Patents by Inventor Litao Shen
Litao Shen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11818264Abstract: Disclosed are various embodiments for implementing a key escrow system without disclosure of a client's encryption key to third parties. An encryption key is split into a plurality of key segments pursuant to a shared secret protocol. A plurality of peer client devices are then identified. Each peer client device in the plurality of peer client devices is then verified and the respective one of the plurality of key segments are sent to a respective one of the plurality of peer client devices. A response is then received from each respective one of the plurality of peer client devices, the response confirming receipt of the respective one of the plurality of key segments. A list identifying the plurality of peer client devices is finally provided to a key escrow service, the list comprising key-value pairs that identify each respective one of the plurality of peer client devices and the respective one of the plurality of key segments.Type: GrantFiled: June 22, 2021Date of Patent: November 14, 2023Assignee: VMWARE, INC.Inventors: Chaoting Xuan, Qimin Yao, Litao Shen
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Publication number: 20210314153Abstract: Disclosed are various embodiments for implementing a key escrow system without disclosure of a client's encryption key to third parties. An encryption key is split into a plurality of key segments pursuant to a shared secret protocol. A plurality of peer client devices are then identified. Each peer client device in the plurality of peer client devices is then verified and the respective one of the plurality of key segments are sent to a respective one of the plurality of peer client devices. A response is then received from each respective one of the plurality of peer client devices, the response confirming receipt of the respective one of the plurality of key segments. A list identifying the plurality of peer client devices is finally provided to a key escrow service, the list comprising key-value pairs that identify each respective one of the plurality of peer client devices and the respective one of the plurality of key segments.Type: ApplicationFiled: June 22, 2021Publication date: October 7, 2021Inventors: Chaoting Xuan, Qimin Yao, Litao Shen
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Patent number: 11075755Abstract: Disclosed are various embodiments for implementing a key escrow system without disclosure of a client's encryption key to third parties. An encryption key is split into a plurality of key segments pursuant to a shared secret protocol. A plurality of peer client devices are then identified. Each peer client device in the plurality of peer client devices is then verified and the respective one of the plurality of key segments are sent to a respective one of the plurality of peer client devices. A response is then received from each respective one of the plurality of peer client devices, the response confirming receipt of the respective one of the plurality of key segments. A list identifying the plurality of peer client devices is finally provided to a key escrow service, the list comprising key-value pairs that identify each respective one of the plurality of peer client devices and the respective one of the plurality of key segments.Type: GrantFiled: April 24, 2019Date of Patent: July 27, 2021Assignee: VMWARE, INC.Inventors: Chaoting Xuan, Qimin Yao, Litao Shen
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Publication number: 20200344054Abstract: Disclosed are various embodiments for implementing a key escrow system without disclosure of a client's encryption key to third parties. An encryption key is split into a plurality of key segments pursuant to a shared secret protocol. A plurality of peer client devices are then identified. Each peer client device in the plurality of peer client devices is then verified and the respective one of the plurality of key segments are sent to a respective one of the plurality of peer client devices. A response is then received from each respective one of the plurality of peer client devices, the response confirming receipt of the respective one of the plurality of key segments. A list identifying the plurality of peer client devices is finally provided to a key escrow service, the list comprising key-value pairs that identify each respective one of the plurality of peer client devices and the respective one of the plurality of key segments.Type: ApplicationFiled: April 24, 2019Publication date: October 29, 2020Inventors: Chaoting Xuan, Qimin Yao, Litao Shen
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Patent number: 10544119Abstract: The present invention relates to a preparation method for a chiral intermediate for use in statins, acquired with chloroacetic acid and benzyl alcohol as starting materials via a series of reactions, namely etherification, condensation, substitution, and asymmetric reduction. The preparation method provided in the present invention has a novel route of synthesis, allows an intermediate compound to be introduced conveniently into the chiral center of a glycol via enzyme reduction, and not only is low in costs, but also is reliable in quality. The route of synthesis provided in the present invention uses raw materials of low costs, has an easy to operate process, and provides a final product of great purity and high yield.Type: GrantFiled: August 4, 2014Date of Patent: January 28, 2020Assignees: Asymchem Laboratories (Tianjin) Co., Ltd., Asymchem Life Science (Tianjin) Co. Ltd., Tianjin Asymchem Pharmaceutical Co., Ltd., Asymchem Laboratories (Fuxin) Co., Ltd., Jilin Asymchem Laboratories Co., Ltd.Inventors: Hao Hong, Chaoyong Chen, Jiuyuan Li, Litao Shen, Lina Guo, Hongying Tian
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Patent number: 10246524Abstract: A method for preparing sulfobutyl ether-?-cyclodextrin. ?-cyclodextrin and 1,4-sulfobutyrolactone are used as raw materials, and a proper amount of an organic solvent is introduced into an alkaline aqueous solution, so that the solubility of the 1,4-sulfobutyrolactone is increased, and the synthesis yield of the sulfobutyl ether-?-cyclodextrin is improved. Operations including ultrasonic dialysis, active carbon decoloration, freeze-drying and so on are performed on the obtained product solution, so as to obtain a powder product of the sulfobutyl ether-beta-cyclodextrin.Type: GrantFiled: October 14, 2014Date of Patent: April 2, 2019Assignee: ASYMCHEM LABORATORIES (TIANJIN) CO., LTD.Inventors: Hao Hong, Changfeng Li, Litao Shen
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Patent number: 9926283Abstract: Provided are an intermediate compound for preparing rosuvastatin calcium and a preparation method of the rosuvastatin calcium. The method comprises: using the foregoing intermediate compound as a raw material, and subjecting the raw material to a step of Wittig reaction, a step of protecting group removal and hydrolysis and a step of calcium salt formation, so as to obtain the rosuvastatin calcium. The product, which is prepared from the intermediate compound, can be substantially enhanced in stereoselectivity and also notably improved in purity and yield; in addition, the method for preparing rosuvastatin calcium from the intermediate compound is simple, convenient and low in cost.Type: GrantFiled: March 7, 2014Date of Patent: March 27, 2018Assignees: Asymchem Laboratories (Tianjin) Co., Ltd., Asymchem Life Science (Tianjin) Co., Ltd., Tianjin Asymchem Pharmaceutical Co., Ltd., Asymchem Laboratories (Fuxin) Co., Ltd., Jilin Asymchem Laboratories Co., Ltd.Inventors: Hao Hong, James Gage, Jiuyuan Li, Litao Shen, Lei Zhang, Changming Dong
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Publication number: 20170190684Abstract: The present invention relates to a preparation method for a chiral intermediate for use in statins, acquired with chloroacetic acid and benzyl alcohol as starting materials via a series of reactions, namely etherification, condensation, substitution, and asymmetric reduction. The preparation method provided in the present invention has a novel route of synthesis, allows an intermediate compound to be introduced conveniently into the chiral center of a glycol via enzyme reduction, and not only is low in costs, but also is reliable in quality. The route of synthesis provided in the present invention uses raw materials of low costs, has an easy to operate process, and provides a final product of great purity and high yield.Type: ApplicationFiled: August 4, 2014Publication date: July 6, 2017Applicants: Asymchem Laboratories (Tianjin) Co., Ltd., Asymchem Life Science (Tianjin) Co., Ltd., Tianjin Asymchem Pharmaceutical Co., Ltd., Asymchem Laboratories (Fuxin) Co., Ltd., Jilin Asymchem Laboratories Co., Ltd.Inventors: Hao Hong, Chaoyong Chen, Jiuyuan Li, Litao Shen, Lina Guo, Hongying Tian
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Publication number: 20170022169Abstract: Provided are an intermediate compound for preparing rosuvastatin calcium and a preparation method of the rosuvastatin calcium. The method comprises: using the foregoing intermediate compound as a raw material, and subjecting the raw material to a step of Wittig reaction, a step of protecting group removal and hydrolysis and a step of calcium salt formation, so as to obtain the rosuvastatin calcium. The product, which is prepared from the intermediate compound, can be substantially enhanced in stereoselectivity and also notably improved in purity and yield; in addition, the method for preparing rosuvastatin calcium from the intermediate compound is simple, convenient and low in cost.Type: ApplicationFiled: March 7, 2014Publication date: January 26, 2017Applicants: Asymchem Laboratories (Tianjin) Co., Ltd., Asymchem Life Science (Tianjin) Co., Ltd., Tianjin Asymchem Pharmaceutical Co., Ltd., Asymchem Laboratories (Fuxin) Co., Ltd., Jilin Asymchem Laboratories Co., Ltd.Inventors: Hao HONG, James GAGE, Jiuyuan LI, Litao SHEN, Lei ZHANG, Changming DONG
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Publication number: 20160326270Abstract: A method for preparing sulfobutyl ether-?-cyclodextrin. ?-cyclodextrin and 1,4-sulfobutyrolactone are used as raw materials, and a proper amount of an organic solvent is introduced into an alkaline aqueous solution, so that the solubility of the 1,4-sulfobutyrolactone is increased, and the synthesis yield of the sulfobutyl ether-?-cyclodextrin is improved. Operations including ultrasonic dialysis, active carbon decoloration, freeze-drying and so on are performed on the obtained product solution, so as to obtain a powder product of the sulfobutyl ether-beta-cyclodextrin.Type: ApplicationFiled: October 14, 2014Publication date: November 10, 2016Applicant: ASYMCHEM LABORATORIES (TIANJIN) CO., LTDInventors: Hao Hong, Changfeng Li, Litao Shen