Abstract:
The described implementations relate to establishing authenticated communication between a client computing device and a service provider. In one implementation, once a registration procedure is complete, multiple authentication servers are used by a client computing device and a service provider to facilitate the establishment of an authenticated communication session. However, the authentication servers are not necessarily trusted authorities. That is, secrets of the various described devices are not revealed to each other.
Abstract:
A method and system is provided for encrypting an image compressed with a JPEG2000-based compression with minimal overhead so that the encrypted codestream is compliant with the syntax of the JPEG2000-based compression and can be scaled without decrypting. The encryption system generates, for each independent encryption segment of a codestream for an image, a unique initialization vector from a global initialization vector in such a way that the initialization vectors can be generated during decryption from the global initialization vector, even after truncation. The encryption system encrypts each independent encryption segment using its unique initialization vector. The encryption system ensures that the encrypted codestream is compliant with the syntax of the JPEG2000-based compression both as originally generated and as truncated by an encryption-unaware device.
Abstract:
Systems and methods providing ciphertext switching for syntax compliant encryption are described. In one aspect, intermediate ciphertext is generated from syntax compliant plaintext. Post-processing is applied to the intermediate ciphertext to determine if there are any illegal symbols in the intermediate ciphertext. If an illegal symbol is located, the illegal symbol in the intermediate ciphertext is switched with a corresponding plaintext symbol. One or more iterations of the post-processing and switching operations result in syntax compliant ciphertext.
Abstract:
Transactional watermarking is disclosed. In one embodiment, a computer-implemented method includes receiving an original multimedia content source. The original multimedia content source may have already had a watermark added thereto. The method watermarks at least a portion of the source at least two times, each time with a different watermark to generate a different watermarked version of the original multimedia content source. A final watermarked content source is then generated by utilizing the different watermarked versions of the content source. One particular version of the watermarked content source may be selected as the final watermarked content source; at least a portion of at least two of the different watermarked versions of the watermarked content source may be combined to generate the final watermarked content source; etc.
Abstract:
Disclosed is a modified zeolite catalyst for the liquid phase alkylation and transalkylation of benzene comprising 30 to 70% by weight of H-beta zeolite with a silicon to aluminium ratio of 20 to 40; 0.5 to 10% by weight of halogen; and .gamma.-Al.sub.2 O.sub.3 of the balance. Also disclosed a method for preparing the said catalyst comprising adding a halogen-containing compound to a mixture of H-beta zeolite and a precursor of .gamma.-Al.sub.2 O.sub.3, forming followed by calcining.
Abstract translation:公开了用于苯的液相烷基化和烷基转移的改性沸石催化剂,其包含30至70重量%的硅铝比为20至40的H-β沸石; 0.5〜10重量%的卤素; 和余量的γ-Al2O3。 还公开了一种制备所述催化剂的方法,包括向H-β沸石和γ-Al 2 O 3的前体的混合物中加入含卤素化合物,随后煅烧形成。
Abstract:
A flow control device including a flow channel having a housing defining an inside surface, the inside surface having an irregular helical structure of constant orthogonal cross-sectional dimensions.
Abstract:
The invention discloses method for determining hydraulic parameters and water inflow in the erosion stage of gravel soil, comprising: calculate the soil particle content P and the soil porosity n of each grade of particle size a, and draw the PSD curve of each grade of particle size and the soil particle content P of each grade of particle size and the PSD curve cluster of each grade of particle size and the soil particle content P of each grade of particle size in each erosion stage; calculate the equivalent diameter Dh of the soil particle, and calculate the minimum equivalent pore diameter d0 of the soil particle; calculate the critical hydraulic gradient icr of particle erosion at each stage; calculate the permeability coefficient kh; calculate the seepage flow velocity ν and the total seepage flow Q.
Abstract:
The overlay human interactive proof system (“OHIPS”) and techniques described herein operate in conjunction with any known or later developed computer-based applications or services to provide secure access to resources by reliably differentiating between human and non-human users. Humans have a generally superior ability to differentiate misaligned characters or objects from correctly aligned ones. As such, the OHIP splits an image including one or more visual objects into two or more partial images to form a HIP. The partial images may also be further split into groups of sub-partial images, and/or the partial images (or the sub-partial images) may be moved, so that at any given alignment position, a user can recognize only some visual objects. A user is instructed to reassemble the partial images at one or more predetermined alignment positions using a GUI, and the user is asked to identify information regarding one or more visible objects.
Abstract:
A method for disassembling an executable binary (binary). In one implementation, a plurality of potential address references may be identified based on the binary and a plurality of storage addresses containing the binary. A plurality of assembler source code instructions (instructions) may be generated by disassembling the binary. The binary may be disassembled at one or more sequential addresses starting at each of the plurality of potential address references.
Abstract:
A process for producing an alkylene oxide by olefin epoxidation, wherein said process comprises the steps of: (1) in a first olefin epoxidation condition, in the presence of a first solid catalyst, a first mixed stream containing a solvent, an olefin and H2O2 is subjected to an epoxidation in one or more fixed bed reactors and/or one or more moving bed reactors until the conversion of H2O2 reaches 50%-95%, then, optionally, the resulting reaction mixture obtained in the step (1) is subjected to a separation to obtain a first stream free of H2O2 and a second stream containing the unreacted H2O2, and the olefin is introduced to the second stream to produce a second mixed stream, or optionally, the olefin is introduced to the reaction mixture obtained in the step (1) to produce a second mixed stream; (2) in a second olefin epoxidation condition, the reaction mixture obtained in the step (1) or the second mixed stream obtained in the step (1) and a second solid catalyst are introduced to one or more slurry bed reactors to conduct an epoxidation until the total conversion of H2O2 reaches 98% or more, with a proviso that said process for producing the alkylene oxide by olefin epoxidation has an selectivity for the alkylene oxide of 90% or more.The process of the present invention combines the slurry bed reactor with the fixed bed reactor and/or the moving bed reactor so as to overcome the disadvantages of the low conversion of H2O2 in the case that only the fixed bed reactor and/or the moving bed reactor are used, and the low selectivity for the target alkylene oxide in the case that only the slurry bed reactor is used.
Abstract translation:一种通过烯烃环氧化生产烯化氧的方法,其中所述方法包括以下步骤:(1)在第一烯烃环氧化条件下,在第一固体催化剂存在下,将含有溶剂,烯烃和H 2 O 2的第一混合物流 在一个或多个固定床反应器和/或一个或多个移动床反应器中进行环氧化,直到H 2 O 2的转化率达到50%-95%,然后,任选地,将在步骤(1)中获得的所得反应混合物 以分离以获得不含H 2 O 2的第一物流和含有未反应的H 2 O 2的第二物流,并将烯烃引入第二物流以产生第二混合物流,或任选地将烯烃引入到 步骤(1)以产生第二混合流; (2)在第二烯烃环氧化条件下,将步骤(1)中获得的反应混合物或步骤(1)中获得的第二混合物流和第二固体催化剂引入一个或多个淤浆床反应器中进行环氧化 直到H 2 O 2的总转化率达到98%以上,条件是通过烯烃环氧化生产环氧烷烃的方法对环氧烷烃的选择性为90%以上。 本发明的方法将淤浆床反应器与固定床反应器和/或移动床反应器结合,以克服在只有固定床反应器和/或移动床的情况下H 2 O 2转化率低的缺点 使用反应器,在仅使用浆料床反应器的情况下对目标烯化氧的选择性低。