the data encryption standard

... bar code, the other two in hexadecimal: one across the top, and another across the eyes Those numbers were the public key IDs of the faceless persons on the cover Over the photograph was the text, ... hope for the best 3 Data Encryption Standard In the United States, the National Bureau of Standards (NBS) began undertaking an effort aimed at protecting communications data As part of the Department ... Allowing users to choose their own key lengths would allow them to decide for themselves whether the extra security of the larger keys was worth the extra time needed for the encryption and decryption...

Ngày tải lên: 25/03/2014, 11:08

... phụ dùng theo thứ tự ngược lại từ K16 đến K1, nghĩa bước trình mã hoá liệu đầu vào Ri-1 XOR với K17-i với Ki Đặc điểm mã DES Tính chất bù mã DES: DES có tính chất bù: : Ā phần bù A theo bít ... thành xâu có độ dài 48 bit tương ứng với hàm mở rộng E cố định E(Ri) bao gồm 32 bit từ Ri, hoán vị theo cách thức xác định, với 16 bit tạo lần Hàm f (tt.) 32 5 9 10 11 12 13 12 13 14 15 16 17 16 ... 12 14 16 11 13 15 MÔ TẢ THUẬT TOÁN (tt.) Tính 16 vòng lặp hàm xác định Ta tính LiRi với 1

Ngày tải lên: 30/05/2015, 08:06

... output is precisely the bit configuration which was used to encode the other half, with the aid of the particular stage subkey Therefore, by using the subkeys in reverse order, the encryption process ... function f, that combines the data with a 48-bit key, Ki At each stage i, the inputs are the left block Li-1 and the right block Ri-1 of the previous stage, and the outputs are the left shift block ... corresponds to the third row of the S-box The middle 4-bits are combined to form 1001 which corresponds to the ninth column of the for 110010 The substitution boxes are the most critical step in the DES...

Ngày tải lên: 11/01/2016, 11:52

Ngày tải lên: 08/08/2014, 07:22

... CÔNG NGHỆ THÔNG TIN VÀ TRUYỀN THÔNG NGUYỄN THỊ THỦY TÌM HIỂU CHUẨN MẬT MÃ DỮ LIỆU DES (DATA ENCRYPTION STANDARD) VÀ ĐÁNH GIÁ ĐỘ AN TOÀN Chuyên ngành: KHOA HỌC MÁY TÍNH Mã số: 60 48 01 LUẬN VĂN ... tốt? Hiểu đƣợc tính cấp thiết quan trọng nên chọn đề tài “Tìm hiểu chuẩn mật mã liệu DES (Data Encryption Standard) đánh giá độ an toàn” Luận văn đóng góp phần nhỏ vào việc nhìn nhận đánh giá hệ ... đứng đầu từ, tần số ký tự đứng cuối từ Sau kết tính toán tần số đơn tiếng Việt theo kiểu thứ tự, không dấu, có dấu viết theo kiểu điện báo có dấu thông thƣờng Do tiếng việt phức tạp nên việc tính...

Ngày tải lên: 23/12/2014, 10:45

... toán mã hóa tiếng  DES (Data Encryption Standard)  One-time Pad (OTP)  AES (Advance Encryption Standard)  RSA DES | DES | I.GIỚI THIỆU Thuật toán DES (Data Encryption Standard) thuật toán mã ... phổ biến là: DES, AES (Advanced Encryption Standard - Tiêu chuẩn mã hóa nâng cao),… Thuật toán mã hóa khối đời sớm có nhiều ảnh hưởng thuật toán DES (Data Encryption Standard - Tiêu chuẩn mã hóa ... sửa đổi Cục tiêu chuẩn Liên bang Hoa Kỳ thức công nhận thuật toán Lucifer đổi tên thành Data Encryption Standard (DES) vào 15 tháng năm 1977 DES nhanh chóng áp dụng lĩnh vực truyền tín hiệu đường...

Ngày tải lên: 23/05/2015, 10:16

... of Nk then SubWord is applied to Wi−1 prior to the XOR operation From the matrix W , the RoundKeys can be easily extracted The first Nb columns of W form the key for the initial round and the second ... only the inverse of the S-box used for encryption is used, see table InvShiftRows The InvShiftRows operation is equal to the ShiftRows operation, only the shift is to the right instead of to the ... Unlike the design of the S-boxes in the DES algorithm, which is kept secret, the design of the S-box is public The SubBytes transformation is a non-linear byte substitution, operating on each of the...

Ngày tải lên: 22/10/2015, 17:46

... use those data The instantiation of the data model is, in part, the standards for communicating the data, because those standards capture the essential elements within the data to make them useful ... recognize the value of data and those who produce it by enforcing data- reporting standards Because in the end we will all benefit Standards truly make the data we generate better by making sure they ... rationalizing and standardizing them Despite a growing realization that standards are necessary to enable re-use of data, the problem with all of these standards efforts is that they have failed...

Ngày tải lên: 11/08/2014, 12:20

... universal-character-name and “other implementation-defined characters” is new in C99 C++ The C++ Standard uses the term nondigit to denote an identifier-nondigit The C++ Standard does not specify the use of other implementation-defined ... in their usage Identifiers are the most important token in the visible source code from the program comprehension perspective They are also the most common token (29% of the visible tokens in the ... of commonality The greater the number of features different identifiers have in common, the greater the probability that a reader will confuse one of them for the other Minimizing the probability...

Ngày tải lên: 17/10/2013, 19:15

... enumerator, the initializing value has the same type as the expression If no initializer is specified for the first enumerator, the type is an unspecified integral type Otherwise the type is the same as the ... contain either of these suffixes— an unsigned type Because of the behavior of C++, the sequencing of some types on this list has changed from C90 The following shows the entries for the C90 Standard ... knowing the number of nonzero digits before the decimal point and the value of the exponent There are many ways in which these two quantities can be varied and yet always denote the same value Is there...

Ngày tải lên: 20/10/2013, 10:15

... However, these are not related to the mechanisms being described in the C Standard The term exceptional condition is not defined in the C sense Other Languages Few languages define the behavior when the ... table (indexed by the address of the load instruction) If the value eventually returned by the execution of the load instruction is the same as the one looked up, the results of the speculative ... resistance to parenthesizing these operators because they are not usually thought of in these terms (they are not operators in many other languages); they are also unary operators and the pair of characters...

Ngày tải lên: 20/10/2013, 10:15

... result The result of the / operator is the quotient from the division of the first operand by the second; 1148 Commentary The identity 1/∞ ⇒ is consistent with the possibility that the infinity was the ... Like C90, the C++ Standard specifies that the result is a constant The cases where the result is not a constant require the use of types that are not supported by C++ 1122 If the type of the operand ... If the value of the expression is represented with greater precision or range than required by the type named by the cast (6.3.1.8), then the cast specifies a conversion even if the type of the...

Ngày tải lên: 24/10/2013, 08:15

... on the operands Commentary The discussion in the various subsections is the same as that for the bitwise exclusive-OR operator 1247 The result of the | operator is the bitwise inclusive OR of the ... (where the source and destination overlap) where the behavior can vary The result will depend on the relative addresses of the objects and whether the copying starts at the lowest or the highest ... lists all the cases where objects may be adjacent in memory C90 The C90 Standard did not discuss these object layout possibilities C++ The C++ Standard does not make these observations Other Languages...

Ngày tải lên: 24/10/2013, 08:15

... trees They cut the leaves off and carry them underground and then feed the leaves to the fungi the fungi are able to absorb nutrients from the leaves What the ants eat are the fungi that they ... familiar with the test format and how to mark your answers on the answer sheet You can then focus your attention on the questions themselves, rather than on the format • Review carefully the test ... gains in their score if they take a form of the TOEFL Junior Standard test every months or so Before taking the TOEFL Junior Standard test, there are several things you can to prepare for the test...

Ngày tải lên: 26/10/2013, 10:23

... the addresses of the links, in a linked data structure, are often close to the address of the object they refer to (the runtime system checks whether the two addresses have the same top 17 bits) ... reduce the effort needed to comprehend the source and reduce the cost making changes to the value in the future If the value or is stored into a nonzero-width bit-field of type _Bool, the value of the ... representing the values of all the members of the enumeration Commentary This is a requirement on the implementation C90 The requirement that the type be capable of representing the values of all the...

Ngày tải lên: 28/10/2013, 15:15

... if 8.3.5p3 The C++ Standard does not define the term composite type Neither does it define the concept of compatible type, it requires types to be the same The C++ Standard transforms the parameters’ ... occurrences may be the only instance of the constant value in the source, or the values appearing in the list may have semantic or mathematical associations with each other In these cases the guideline ... of the value returned and in the number and type of parameters; the presence or absence of the ellipsis is considered part of the function type 8.3.5p3 631 The C++ Standard does not define the...

Ngày tải lên: 28/10/2013, 15:15

... begin/end pairs) within the then arm For instance, Algol 60 permits the usage IF q1 THEN a1 ELSE IF q2 THEN a2 ELSE a3, but the following is a syntax violation IF q1 THEN IF q2 THEN a1 ELSE a2 ELSE ... equivalent C++ Like the C90 Standard, the C++ Standard specifies the semantics in terms of an equivalent while statement However, the C++ Standard uses more exact wording, avoiding the possible ambiguities ... expressionopt ; Commentary These are all jump statements in the sense they cause the flow of control to jump to another statement (in the case of the goto statement this could be itself) Other Languages Most...

Ngày tải lên: 07/11/2013, 09:15

... Commentary The issues are the same as for object-like macros, with the addition of checks on the parameters Requiring that the parameters be spelled the same, rather than, for instance, that they have ... requirement on the implementation Rationale This is replaced by all the arguments that match the ellipsis, including the commas between them The extent to which the arguments corresponding to the parameter ... to be either 2*f(9) or 2*9*g: there are no clear grounds for making a decision whether the f(9) token string resulting from the initial expansion of f and the examination of the rest of the source...

Ngày tải lên: 07/11/2013, 09:15

... the safety and technical standards set by the authority The ACA works closely with telecommunications suppliers and the community to establish policies, procedures and regulations suited to the ... machines installed by the cabler must meet the ACA’s Labelling Notice requirements The A-Tick is part of those requirements The A-Tick label consists of two parts: the A-Tick Logo and other information ... highlighting the importance of the A-Tick in ensuring consumer confidence in products For more information on these brochures or any other matter, please contact the ACA’s T elecommunications Standards...

Ngày tải lên: 10/12/2013, 02:15

Ngày tải lên: 10/12/2013, 03:15