Source: http://www.google.com/patents/US7539305?ie=ISO-8859-1&dq=7751826
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Patent US7539305 - Schryption method and device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA schryption of a text message is based on a schryption key for defining one or more aspects of an encryption and/or a decryption of the text message. For an encryption of the text message, the schryption key is derived from a user key in the form of an encryption key (e.g., a secret key or a public...http://www.google.com/patents/US7539305?utm_source=gb-gplus-sharePatent US7539305 - Schryption method and deviceAdvanced Patent SearchPublication numberUS7539305 B2Publication typeGrantApplication numberUS 10/794,149Publication dateMay 26, 2009Filing dateMar 5, 2004Priority dateMar 5, 2004Fee statusLapsedAlso published asUS20090010433, US20090110193Publication number10794149, 794149, US 7539305 B2, US 7539305B2, US-B2-7539305, US7539305 B2, US7539305B2InventorsTodd B. SchlomerOriginal AssigneeInternational Business Machines CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (9), Classifications (4), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetSchryption method and deviceUS 7539305 B2Abstract A schryption of a text message is based on a schryption key for defining one or more aspects of an encryption and/or a decryption of the text message. For an encryption of the text message, the schryption key is derived from a user key in the form of an encryption key (e.g., a secret key or a public key), and the text message in the form of plaintext is encrypted as defined, at least partially, by the schryption key to thereby yield a ciphertext. For a decryption of the text message, the schryption key is derived from user key in the form of a decryption key (e.g., a secret key or a private key), and the text message in the form of a ciphertext is decrypted as defined, at least partially, by the schryption key to thereby yield a plaintext.
FIELD OF INVENTION The present invention generally relates to cryptography and cryptanalysis. The present invention specifically relates to dynamic key-based cipher methods for minimizing, if not eliminating, successful retrieval by cryptanalysts of plaintext from ciphertext.
The first class is symmetric key-based cipher methods that are based on using a secret key or a key randomly derived from the secret key for both encryption and decryption, or using the secret key or the key randomly derived from the secret key for both encryption only while deriving the decryption key from the encryption key. Some well known symmetric key-based cipher methods are Data Encryption Standard (�DES�), Advanced Encryption Standard (�AES�), the One-Time Pad (�OTP�), Blowfish, IDEA and RC4.
The second class is asymmetric key-based cipher methods that are based on using a different key for encryption and decryption where the decryption key (a.k.a. the �private key�) cannot be derived from the encryption key (a.k.a. the �public key)�. Some well known asymmetric key-based cipher methods are Rivest-Shamir-Adleman (�RSA�) and Rabin.
SUMMARY OF THE INVENTION The present invention provides a new and unique key-based cipher method known herein as �schryption� that minimizes, if not eliminates, any cryptanalysis attack on computer software and/or its underlying computer hardware for implementing the key-based cipher method, and specialized hardware devices for implementing the key-based cipher method.
The terms �text message�, �plaintext� and �ciphertext� shall encompass any and every type of data, including, but not limited to, plain data strings, emails, files and otherwise other communications involving well known applications, such as, for example, secure messaging, authentication, digital signatures and electronic money.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a flowchart representative of schryption method in accordance with an encryption embodiment of the present invention;
DESCRIPTION OF THE PREFERRED EMBODIMENT Schryption encompasses a key-based cipher method involving a dynamic generation of schryption keys, on a stream, block or unit basis, from a cipher key in the form of either an encryption key or a decryption key, where the cipher key is associated with a symmetric implementation of the cipher method (e.g., a secret key) or an asymmetric implementation of the cipher method (e.g., a public key or a private key). Each generated schryption key defines one or more aspects of an encryption of a plaintext, and/or a decryption of a ciphertext. To facilitate an understanding of the present invention, FIG. 1 illustrates a flowchart 20 representative of a baseline schryption method for encrypting a plaintext, FIG. 3 illustrates a flowchart 30 representative of a baseline schryption method for decrypting a ciphertext, and FIG. 5 illustrates a flowchart 50 representative of a total schryption method for encrypting and decrypting a text message in the form of a plaintext or a ciphertext.
Referring to FIG. 5, during a stage S42 of flowchart 40 a text message in the form of a plaintext or a ciphertext, and a user key in the form of a secret key SEK are received. While the text message and the user key in practice can contain any number of bits, for purposes of facilitating an understanding of flowchart 40, text message contains twenty (20) bytes corresponding to �PASSWORD: SCHRYPTION� and secret key SEK is exemplary illustrated in FIG. 6 as containing nine (9) bytes corresponding to �SECRET KEY�.
During a stage S44 of flowchart 40, an original master key MSK1 is generated as a function of secret key SEK and a base key BSK. While base key BSK in practice can contain any number of bits, base key BSK is exemplary illustrated in FIG. 6 as containing seven (7) bytes corresponding to �BASE KEY� for purposes of facilitating an understanding of flowchart 40.
For purposes of facilitating an understanding of flowchart 40, control segment CSG exemplary specifies ten (10) byes of the text message to be ciphered, which results in text message block TMB1 of �PASSWORD:_� as exemplary illustrated in FIG. 6. Furthermore, parameter bytes PM1-PM5 are processed through a mathematical algorithm to yield a single parameter byte PM6 as exemplary illustrated in FIG. 6.
During a stage S48 of flowchart 40, text message block TMB1 of �PASSWORD:_� is ciphered as defined, in part, by schryption key SHK3 to yield a cipher message CMI. In one exemplary embodiment, parameter byte PM6 is XORed with each byte of text message block TMB1 for a specific number of times as specified by control segment CSH of schryption key SHK3 (e.g., three (3) times) to thereby yield cipher message CMI of �$@%^HGQ76� as exemplary illustrated in FIG. 6.
During a stage S50 of flowchart 40, it will be determined that additional bytes �SCHRYPTION� of text message have not been ciphered. Flowchart 40 therefore proceeds to a stage S52 of flowchart 40 to generate a new master key MSK2 as a function of master key MSK1, base key BSK and schryption key SHK3. In practice, the algorithm for generating master key MSK2 as a function of master key MSK1, base key BSK and schryption key SHK3 is without limit, and is therefore not a limitation as to the scope of stage S52. In one exemplary embodiment of stage S52, each byte of master key MSK1 is XORed with base key BSK for a specific number of times as specified by control segment CSI of schryption key SHK3 to thereby yield master key MSK2 as exemplary illustrated in FIG. 7.
For flowchart 40, the crypt ion function is a XOR function whereby control segment CSJ specifies the number of bytes of the text message to be ciphered, and control segment CSK specifies the number of times the XOR function is to be executed. For purposes of facilitating an understanding of flowchart 40, control segment CSJ exemplary specifies ten (10) byes of the text message to be ciphered, which results in text message block TMB2 of �SCHRYPTION� as exemplary illustrated in FIG. 7. Furthermore, parameter bytes PM7-PM11 are processed through a mathematical algorithm to yield a single parameter byte PM12 as exemplary illustrated in FIG. 7.
During stage S48, text message block TMB2 of �SCHRYPTION� is ciphered as defined, in part, by schryption key SHK4 to yield a cipher message block CMB2. In one exemplary embodiment, parameter byte PM12 is XORed with each byte of text message block TMB2 for a specific number of times as specified by control segment CSK of schryption key SHK4 (e.g., three (3) times) to thereby yield cipher message block CMB2 of �4f*9S!B %+=� as exemplary illustrated in FIG. 7.
During a stage S50 of flowchart 40, it will be determined that there are no additional bytes of the text message to cipher, and flowchart 40 is therefore terminated whereby cipher message blocks CMB1 and CMB2 are combined to yield a cipher message �$@%^!HGQ764f*9S!B %+=�. Those having ordinary skill in the art will appreciate that a sequent and identical execution of flowchart 40 on cipher message �$@%^!HGQ764f*9S!B %+=� will yield text message �PASSWORD: SCHRYPTION�. Those having ordinary skill in the art will therefore further appreciate, from an execution of flowchart 40, the new and unique encryption security obtained in the concealment of text message �PASSWORD: SCHRYPTION� within cipher message �$@%^!HGQ764f*9S!B %+=�, and new and unique description security obtained in the retrieval of text message �PASSWORD: SCHRYPTION� from cipher message �$@%^!HGQ764f*9S!B %+=�.
The description of flowchart 40 herein in the context of ciphering �PASSWORD: SCHRYPTION� was given to facilitate an understanding of a total schryption method of the present invention. In practice, the sequence of stages S44-S52 of flowchart 40 can be implemented under different schemes for ciphering �PASSWORD: SCHRYPTION�.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3798360Jun 30, 1971Mar 19, 1974IbmStep code ciphering systemUS5003596 *Aug 17, 1989Mar 26, 1991Cryptech, Inc.Method of cryptographically transforming electronic digital data from one form to anotherUS5548648Jul 15, 1994Aug 20, 1996International Business Machines CorporationEncryption method and systemUS5805705Jan 29, 1996Sep 8, 1998International Business Machines CorporationSynchronization of encryption/decryption keys in a data communication networkUS6192129Feb 4, 1998Feb 20, 2001International Business Machines CorporationMethod and apparatus for advanced byte-oriented symmetric key block cipher with variable length key and blockUS6363148Nov 13, 1997Mar 26, 2002Sony CorporationMethod, apparatus and computer program for activating an alternate encryption using an identifier embedded in dataUS6490353Nov 23, 1998Dec 3, 2002Tan Daniel Tiong HokData encrypting and decrypting apparatus and methodUS20020159598Dec 7, 2001Oct 31, 2002Keygen CorporationSystem and method of dynamic key generation for digital communicationsWO2001001223A1Jun 23, 2000Jan 4, 2001Centura SoftwareTwo-layer encryption of databases* Cited by examinerClassifications U.S. Classification380/28International ClassificationH04L9/28Cooperative ClassificationH04L9/00European ClassificationH04L9/00Legal EventsDateCodeEventDescriptionJul 16, 2013FPExpired due to failure to pay maintenance feeEffective date: 20130526May 26, 2013LAPSLapse for failure to pay maintenance feesJan 7, 2013REMIMaintenance fee reminder mailedMar 5, 2004ASAssignmentOwner name: INTERNATIONAL BUSINESS MACHINES CORPORATION, NEW YFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SCHLOMER, TODD B.;REEL/FRAME:015064/0525Effective date: 20040304RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google