Cryptography: Theories, Functions and Strategies

Cryptography Theories, guides and StrategiesAbstractDigital signing is a mechanism for certifying the origin and the integrity of electronic for each one(prenominal)y transmitted schooling. In the assist of digitally signing, additional instruction called a digital come upon sig temperament is added to the aband superstard document, calculated using the contents of the document and round unavowed cay. At a later stage, this development raise be utilize to stop consonant the origin of the signed document. The mathematical base of the digital signing of documents is cosmos learn steganography.This work presents the theory shadower digital spots, signature schemes and attacks on signatures and go a rooms a survey of application argonas of the digital signing technology. Moreover, there be lab exercises developed in Mathlab, to reinforce the understanding of this technology.1. foundingThe crisp Oxford Dictionary (2006) defines cryptography as the art of writing or resolving power codes, however modern cryptography does not met this definition. Therefore, this work starts with a books review defining some key concepts, corresponding what cryptography and cryptological scheme atomic amount 18 and the different types of cryptological system are presented. The early(a) interesting and preliminary concept is the notion of cryptosystem subroutines which are also discussed in the introductory section. Furthermore, it is stated that public-key encryption represents a revolution in the depicted object of cryptography, and this work poses some basic definitions on this topic trying to relieve the theory behind. The rest of the literature review is concentrated on public key cryptography and it foc subprograms on the theory behind digital signatures, signature schemes and attacks on signatures. And finally, the literature review presents a survey of application areas on digital signatures.One bring out of the contribution of this work, is an overview of the secure hashish trite (SHS) and implementation of the secure hash algorithmic rule (SHA-1), required for utilization with digital signature algorithms. The main part though, is the implementation of AES and RSA by utilizing Mathlab. The code of all these implementations is thoroughly discussed and explained in this work. Moreover, a comparison is also presented subsequently.2. CryptographyThe Grecian spoken communication kryptos standing for hidden and the word logos that nub word, are in internality the base from where the word coding was derived. As these words denote, steganography muckle be best explained by the significance hidden word. In this context, the buff purpose behind cryptology is hiding the meaning of some specific combination of words which in turn would insure secrecy and confidentiality. This is a very restrain viewpoint in todays perspective and a handsome range of security applications and issues now come under the term of cryptology (rest of the portion of this section volition clarify this point of view). As vault of heaven of mathematical apprehension, Cryptology includes the study of both inexplicable writing as swell up as cryptography. On unmatched hand, cryptography is a very broad term and represents either(prenominal) process utilize for data protection. On the opposite hand, the study of security related issues and the probabilities of breaking the cryptological systems and a proficiency is cognize as cryptanalysis. By making reference to (Shirey, 2000), the field cryptanalysis can be best described as the mathematical science that deals with analysis of a cryptographic system in order to understand fellowship indispensabilityed to break or circumvent the protection that the system is designed to provide. In simple words, cryptanalyst can be loveed as the opponent of the cryptologist i.e. he/she has to get around the security which cryptographer devised on his/her part.(B uchmann, 2004) claims that a cryptographic system (or in short a cryptosystem) describes a set of cryptographic algorithms together with the key management processes that concentrate employ of the algorithms in some application context. This is a diverse translation that includes all sorts of cryptographic algorithms as well as protocols. However, hidden parameters like cryptographic keys may or may not be utilize by a cryptographic system (Delfs, 2007). Similarly, participants of the undergoing communication may or may not share those recondite parameters. Thus, cryptographic can be classified into following three types a cryptographic system in which no secret parameters are employed (called an un-keyed cryptosystem) a cryptosystem which makes use of secret parameters and at the similar time shares the parameters between the participants (known as a secret key cryptographic system) and a system that utilizes the secret parameters, but not sharing them with the participants ( called a public key cryptographic system) (Shirey, 2000 Buchmann, 2004).Cryptography aims at designing and implementing cryptographic systems and utilizing such(prenominal)(prenominal) systems which are secure effectively. The inaugural off a ca-caal definition about the term cryptography dates from relatively gone time. Back thence, the approach known by the name security by obscurity was be utilise (Dent, 2004). There are a apportion of examples based on this approach by which security of the system was improve by keeping internal working and design secret. Majority of those systems do not serve the purpose and security may well be violated. The Kerckhoffs principle is a very famous cryptographic principle which states that (Kerckhoffs, 1883) notwithstanding for parameters clearly defined to be secret, like the cryptographic keys, a cryptosystem essential be designed in such a guidance as to be secure even with the causa that the antagonist knows all exposit about t he system.However, it might be noted that one weighty aspect is that a cryptosystem is perfectly securing theoretically grounds, but it may not pillow the same when implemented practically. Different possibilities of generating attacks on security of such systems can arise while having the practical implementation (Anderson, 1994). Attacks which make use of exploitation of side channel info are the examples of such attacks. If a cryptosystem is executed, it can result in the retrieval of side channel information with unspecified scuttlebutts and outputs (Anderson, 1994). In encryption systems, the input is plaintext heart plus the key, while the specific output is the cipher text. Thus, there are dismissangerments on information leakage. Power consumption, timing characteristics along with the radiation of all types are some examples in this regard. On the former(a) hand, side channel attacks are the types of communicate attacks which extract side channel information. Sin ce the mid 1990s there were legion(predicate) different possibilities impart been found by the researchers in order to gird up side channel attacks. A few examples in this regard are the differential power analysis (Bonehl, 1997), and fault analysis (Biham, 1997 Kocher, 1999) as well as the timing attacks (Kocher, 1996). It is a very practical financial statement that any computation performed on authoritative computer systems represents some bodily phenomena which can be examined and analyzed to provide information regarding the keying material existence employed. Cryptography does not help to cope with this situation because of the inherent nature of this problem.2.1 Cryptosystem unravelsOther than the usual random bit generators as well as the hash runs, there are no secret parameters that are utilise in cryptosystem maps. These are the junketed forges that characterize the cryptographic system endures. In cryptographic survives, the elements utilise are usually o ne-way and it is difficult or approximately im likely to invert them. This follows that it is easy to compute a cryptographic function whereas it is hard to invert the functions and also to compute the results of the relationships (Kerckhoffs, 1883). It is difficult to apply any mathematical method for inverting the cryptographic system functions in a way that will be coherent and meaningful. For example, a cryptographic system functions such as F X Y is easy to comfortably use mathematical knowledge to compute while it is hard to use the same to invert (Buchmann, 2004 Shirey, 2000).There are many examples of one-way functions that we can use to demonstrate the meaning of the cryptosystems. In a situation where one has stored amount on the cell phone, computation of the same is accomplishable and easy payable to the fact that the names are stored in an alphabetical manner (Garrett, 2001). If one inverts the relationship of these functions, it will be impossible to compute becau se the lists are not arranged numerically in the storage phonebook. It is notable that a lot of other things that we do in daily life are comparable to cryptosystem function in the sense that you cannot invert or tease apart them. For example, if one breaks a glass, the process is one way because it is not possible for these pieces to be restored together again (Goldreich, 2004). Similarly, when one drops something into water, it is not practically possible to reverse the natural process of dropping this item (Mao, 2003). The English corresponding action would be to un-drop the item as opposed to picking it. Cryptosystem functions cannot be demo as purely one-way and this is the branching point between cryptosystem functions and the real world of things and circumstances. The only one-way functions in mathematics can be exemplified by discrete exponentiation, modular power and modular square functions. state-supported key cryptography uses these functions in its operations but it has not been well documented whether they are really one-way or not. There has been contest in practice whether one-way functions really exist in the first place or not (Garrett, 2001). In the recent day cryptographic discussions a lot of care should be applied when referring to the one-way functions so as not to interfere or make false claims to the practicable attributes of these parameters. There is a need to look for extra information and knowledge concerning one-way functions so that efficient and meaningful inversions are possible and mathematically coherent.Therefore, functions such as F X Y is considered to be a one-way function (Koblitz, 1994 Schneier, 1996). This follows that if F can successfully and coherently inverted, the need for extra information is needed. This will hence bring the notion of the meaning of the other parameters in relation to F. Computer science uses the hash functions in its operations. This is because these functions are computable and genera tes output dependent on the input that was used (Katz, 2007 Koblitz, 1994).3. Digital signaturesThe public-key encryption presents a revolution in the field of cryptography and until its invention the cryptographers had relied completely on common, secret keys in order to compass confidential communication (Smart, 2003). On the contrary, the public-key techniques, allow for the parties to communicate privately without the sine qua non to decide on a secret key in advance. opus the concept of private-key cryptography is presented as cardinal parties agree on a secret keyk which can be used (by either party) for both encryption and decryption public-key encryption is asymmetric in both these respects (Stinson, 2005). separately, in public-key encryptionOne party (the receiver) generates a pair of keys (pk, sk), where pk is called the public key and ps is the private key,The public key is used by a sender to encrypt a pass on for the receiver, andThe receiver uses the private ke y to decrypt that message.There three parts of information form part of public key certificateSome naming informationA Public keyDigital signatures (this can be one or more)Encryptions and digital signatures were introduced to make the web transactions secure and manageable. The use of cryptographic techniques was applied to enhance and provide security layer such that the encrypted information and records would remain secure and confidential. Very frequently, a digital signature is monstrous with the opposite of a public-key encryption, but this is not entirely true. In the history, a digital signature could be obtained by reversing, but today in the majority of the situations this process would be impossible to be performed.Basically, a digital signature is a form of a mathematical scheme for signifying the legitimacy of a digital message. A valid digital signature would provide a proof to the person that receives the message or the document that these information is indeed c onstituted by a specified sender. Moreover, it would prove that message or the document was not altered during the transportation. Digital signatures are usually used for software distribution or mainly money transactions, where it is very outstanding to detect the possibility of forgery.As a part of the field in asymmetric cryptography, it might be noted that a digital signature is somehow equivalent of the traditional handwritten signatures. On the other hand, in order to be effective, a digital signature should be aright implemented. Another very important concept is the notion of non-repudiation. This means that if mortal signs a document by using a digital signature, they can not say that it was not signed by them, even though their private key remains as a secret. On the other hand, there is a time stamp, so that even if the private key of a sender is compromised in future, the digital signature will remain valid. Examples of such messages areelectronic mailcontractsmessage s sent via some cryptographic protocolA digital signature usually is comprised ofAn algorithm for producing a key. This algorithm would find a private key by chance from all the possible private keys available. Then it will output that private key with a matching public key.A signing algorithm that, disposed(p) a message and a private key, produces a signature.A signature authenticating algorithm that, given a message, public key and a signature, it will accept or reject the message.Primary, a signature produced from a fixed message and a private key verifies that the genuineness of that message is ok, by means of the matching public key. Then, it has to be computationally impossible to make an appropriate signature for a party that doesnt have the private key4. algorithmic rules4.1. Introduction to SHSThis section provides an overview of the secure hash banal (SHS) and implementation of the secure hash algorithm (SHA-1), required for use with digital signature algorithms.SHA-1 is used for computing a compressed version of a message or a data wedge. If that data has a distance smaller than 264 buts, then the output will be 160-bit and is called a message nominate. The message stand out used for an input to the Digital call attentionature Algorithm (DSA). This algorithm will verify the signature for the message. Signing the message offer instead of the originall message itself, might advance the effectiveness of the procedure. This is since the message digest is usually much slighter in size than the original message. Very important is that the same hash algorithm should be used by both the verifier and the digital signature creator.The usage of the SHA-1 with the DSA can be presented as followsInteresting for SHA-1 is that it is computationally impossible to discover a message which matchs to a given digest. Moreover, it is also impossible to find two dissimilar messages which create an identical message digest.4.2. effectuation of SHA-1The followin g functions were implemented for the SHA-1 algorithm give ear of man-made lake shoot secure_hash_algorithm.m. business office in the ejaculate data wedge secure_hash_algorithm (message). This function takes an input a take up of characters.Example Hello, How are you? How is it going on? Output is the message digest, the hash value of the message. Thus, the hash value of the to a higher place message is F418F52AE6DC208599F91191E6C40FA876F33754. induce of solution file arithematic_ crusade_operations.m. buy the farm in the semen file arithematic_ transport_operations (number, position, op). The inputs arenumber it is a hexa ten-fold large number of any size. The number is represented in base 16 and is stored as a string. Ex FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFposition the number of positions to be shifted by. It is a quantitative number in base 10.Op it is the type of operation through with(p). Inputs are SRA - shift right arithematic and SLA - shift left arithematic.For ex ample, the functionarithematic_shift_operations(FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 3, SRA) would return 1FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, andarithematic_shift_operations(FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 3, SLA) would return FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF8.Name of source file bi2hex.m. Function in the source file bi2hex (number). The input to this function is a vector of ones and zeros and the result is a hex output represented in string. For example, for the input Number = 1 1 1 1 bi2hex (Number) returns F and for Number = 1 1 1 1 0 0 0 1 bi2hex (Number) returns F1.Name of source file hex2bi.m. Function in the source file hex2bi (number). The input to this function is a number stored in form of a string in base 16 and the result is a vector containing the binary representation of input string. For example, for the input Number = F , hex2bi (Number) returns 1 1 1 1 and for Number = F1 , bi2hex (Number) returns 1 1 1 1 0 0 0 1.Name of source file hexadecimal_big_number_adde r.m. Function in the source file hexadecimal_big_number_adder (number_one, number_two). The inputs to this function are numbers stored in hexadecimal string format. Output is the result, a hexadecimal string and give tongue to, a decimal number. After using this function, it has to be checked if the carry is generated, Incase if it is generated then the carry has to be appended in the beginning to the result. For exampleNumber_one = FFFFFFFFNumber_two = EEEEEEEEresult, carry = hexadecimal_big_number_adder (Number_one, Number_two)Result = EEEEEEED , carry = 1Hence the real sum is Result = strcat(dec2hex(0), Result) this results to 1EEEEEEEDName of source file hexadecimal_big_number_subtractor.m. Function in the source file hexadecimal_big_number_subtractor(number_one, number_two). The inputs to this function are numbers stored in hexadecimal string format. Output is the result, a hexadecimal string and sign, a decimal number. If sign is -1, then the result generated is a negative nu mber else is a positive number. . For exampleNumber_one= EEEEEEEENumber_two= FFFFFFFFresult, sign = hexadecimal_big_number_subtractor(Number_one, Number_two)Result = 11111111Sign = -1.Name of source file hexadecimal_big_number_multiprecision_multiplication.m. Function in the source file hexadecimal_big_number_multiprecision_multiplication(multiplicand, multiplier). The input is a multiplicand stored in string format is a hexadecimal number. And so is multiplier. The output is a result and is stored in form of a string. For examplemultiplicand= EEEEEEEEmultiplier= FFFFFFFFhexadecimal_big_number_multiprecision_multiplication(multiplicand, multiplier)result is EEEEEEED11111112Name of source file comparision_of.m. Function in the source file comparision_of(number_one, number_two, proponent). This function compares two numbers in hexadecimal format stored in form of strings. Always input index as decimal 1. Therefore, itReturns 1 if Number_one Number_two,Returns 0 if Number_one = Numbe r_two, andReturns -1 if Number_one For example, ifNumber_one= EEEEEEEENumber_two= FFFFFFFF, the result would becomparision_of(Number_one, Number_two, 1) returns -1.Name of source file hexadecimal_big_number_modular_exponentiation.m. Function in the source file hexadecimal_big_number_modular_exponentiation (base, exponent, modulus). This function calculates (power(base, exponent) % modulus). Here the input base, exponent and modulus are hexadecimal strings of any size. For exampleBase = FFFExponent = EEEModulus = AAAAhexadecimal_big_number_modular_exponentiation (Base, Exponent, Modulus) returns 8BABName of source file hexadecimal_big_number_ increasing_inverse.m. Function in the source file Z = hexadecimal_big_number_multiplicative_inverse(number_one, number_two). This function returns multiplicative inverse of number_two modulo number_one. If az = 1 (mod m) then z is the multiplicative inverse of a mod m. Here number_one = m, number_two = a, number_one = FFFF , number_two = 1235 a ndresult is 634D, which in turn is the multiplicative inverse of number_two.Hence (result * number_two) mod number_one = 1Name of source file hexadecimal_big_number_test_for_primality.m. Function in the source file hexadecimal_big_number_test_for_primality(number). The input to this function is an ODD number stored in hexadecimal format as a string. This function returns 1 if the input is a prime and returns -1 if input is composite.Name of source file power_of_two_conversion_to_hexadecimal.m. Function in the source file power_of_two_conversion_to_hexadecimal(power). The input is the number, the power to which two has to be raised to. It is a decimal number and the output is a hexadecimal number in form of string. For example, power_of_two_conversion_to_hexadecimal(4) returns 10 i.e 16 in decimal system.Name of source file hexadecimal_big_number_division.m. Function in the source file hexadecimal_big_number_division (dividend, divisor). This function returns quotient and remainder b oth in hexadecimal string format. The inputs to this function are strings of hexadecimal format. This function uses other two functions in turn which are defined in source file Get_multiplier.m, multiplication_by_single_digit_multiplier.m.Name of source file remove_leading_zeros.m. Function in the source file remove_leading_zeros (number). This function takes number in hexadecimal string format as input and removes the leading zeros in the string and returns it. For example, if Number = 000000012345 , then the function returns 12345.Some of the most prominent functions are presented in Appendix A.4.3. Introduction to MD5The MD5 Message- distil Algorithm is a extensively utilised in cryptographic hash functions. Basically this is the case for cryptographic hash functions with a 128-bit (16-byte) hash value. MD5 is used in many security applications, and in addition it is frequently used to check data integrity. An MD5 hash is typically expressed as a 32-digit hexadecimal number.The f ollowing figure represents a schematic view of the MD5 Message-Digest Algorithm.4.4. Implementation of MD5This algorithm would compute MD5 hash function for files. For example, if as input is given the d = md5( computer file name), then the function md5() will computes the MD5 hash function of the file specified in the string computer filename. This function will returns it as a 64-character array dwhere d is the digest. The following methodology that the MD5 algorithm was implementedInitially, the function Digestis called.This function would read the whole file, and will make it uint32 vectorFileName = Cmd5InputFile.txtMessage,nBits = readmessagefromfile(FileName)Then, it would append a bit in the last one that was read from that fileBytesInLastInt = mod(nBits,32)/8if BytesInLastIntMessage(end) = bitset(Message(end),BytesInLastInt*8+8)elseMessage = Message uint32(128)endConsequetly, it will append the zerosnZeros = 16 mod(numel(Message)+2,16)Message = Message zeros(nZeros,1,uint3 2)And a bit length of the original message as uint64, such as the lower significant uint32 firstLower32 = uint32(nBits)Upper32 = uint32(bitshift(uint64(nBits),-32))Message = Message Lower32 Upper32The 64-element transformation array isT = uint32(fix(4294967296*abs(sin(164))))The 64-element array of number of bits for beak left shiftS = repmat(7 12 17 22 5 9 14 20 4 11 16 23 6 10 15 21.,4,1)S = S().Finally, the 64-element array of indices into X can be presented asidxX = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 6 11 0 5 10 15 4 9 14 3 8 13 2 7 12 5 8 11 14 1 4 7 10 13 0 3 6 9 12 15 2 0 7 14 5 12 3 10 1 8 15 6 13 4 11 2 9 + 1The initial state of the buffer is consisting of A, B, C and D. such asA = uint32(hex2dec(67452301))B = uint32(hex2dec(efcdab89))C = uint32(hex2dec(98badcfe))D = uint32(hex2dec(10325476))The message is reshaped, such asMessage = reshape(Message,16,)The look between the blocks, such that X is an source of the next blockfor iBlock = 1size(Message,2)X = Message(,iBl ock)The buffer states are stored asAA = ABB = BCC = CDD = DThe buffer is change by utilizing the X block from above, and the parameters from S, T and idxXk = 0for iRound = 14for q = 14A = Fun(iRound,A,B,C,D,X(idxX(k+1)),S(k+1),T(k+1))D = Fun(iRound,D,A,B,C,X(idxX(k+2)),S(k+2),T(k+2))C = Fun(iRound,C,D,A,B,X(idxX(k+3)),S(k+3),T(k+3))B = Fun(iRound,B,C,D,A,X(idxX(k+4)),S(k+4),T(k+4))k = k + 4endendThe old buffer state is also being addedA = bitadd32(A,AA)B = bitadd32(B,BB)C = bitadd32(C,CC)D = bitadd32(D,DD)endThe message digest is being formed the following wayStr = lower(dec2hex(ABCD))Str = Str(,7 8 5 6 3 4 1 2).Digest = Str().The subsequent functionality is performed by the following operationsfunction y = Fun(iRound,a,b,c,d,x,s,t)switch iRoundcase 1q = bitor(bitand(b,c),bitand(bitcmp(b),d))case 2q = bitor(bitand(b,d),bitand(c,bitcmp(d)))case 3q = bitxor(bitxor(b,c),d)case 4q = bitxor(c,bitor(b,bitcmp(d)))endy = bitadd32(b,rotateleft32(bitadd32(a,q,x,t),s))And the bits are revolv e such asfunction y = rotateleft32(x,s)y = bitor(bitshift(x,s),bitshift(x,s-32))The sum function is presented asfunction sum = bitadd32(varargin)sum = varargin1for k = 2narginadd = vararginkcarry = bitand(sum,add)sum = bitxor(sum,add)for q = 132shift = bitshift(carry,1)carry = bitand(shift,sum)sum = bitxor(shift,sum)endendA message is being read frm a file, such asfunction Message,nBits = readmessagefromfile(FileName)hFile,ErrMsg = fopen(FileName,r)error(ErrMsg)Message = fread(hFile,inf,ubit32=uint32)fclose(hFile)d = dir(FileName)nBits = d.bytes*8Lastly, the auto test function is the followingfunction md5autotestdisp(Running md5 autotest)Messages1 = Messages2 = aMessages3 = abcMessages4 = message digestMessages5 = abcdefghijklmnopqrstuvwxyzMessages6 = ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789Messages7 = char(128255)CorrectDigests1 = d41d8cd98f00b204e9800998ecf8427eCorrectDigests2 = 0cc175b9c0f1b6a831c399e269772661CorrectDigests3 = 900150983cd24fb0d6963f7d28e17f7 2CorrectDigests4 = f96b697d7cb7938d525a2f31aaf161d0CorrectDigests5 = c3fcd3d76192e4007dfb496cca67e13bCorrectDigests6 = d174ab98d277d9f5a5611c2c9f419d9fCorrectDigests7 = 16f404156c0500ac48efa2d3abc5fbcfTmpFile = tempnamefor k=1numel(Messages)h,ErrMsg = fopen(TmpFile,w)error(ErrMsg)fwrite(h,Messagesk,char)fclose(h)Digest = md5(TmpFile)fprintf(%d %sn,k,Digest)if strcmp(Digest,CorrectDigestsk)error(md5 autotest failed on the following string %s,Messagesk)endenddelete(TmpFile)disp(md5 autotest passed)4.4.1 ResultsThis algorithm is tested with the input university of Portsmouth department of electronic and computer engineering. This was written on the file C//md5InputFile.txt. The outpus results are as in the following fuguresTextual description of the output results followsOUTPUTFileName = Cmd5InputFile.txt Running md5 autotest FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 1836348001 544501349 1696622191 1952671084 1768845170 1851 859043 1868767332 1953853549 1696625253 1852401518 1769104741 264781 3129b41fa9e7159c2a03ad8c161a7424FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 1836348001 544501349 1696622191 1952671084 1768845170 1851859043 1868767332 1953853549 1696625253 1852401518 1769104741 264782 3129b41fa9e7159c2a03ad8c161a7424FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 1836348001 544501349 1696622191 1952671084 1768845170 1851859043 1868767332 1953853549 1696625253 1852401518 1769104741 264783 3129b41fa9e7159c2a03ad8c161a7424FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 1836348001 544501349 1696622191 1952671084 1768845170 1851859043 1868767332 1953853549 1696625253 1852401518 1769104741 264784 3129b41fa9e7159c2a03ad8c161a7424FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 183 6348001 544501349 1696622191 1952671084 1768845170 1851859043 1868767332 1953853549 1696625253 1852401518 1769104741 264785 3129b41fa9e7159c2a03ad8c161a7424FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 1836348001 544501349 1696622191 1952671084 1768845170 1851859043 1868767332 1953853549 1696625253 1852401518 1769104741 264786 3129b41fa9e7159c2a03ad8c161a7424FileName =Cmd5InputFile.txt1986621045 1769173605 1864399220 1867522150 1836282994 1752462703 1885692960 1836348001 544501349 1696622191 1952671084 1768845170 1851859043 1868767332 1953853549 1696625253 1852401518 1769104741 264787 3129b41fa9e7159c2a03ad8c161a7424 md5 autotest passed4.5. Introduction to Caesar cipherThe Caesar cipher in cryptography, is in essence a shift cipher. It represents as one of the simplest and most widely known encryption methodologies. The Caesar cipher is a kind of substitution cipher. It means that each letter in a given plaintext is replaced by another letter. This is done due shifting by some fixed number of positions piling the alphabet. Julius Caesar was the first to use this ci