WO1999011020A1 - Masquage de donnees cryptees - Google Patents

Masquage de donnees cryptees Download PDF

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Publication number
WO1999011020A1
WO1999011020A1 PCT/US1998/017321 US9817321W WO9911020A1 WO 1999011020 A1 WO1999011020 A1 WO 1999011020A1 US 9817321 W US9817321 W US 9817321W WO 9911020 A1 WO9911020 A1 WO 9911020A1
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WO
WIPO (PCT)
Prior art keywords
message
carrier signal
encrypted message
sequence
encryption
Prior art date
Application number
PCT/US1998/017321
Other languages
English (en)
Inventor
Jordan J. Glogau
Edward J. Delp, Iii
Raymond B. Wolfgang
Eugene Ted Lin
Original Assignee
Purdue Research Foundation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Purdue Research Foundation filed Critical Purdue Research Foundation
Priority to US09/485,759 priority Critical patent/US6912658B1/en
Publication of WO1999011020A1 publication Critical patent/WO1999011020A1/fr

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T1/00—General purpose image data processing
    • G06T1/0021—Image watermarking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/06—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
    • H04L9/065—Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
    • H04L9/0656—Pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam's cipher
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
    • H04L9/0819—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s)
    • H04L9/083—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32154—Transform domain methods
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32203—Spatial or amplitude domain methods
    • H04N1/32208—Spatial or amplitude domain methods involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition
    • H04N1/32213—Modulating the least significant bits of pixels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32309—Methods relating to embedding, encoding, decoding, detection or retrieval operations in colour image data
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2201/00—General purpose image data processing
    • G06T2201/005—Image watermarking
    • G06T2201/0051—Embedding of the watermark in the spatial domain
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2201/00—General purpose image data processing
    • G06T2201/005—Image watermarking
    • G06T2201/0081—Image watermarking whereby both original and watermarked images are required at decoder, e.g. destination-based, non-blind, non-oblivious
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2209/00—Additional information or applications relating to cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
    • H04L2209/16—Obfuscation or hiding, e.g. involving white box
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3261—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of multimedia information, e.g. a sound signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3269—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of machine readable codes or marks, e.g. bar codes or glyphs
    • H04N2201/327—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of machine readable codes or marks, e.g. bar codes or glyphs which are undetectable to the naked eye, e.g. embedded codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/328—Processing of the additional information
    • H04N2201/3281—Encryption; Ciphering

Definitions

  • the present invention relates to methods and apparatus for hiding data within a digital signal, and particularly for concealing information within multimedia signals such as digital image, audio, or video signals. More particularly, the present invention relates to methods and apparatus for embedding and retrieving information into and out of a digital signal used in multimedia applications while minimizing the effect on the multimedia application of the digital signal.
  • a method of hiding data is provided.
  • a message to be hidden and an encrypting sequence are provided along with a carrier signal that conveys information (unrelated to the message).
  • An encrypted message is generated based on the message and the encrypting sequence.
  • the encrypted message is embedded into the carrier signal by performing an exclusive-OR of the encrypted message with a first portion of the carrier signal.
  • the carrier signal is a digital image
  • the first portion of the carrier signal is an LSB plane of the digital image.
  • the digital image has a plurality of color planes
  • the first portion of the carrier signal is an LSB plane of a first color plane
  • the second portion of the carrier signal is an LSB plane of a second color plane.
  • the carrier signal is transmitted to a receiving location.
  • the encrypted message is extracted and from the carrier signal and deciphered at the receiving location.
  • the encrypted sequence is generated based on an encrypting key.
  • the encrypted message is generated by performing an exclusive-OR of the message with the encrypting sequence.
  • a method of data hiding in which an encryption key and a carrier signal that conveys information unrelated to the encryption key are supplied. An encryption sequence based on the encryption key is generated. The encryption sequence is embedded into the carrier signal.
  • the encryption key is a public key for an asymmetric encryption algorithm.
  • the carrier signal can be a signal such as a digital image, digital audio, or digital video.
  • the encryption sequence is substantially random, and can be generated based on a linear feedback shift register.
  • the encryption sequence is embedded into the carrier signal by performing an exclusive-OR of the encryption sequence with a portion of the carrier signal.
  • the carrier signal including the embedded encryption sequence is transmitted to a receiving location.
  • the encryption sequence is extracted from the composite signal at the receiving location.
  • the encryption sequence is decrypted to obtain the encryption key.
  • the encryption key is used to generate an encrypted message at the receiving location, and the encrypted message is transmitted from the receiving location.
  • a method of data hiding is provided.
  • An encrypted message is embedded into a first portion of a carrier signal and message extraction information is embedded into a second portion of the carrier signal for extracting the encrypted message from the first portion of the carrier signal.
  • the encrypted message is embedded by performing an exclusive-OR of the encrypted message with the first portion of the carrier signal.
  • the message extraction information is embedded by performing an exclusive-OR of the first portion of the carrier signal with the second portion of the carrier signal.
  • the first and second portions of the carrier signal can be first and second bit-planes of a digital image.
  • a method of exchanging data hidden in a carrier signal is provided.
  • a signal including hidden data is generated by transforming a carrier signal from a first domain into a second domain.
  • a message is embedded into the carrier signal in the second domain.
  • the carrier signal is transformed back from the second domain to the first domain.
  • the signal including hidden data is sent to a receiving location.
  • the message is obtained from the signal including hidden data at the receiving location by transforming the signal including hidden data into the second domain and extracting the message.
  • the message is encrypted prior to generating the signal including hidden data.
  • the message is decrypted after obtaining the message from the signal including hidden data.
  • a data hiding apparatus generates an encryption sequence based on an encrypting key.
  • An encrypted message generator generates an encrypted message based on the encryption sequence and an input message.
  • An encrypted message embedder embeds the encrypted message into a carrier signal.
  • the encryption sequence generator generates a substantially random encryption sequence.
  • the encrypted message embedder performs an exclusive-OR of the encrypted message with a portion of the carrier signal.
  • the encrypted message embedder replaces a first LSB plane of a digital image with information based on a second LSB plane of the digital image and performs an exclusive- OR of the encrypted message with the second LSB plane of the digital image.
  • the encrypted message generator performs an exclusive-OR of the input message with the encrypting sequence to generate the encrypted message.
  • Fig. 1 is a block diagram of two computer systems connected over a network, each computer system configured with a processor and memory for implementing embodiments of the present invention
  • Fig. 2 is a flow chart showing a method according to the present invention for hiding data within an image for transmission over a network
  • Fig. 3 is a high level block diagram showing a technique for embedding encrypted information into a carrier signal
  • Fig. 4 is a more detailed block diagram similar to Fig. 3 showing a similar, more specific technique for embedding encrypted information into a carrier signal;
  • Fig. 5 is a stylized representation of a message format containing embedded, hidden information
  • Fig. 6 is a stylized representation similar to Fig. 5 of an alternative message format; and Fig. 7 is a flow chart showing an alternative method according to the present invention for hiding data within an image for transmission over a network.
  • Computer network 10 illustratively includes computer systems 12, 18 connected through a series of network communication devices
  • a network 22 such as the standard telephone lines, or the Internet or World Wide Web.
  • a network 22 such as the standard telephone lines, or the Internet or World Wide Web.
  • Computer systems 12, 18 are illustratively personal computers and each includes basic elements such as a processor 26, 32, memory 28, 34, storage device 30, 36, and display 31, 38.
  • Computer systems 12, 18 can also include optional peripheral devices such as removable storage device 40 (e.g., a CD-ROM or VA inch disk drive).
  • FIG. 2 An exemplary method of data hiding according to the present invention that is suitable for carrying out on computer network 10 is shown in Fig. 2.
  • an image is used to transport and exchange data that is embedded in the image itself and that cannot be perceived by the human eye.
  • An appropriate analogy is that the image acts as an envelope, with the embedded data transmitted with the image being equivalent to a letter contained within the envelope.
  • Conventional encryption such as PGP or RSA is used to enhance security of the embedded data. The security is improved because the encrypted data is hidden within the image and therefore cannot be recognized as such. This allows for secure data communication and exchange over an insecure transmission channel.
  • step 50 an original digital image is obtained.
  • a secret message that is desired to be embedded into the image is generated in step 52.
  • a message encrypting key is used in step 54 to generate an encryption sequence.
  • the message encrypting key can be a seed value for use in generating an m-sequence from a linear feedback shift register as discussed in more detail below, although it is understood that any suitable message encrypting algorithm can be used.
  • the message encrypting key will ultimately be used by the recipient of the image embedded with the secret message.
  • step 56 the secret message from step 52 is encrypted with the encryption sequence from step 54 to create an encrypted message.
  • the encrypted message is then embedded into the image in step 58. There are many methods to embed the encrypted message into the image such as the method discussed below, but, again, it is understood that other suitable methods can be used.
  • the image with the embedded message is then made available such as on a public network as shown in step 60.
  • the secret message from step 52 is actually information that is not desired to be kept secret, such as a public key for an asymmetric encryption algorithm
  • the encryption key from step 54 is also made available on the public network as shown in steps 62, 64.
  • the message can be a public encryption key that is hidden within the image but that is readily available to a party that has knowledge of the fact that the hidden message exists.
  • This provides a convenient way of exchanging information, such as allowing an individual to make a public encryption key available over the World Wide Web by posting it within an image on a Web site, while still concealing the information from the casual observer. It is useful at this point to provide some preliminary definitions before discussing a specific implementation of the method of Fig. 2.
  • the symbol ⁇ denotes a bit exclusive-OR function (equivalently, modulo-2 addition). Table 1 illustrates the exclusive-OR function:
  • a digital image is typically represented with a two dimensional array of pixel values. If A is the array of pixel values, then A(x,y) denotes the pixel value in the x-th column of the y-th row of the array. Each index x,y begins at zero, and by convention the origin is at the upper-left corner with positive coordinates going rightwards and downwards, although this convention is somewhat arbitrary.
  • the digital image is a 24-bit RGB image with pixel values ordered as shown in Table 2: xx
  • bits 16-23 refer to the red component
  • bits 8-15 refer to the green component
  • bits 0-7 refer to the blue component for any given pixel value.
  • Ioo(x,y) refers to the least-significant bit of the green component of the (x,y)- pixel in the image I. Since bit GO is equivalent to bit 8, is equivalent to I 8 (x,y).
  • this labeling convention is somewhat arbitrary.
  • An m-sequence is a pseudo-random sequence of binary digits (bits). m-sequences have good statistical properties and can be generated by linear feedback shift registers (configured appropriately as is known in the art).
  • Knowing the size (number of bits), structure (the feedback configuration), and initial fill (the initial contents of each bit) of the shift register allows the reconstruction of the entire m-sequence.
  • the m-sequences here illustratively are generated by a 96-bit m-sequence generator. If the structure and size of the shift register are known (as would be the case with this embodiment), and if a consecutive portion of the m-sequence equal to twice the shift register size is also known, the initial fill used to generate the sequence can be determined. In this embodiment the initial fill is used as the key that generates the m-sequence. In this way, the key can be determined from the sequence itself by techniques known to those skilled in cryptography.
  • a sequence function z(i) is defined to provide a one-to-one mapping from i->(x,y), where i is an ordinal number and (x,y) refers to coordinate values in an image.
  • the ordinal i ranges from zero to N-l, where N is the total number of pixels in the image.
  • z(0), z(l), z(2), etc. to obtain a sequence of pixel coordinates (x ls yi), (x 2 ,y 2 ), etc.
  • z(i) (i mod ImageWidth,
  • Input signals are a source image 66 (obtained in step 50), an unencrypted message 68 (generated in step 52), and an encrypting key 70 (used in step 54).
  • Message 68 and encrypting key 70 are processed by an encrypted message generator 76 to create an encrypted message signal 72.
  • Encrypted message 72 is an input along with source image 66 into composite signal generator 78, which creates a composite signal 74 containing source image signal 66 embedded with encrypted message 72.
  • Composite signal generator 78 illustratively embeds encrypted message 72 into the least-significant bit in the green plane IQ O CX ) of source image 66 to create a new least-significant green bit-plane I' G o( ⁇ > y) of composite signal 74.
  • Composite signal generator 78 eliminates the requirement of using original image signal 66 by encoding the original Ioo(x,y) into the least-significant red bit-plane I' R0 (x,y) of composite signal 74 as discussed below.
  • I' is initially set to be an exact copy of I. I' is then traversed in order z(i) and the red and green least-significant bit planes are set to:
  • I' GO (Z )) K PUB (i) ⁇ r ⁇ zO)) ⁇ m-seq(2i+l)
  • K PUB (i) refers to the I-th bit of K PUB
  • m-seq(j) refers to the j-th bit in the m- sequence using K, as the initial fill.
  • the first step is to extract I G0 *(z(i)) by using the least-significant red bit plane and the m-sequence:
  • the method of the invention provides for including within the image both the message that is embedded or encrypted in the image as well as the information needed to extract or decrypt the message from the image.
  • a more specific method corresponding to an implementation of the method of Figs. 2 and 3 is shown Fig. 4.
  • the same input signals are used, that is, source image 66 (I), message 68 (here, Q instead of K PUB ), and encrypting key 70 (K j ) are used.
  • the primary refinement in the method of Fig. 4 as compared with Fig. 3 is an encoding process to handle varying length messages 68.
  • Message 68 which in the example of Fig. 3 was a public encryption key for use in an asymmetric cryptography system, can more generally simply be a collection of bits intended to be encrypted and is referred to here as Q.
  • the length (i.e., the total number of bits) of Q is denoted
  • the i-th bit of the message Q is denoted Q(i), where the bits are numbered from 0 to
  • Message 68 (Q) is an input signal to message generator 82 which has as a second input the output from a random noise generator 84.
  • Random noise generator 84 illustratively is also a 96-bit m-sequence generator using an initial fill of a computer system time value, although other suitable random signal generators can be used.
  • Encrypting key 70 (K,) is an input signal (initial fill) to an m-sequence generator 80 that illustratively is the same as random noise generator 84, which then generates as an output an encrypting sequence 86.
  • the message 88 to be encoded onto image 66 (I) is generated by message generator 82 with special properties and is denoted Q' to show that it is derived from Q.
  • Q' has the following properties. For any given source image I, regardless of what message Q is being encoded, the size of a message Q' is the same as the total number of pixels in image I (that is,
  • # pixels in I).
  • bits of message Q' are labeled according to standard convention, that is, the first bit (or the left-most bit if Q' is viewed as an ordered bit stream from left to right as shown in Fig. 5) is numbered zero. Thus the bits of Q' are numbered from zero to
  • Q' The structure of Q' is shown in Fig. 5. All bits except the last sixty-four form a data area 92.
  • the last sixty-four bits consist of two thirty-two bit words (StartPos and Length, in that order), which form a Trailer.
  • Data area 92 includes data bits 98 that correspond to the message Q itself, and random bits 97, 99 that help hide the location of Q (bits 98) within Q'.
  • message generator 82 computes the length of message Q and stores its value in the final 32 bits 94 of the Trailer. The value of the length is not directly encoded and instead a value congruent (actual length modulo Data Area size) is placed in the 32-bit word. It is trivial to recover the length from this encoded value.
  • Starting position 94 describes the location within data area 92 where the bits of the message Q reside.
  • Message generator 82 randomly chooses a place 98 to store Q and populates all other bits of unused portions 97, 99 in data area 92 with random noise generated by random noise generator 84.
  • Q can be anywhere in data area 92.
  • Including noise for portions 97, 99 of data area 92 unused by message Q improves security of data embedded within I because the noise increases the difficulty of recognizing the existence or location of Q within the data area.
  • the encoding of each bit of message Q' is encoded onto image I on a one- bit per one-pixel basis using an exclusive-OR as discussed above for the method of Fig. 3.
  • the output of m-sequence generator 80 (with K, as a seed value) is used to encrypt Q' in encrypter 90.
  • the encrypted Q' is embedded onto the LSB green plane I ⁇ ,.
  • Encrypted message Q is subsequently extracted from Q' by locating its starting position and length from the trailer. The extracted Q is then decoded as discussed above.
  • Random number generator 84 and m-sequence generator 80 can be different. Even if both use 96-bit m-sequence generators, this can be achieved simply by changing the feedback coefficients.
  • the message length 94 in the trailer can be relocated to data area 92 as shown in Fig. 6. This relocation will limit the ability of an attacker to take advantage of a known size of message Q.
  • step 102 the carrier image is transformed from a first domain to a second domain.
  • a typical RGB image that is considered to be represented in a spatial domain can be transformed using a discrete cosine transform.
  • a message is then embedded into the transformed carrier image in step 104, using any appropriate technique for embedding a message onto a carrier signal.
  • An example of a transformed image into which a message can be embedded would be a JPEG image.
  • the message can also be pre-encrypted before being embedded into the transformed image to further improve security.
  • the image is then transformed back into the first domain in step 106 and made available for access by third parties in step 108. For a third party to extract the message the steps are essentially reversed.
  • the image is copied by the third party in step 110, and it is then transformed into the second domain in step 112 using the same transform performed in step 106.
  • the message is extracted in step 114, again, using any appropriate technique that corresponds to the technique used in step 104 for originally embedding the message. If the message was pre-encrypted then another decryption step (not shown) will be necessary.
  • Encrypted messages relying on the use of encryption keys are used in the methods discussed above. For example, if a pre-encrypted message is embedded into an image, then the recipient will need a key to decrypt the message.
  • a technique for providing for secure exchanges of encrypted data such as encryption keys that is known in the art is the use of a trusted third party.
  • the trusted third party essentially acts as a secure broker in exchanging data between two other parties. It is within the scope of this invention to exchange information, such as encryption keys, by use of a trusted third party.

Abstract

L'invention concerne un procédé permettant de masquer des données, qui consiste, à partir d'un message (68) et d'une séquence de cryptage (86), à générer un message crypté (72) sur la base dudit message et de ladite séquence de cryptage. Un signal de porteuse (66), transportant des informations sans rapport avec le message crypté, est généré, puis le message crypté est incorporé (78) au signal de porteuse par une opération OU exclusif du message crypté avec une première partie du signal de porteuse.
PCT/US1998/017321 1997-08-22 1998-08-21 Masquage de donnees cryptees WO1999011020A1 (fr)

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Application Number Priority Date Filing Date Title
US09/485,759 US6912658B1 (en) 1997-08-22 1998-08-21 Hiding of encrypted data

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US5672497P 1997-08-22 1997-08-22
US60/056,724 1997-08-22

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WO1999011020A1 true WO1999011020A1 (fr) 1999-03-04

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001005075A1 (fr) * 1999-07-13 2001-01-18 Microsoft Corporation Filigranage numerique audio ameliore avec voie clandestine et permutations
WO2001086650A1 (fr) * 2000-05-10 2001-11-15 Koninklijke Philips Electronics N.V. Systeme de protection de copie
WO2002029808A2 (fr) * 2000-10-04 2002-04-11 University Of Miami Masquage de voie auxiliaire dans un signal audio
WO2003003744A1 (fr) * 2001-06-28 2003-01-09 Motorola Inc Transmission d'images (video) a filigrane numerique
US6738744B2 (en) 2000-12-08 2004-05-18 Microsoft Corporation Watermark detection via cardinality-scaled correlation
US6952774B1 (en) 1999-05-22 2005-10-04 Microsoft Corporation Audio watermarking with dual watermarks
US7020285B1 (en) 1999-07-13 2006-03-28 Microsoft Corporation Stealthy audio watermarking
US7206649B2 (en) 2003-07-15 2007-04-17 Microsoft Corporation Audio watermarking with dual watermarks
US7886151B2 (en) * 2002-01-22 2011-02-08 Purdue Research Foundation Temporal synchronization of video and audio signals
US8878041B2 (en) 2009-05-27 2014-11-04 Microsoft Corporation Detecting beat information using a diverse set of correlations

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US7020285B1 (en) 1999-07-13 2006-03-28 Microsoft Corporation Stealthy audio watermarking
WO2001006755A2 (fr) * 1999-07-13 2001-01-25 Microsoft Corporation Filigrane numerique audio furetif ameliore
WO2001006755A3 (fr) * 1999-07-13 2001-04-05 Microsoft Corp Filigrane numerique audio furetif ameliore
WO2001005075A1 (fr) * 1999-07-13 2001-01-18 Microsoft Corporation Filigranage numerique audio ameliore avec voie clandestine et permutations
US7552336B2 (en) 1999-07-13 2009-06-23 Microsoft Corporation Watermarking with covert channel and permutations
US7543148B1 (en) 1999-07-13 2009-06-02 Microsoft Corporation Audio watermarking with covert channel and permutations
US7266697B2 (en) 1999-07-13 2007-09-04 Microsoft Corporation Stealthy audio watermarking
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WO2002029808A2 (fr) * 2000-10-04 2002-04-11 University Of Miami Masquage de voie auxiliaire dans un signal audio
US6996521B2 (en) 2000-10-04 2006-02-07 The University Of Miami Auxiliary channel masking in an audio signal
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US6738744B2 (en) 2000-12-08 2004-05-18 Microsoft Corporation Watermark detection via cardinality-scaled correlation
WO2003003744A1 (fr) * 2001-06-28 2003-01-09 Motorola Inc Transmission d'images (video) a filigrane numerique
US7886151B2 (en) * 2002-01-22 2011-02-08 Purdue Research Foundation Temporal synchronization of video and audio signals
US7206649B2 (en) 2003-07-15 2007-04-17 Microsoft Corporation Audio watermarking with dual watermarks
US8878041B2 (en) 2009-05-27 2014-11-04 Microsoft Corporation Detecting beat information using a diverse set of correlations

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