How can I apply hash on a string.

Question

Balkar Singh 2020-4-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/518881-how-can-i-apply-hash-on-a-string

评论： Balkar Singh 2020-4-20

采纳的回答： Ameer Hamza

How can i apply hash function on a string and reverse process to generate the same string from the hash value.

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Answer 1

Ameer Hamza 2020-4-18

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/518881-how-can-i-apply-hash-on-a-string#answer_426783

在 MATLAB Online 中打开

Hashing is not a reversible process. You can do encoding and decoding. For example

A = 'The quick brown fox jumps over the lazy dog';
encoded_str = matlab.net.base64encode(A);
decoded_str = char(matlab.net.base64decode(encoded_str));

Result

>> encoded_str
encoded_str =
    'VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZw=='
>> decoded_str
decoded_str =
    'The quick brown fox jumps over the lazy dog'

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Balkar Singh 2020-4-20

在 MATLAB Online 中打开

Thanks sir

s3 = containers.Map({'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9',' ','!'},{'110000','110001','110010','110011','110100','110101','110110','110111','111000','111001','111010','111011','111100','111101','111110','111111','000000','000001','000010','000011','000100','000101','000110','000111','001000','001001','010000','010001','010010','010011','010100','010101','010110','010111','011000','011001','011010','011011','011100','011101','011110','011111','100000','100001','100010','100011','100100','100101','100110','100111','101000','101001','001011','001100','001101','001110','001111','101010','101011','101100','101101','101110','101111'});

When i compare the encoded_str with this container.I got the following error

Error using containers.Map/subsref

Specified key type does not match the type expected for this container.

what is the solution of this problem.

Balkar Singh 2020-4-20

在 MATLAB Online 中打开

s3 = containers.Map({'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','','!','0'},{'110000','110001','110010','110011','110100','110101','110110','110111','111000','111001','111010','111011','111100','111101','111110','111111','000000','000001','000010','000011','000100','000101','000110','000111','001000','001001','010000','010001','010010','010011','010100','010101','010110','010111','011000','011001','011010','011011','011100','011101','011110','011111','100000','100001','100010','100011','100100','100101','100110','100111','101000','101001','001011','001100','001101','001110','001111','101010','101011','101100','101101','101110','101111','001010'});
encoded_str=mlreportgen.utils.hash(cover_str);
i=1;
cnt = length(encoded_str);
HBS='';
while(cnt>0)
     encoded_str(1,i)
     val=s3(encoded_str(1,i))  Error occured here
     i=i+1
     cnt = cnt-1;   
     %input("Hello")
     HBS=strcat(HBS,val);
end

Error using containers.Map/subsref

The specified key is not present in this container.

Ameer Hamza 2020-4-20

在 MATLAB Online 中打开

Balkar, mlreportgen.utils.hash returns a string, which is different from char array in MATLAB. length(encoded_str) returns 1 always. Change it to char array by changing the line

encoded_str=mlreportgen.utils.hash(cover_str);

to

encoded_str=char(mlreportgen.utils.hash(cover_str));

Balkar Singh 2020-4-20