded with a first watermark (WA). The first entity applies the transmission key to the content data to remove the first watermark from the digital content and encrypt the digital content. The first entity transmits the encrypted digital content (CX) to the second entity. The transfer control entity transmits a receive key (KB) to the second entity and the second entity applies the receive key to the encrypted digital content to generate decrypted data comprising the decrypted digital content embedded with a second watermark (WB).