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  4. What is the difference between hashing or encryption a data

What is the difference between hashing or encryption a data

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  • L Lost User

    The point is: why use the term "hash", when one means "encrypt". Particularly when most people (including laymen) know what encrypt means; but think of corned beef, "hash" browns, and eggs in the other (i.e. all "hash" to the same subject: food).

    "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

    Richard DeemingR Offline
    Richard DeemingR Offline
    Richard Deeming
    wrote on last edited by
    #13

    But that's the point: it doesn't mean "encrypt". If you encrypt something, you can get the original back. If you hash it, you can't. Just because non-techies don't know the difference, that isn't an excuse to pretend there isn't a difference. :) Some people also confuse "encrypt" and "encode", and think that Convert.ToBase64String is sufficient protection for their users' passwords. Should we just lump all three concepts together under a single term? :rolleyes:


    "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

    "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

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    • Richard DeemingR Richard Deeming

      But that's the point: it doesn't mean "encrypt". If you encrypt something, you can get the original back. If you hash it, you can't. Just because non-techies don't know the difference, that isn't an excuse to pretend there isn't a difference. :) Some people also confuse "encrypt" and "encode", and think that Convert.ToBase64String is sufficient protection for their users' passwords. Should we just lump all three concepts together under a single term? :rolleyes:


      "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

      L Offline
      L Offline
      Lost User
      wrote on last edited by
      #14

      A "fully optimized" hash is 2-way; but at that point, it has lost any performance benefits. (i.e. it's an "index"). A "non-optimized" hash (the basic purpose) can hash mulitple inputs to the same "address"; making it useless for encryption and not particularly useful for passwords depending on the size of the address space. You want to play with hashing algorithms for "password security"? Not on my watch.

      "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

      Richard DeemingR OriginalGriffO 2 Replies Last reply
      0
      • L Lost User

        A "fully optimized" hash is 2-way; but at that point, it has lost any performance benefits. (i.e. it's an "index"). A "non-optimized" hash (the basic purpose) can hash mulitple inputs to the same "address"; making it useless for encryption and not particularly useful for passwords depending on the size of the address space. You want to play with hashing algorithms for "password security"? Not on my watch.

        "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

        Richard DeemingR Offline
        Richard DeemingR Offline
        Richard Deeming
        wrote on last edited by
        #15

        Gerry Schmitz wrote:

        A "fully optimized" hash is 2-way;

        I'm starting to suspect you're using a different meaning of that word. :doh:

        Hash function - Wikipedia[^]:

        In cryptographic applications, hash functions are typically expected to be practically non-invertible, meaning that it is not realistic to reconstruct the input datum x from its hash value h(x) alone without spending great amounts of computing time (see also One-way function).

        Cryptographic hash function - Wikipedia[^]:

        it is infeasible to generate a message from its hash value except by trying all possible messages

        You want to use anything other than a cryptographic hash function for password storage? Not on my watch. ;P


        "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

        "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

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        • T Tridip Bhattacharjee

          What hashing does for which its value can not be reverse ?

          tbhattacharjee

          L Offline
          L Offline
          Lost User
          wrote on last edited by
          #16

          ..there aren't many properties or methods in global::System.Object. Each item included would be included in any derived object, and since "everything" inherits from that one class at a given point, everything has those methods. There's not many of them, yet it contains a method called "GetHashCode". Has nothing to do with encryption either, but apparently it was important enough to ensure that "everything" has that method - and I'll even hint on the fact that it has nothing to do with encrypting stuff. You're welcome :)

          Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^][](X-Clacks-Overhead: GNU Terry Pratchett)

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          • L Lost User

            A "fully optimized" hash is 2-way; but at that point, it has lost any performance benefits. (i.e. it's an "index"). A "non-optimized" hash (the basic purpose) can hash mulitple inputs to the same "address"; making it useless for encryption and not particularly useful for passwords depending on the size of the address space. You want to play with hashing algorithms for "password security"? Not on my watch.

            "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

            OriginalGriffO Offline
            OriginalGriffO Offline
            OriginalGriff
            wrote on last edited by
            #17

            Gerry Schmitz wrote:

            You want to play with hashing algorithms for "password security"? Not on my watch.

            The hashing algorithms used for passwords are considerably more secure than any encryption: SHA-512 for example generates a 512 bit hash value from the (hopefully salted) user password input. This is compared with the stored hash - so the "clear text" password is never transfered out of the authenticating system - and a match confirms the input. This gives you in theory a 1 : 1.34078079e154 chance of a collision or "false positive" assuming that the hashing algorithm gives no weight to any particular range of output values. You cannot regenerate the original input from the hashed value. Encrypted password on the other hand are seriously insecure: the decryption key has to be available to the "check the password" code and that means that it's effectively stored with the encrypted data. Please, do tell us which security systems you have implemented encryption for, so we can avoid them or ensure that we only ever use a "one-time" password (which I do anyway, no two of my logins have the same password, and I use an encrypted password store to hold them - the password to that is only ever stored in my head...)

            Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

            "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
            "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

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            • Richard DeemingR Richard Deeming

              Gerry Schmitz wrote:

              even though it makes little sense

              When it comes to storing passwords to authenticate users, using anything other than a hash makes little sense. :)

              Gerry Schmitz wrote:

              Even heard of HIDAM or HDAM databases?

              Nope, and neither has Wikipedia. Google has a bunch of links to IBM documentation, but it all looks pretty dense.


              "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

              OriginalGriffO Offline
              OriginalGriffO Offline
              OriginalGriff
              wrote on last edited by
              #18

              :thumbsup:

              Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

              "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
              "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

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              • T Tridip Bhattacharjee

                What hashing does for which its value can not be reverse ?

                tbhattacharjee

                OriginalGriffO Offline
                OriginalGriffO Offline
                OriginalGriff
                wrote on last edited by
                #19

                Most of them. Try this simple one: add each byte of the input stream together, storing the result in a byte:

                byte hash = 0;
                foreach (byte b in bytes)
                {
                hash += b;
                }

                If you feed this any two bytes, can you tell from the result exactly what two bytes you started with? If you think you can, here are some examples: 123, 42, 0, 122 What two bytes values did I start with in each case? You get one guess. There will be a significant prize if you - and you alone - get it on the first attempt.

                Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

                "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
                "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

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                • OriginalGriffO OriginalGriff

                  Gerry Schmitz wrote:

                  You want to play with hashing algorithms for "password security"? Not on my watch.

                  The hashing algorithms used for passwords are considerably more secure than any encryption: SHA-512 for example generates a 512 bit hash value from the (hopefully salted) user password input. This is compared with the stored hash - so the "clear text" password is never transfered out of the authenticating system - and a match confirms the input. This gives you in theory a 1 : 1.34078079e154 chance of a collision or "false positive" assuming that the hashing algorithm gives no weight to any particular range of output values. You cannot regenerate the original input from the hashed value. Encrypted password on the other hand are seriously insecure: the decryption key has to be available to the "check the password" code and that means that it's effectively stored with the encrypted data. Please, do tell us which security systems you have implemented encryption for, so we can avoid them or ensure that we only ever use a "one-time" password (which I do anyway, no two of my logins have the same password, and I use an encrypted password store to hold them - the password to that is only ever stored in my head...)

                  Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

                  L Offline
                  L Offline
                  Lost User
                  wrote on last edited by
                  #20

                  I use Windows Authentication. I don't presume to know more. I said there would be colissions; you want to quibble about the number.

                  "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                  Richard DeemingR 1 Reply Last reply
                  0
                  • Richard DeemingR Richard Deeming

                    Gerry Schmitz wrote:

                    A "fully optimized" hash is 2-way;

                    I'm starting to suspect you're using a different meaning of that word. :doh:

                    Hash function - Wikipedia[^]:

                    In cryptographic applications, hash functions are typically expected to be practically non-invertible, meaning that it is not realistic to reconstruct the input datum x from its hash value h(x) alone without spending great amounts of computing time (see also One-way function).

                    Cryptographic hash function - Wikipedia[^]:

                    it is infeasible to generate a message from its hash value except by trying all possible messages

                    You want to use anything other than a cryptographic hash function for password storage? Not on my watch. ;P


                    "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                    L Offline
                    L Offline
                    Lost User
                    wrote on last edited by
                    #21

                    You're confirming what I've been saying.

                    "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                    Richard DeemingR Z 2 Replies Last reply
                    0
                    • L Lost User

                      I use Windows Authentication. I don't presume to know more. I said there would be colissions; you want to quibble about the number.

                      "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                      Richard DeemingR Offline
                      Richard DeemingR Offline
                      Richard Deeming
                      wrote on last edited by
                      #22

                      And how do you think Windows stores your password? :rolleyes:

                      Passwords Technical Overview[^]:

                      For use in Windows networking, including Active Directory domains, the password is stored two different ways by default: as the LAN Manager one-way function (LM OWF) and as the NT OWF. "One-way function" is a term that denotes a one-way mathematical transformation of data. ... The most common type of one-way function in use is a cryptographic hash.

                      Although interestingly, Microsoft have added to the confusion by referring to "encryption" in the same sentence.


                      "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                      "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

                      L 1 Reply Last reply
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                      • L Lost User

                        You're confirming what I've been saying.

                        "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                        Richard DeemingR Offline
                        Richard DeemingR Offline
                        Richard Deeming
                        wrote on last edited by
                        #23

                        The only thing I'm confirming is that some people don't understand the difference between encrypting and hashing. :laugh: security - Fundamental difference between Hashing and Encryption algorithms - Stack Overflow[^]


                        "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                        "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

                        L 1 Reply Last reply
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                        • Richard DeemingR Richard Deeming

                          And how do you think Windows stores your password? :rolleyes:

                          Passwords Technical Overview[^]:

                          For use in Windows networking, including Active Directory domains, the password is stored two different ways by default: as the LAN Manager one-way function (LM OWF) and as the NT OWF. "One-way function" is a term that denotes a one-way mathematical transformation of data. ... The most common type of one-way function in use is a cryptographic hash.

                          Although interestingly, Microsoft have added to the confusion by referring to "encryption" in the same sentence.


                          "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                          L Offline
                          L Offline
                          Lost User
                          wrote on last edited by
                          #24

                          In this case, I don't care and don't need to know.

                          "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

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                          • Richard DeemingR Richard Deeming

                            The only thing I'm confirming is that some people don't understand the difference between encrypting and hashing. :laugh: security - Fundamental difference between Hashing and Encryption algorithms - Stack Overflow[^]


                            "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                            L Offline
                            L Offline
                            Lost User
                            wrote on last edited by
                            #25

                            Quote:

                            A hash function is any function that can be used to map data of arbitrary size to data of fixed size

                            I also prefer "Coke Classic".

                            "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

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                            • P Pete OHanlon

                              As usual, you come here having done no research for yourself. Use Google or Bing. This information is all available for you.

                              This space for rent

                              A Offline
                              A Offline
                              Afzaal Ahmad Zeeshan
                              wrote on last edited by
                              #26

                              Not his first time. :laugh:

                              The shit I complain about It's like there ain't a cloud in the sky and it's raining out - Eminem ~! Firewall !~

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                              • L Lost User

                                You're confirming what I've been saying.

                                "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                                Z Offline
                                Z Offline
                                ZurdoDev
                                wrote on last edited by
                                #27

                                I'm with Richard. It does not appear that you are using the same understanding that others have.

                                There are two kinds of people in the world: those who can extrapolate from incomplete data. There are only 10 types of people in the world, those who understand binary and those who don't.

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                                • Z ZurdoDev

                                  I'm with Richard. It does not appear that you are using the same understanding that others have.

                                  There are two kinds of people in the world: those who can extrapolate from incomplete data. There are only 10 types of people in the world, those who understand binary and those who don't.

                                  L Offline
                                  L Offline
                                  Lost User
                                  wrote on last edited by
                                  #28

                                  You (speaking rhetorically) fixate on one technique / application and categorize a whole branch. Hashing as a technique "in" an "encryption situation"; it is only a footnote in applied cryptology ... usually with a sidebar to the effect of " ... but one only had to alter the last bit to etc. ...". If you really want to educate yourself on hashing, learn about the various ways to defeat hashing. I just thought the original question made about as much sense as asking what is the difference between a BMW and "an automobile" (which is confirmed by the length of the thread).

                                  "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                                  Richard DeemingR 1 Reply Last reply
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                                  • A Afzaal Ahmad Zeeshan

                                    Not his first time. :laugh:

                                    The shit I complain about It's like there ain't a cloud in the sky and it's raining out - Eminem ~! Firewall !~

                                    P Offline
                                    P Offline
                                    Pete OHanlon
                                    wrote on last edited by
                                    #29

                                    Indeed. I've lost count of the number of posts like this from him.

                                    This space for rent

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                                    • L Lost User

                                      You (speaking rhetorically) fixate on one technique / application and categorize a whole branch. Hashing as a technique "in" an "encryption situation"; it is only a footnote in applied cryptology ... usually with a sidebar to the effect of " ... but one only had to alter the last bit to etc. ...". If you really want to educate yourself on hashing, learn about the various ways to defeat hashing. I just thought the original question made about as much sense as asking what is the difference between a BMW and "an automobile" (which is confirmed by the length of the thread).

                                      "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

                                      Richard DeemingR Offline
                                      Richard DeemingR Offline
                                      Richard Deeming
                                      wrote on last edited by
                                      #30

                                      In general terms, yes, "hashing" has a wider meaning than "a cryptographic hash function". In the context of the original question, I think it's reasonable to assume that the OP was referring to "a cryptographic hash function", and not any of the other possible meanings. But given the OP's history as a help vampire, and the fact that he could have answered his own question by spending five minutes in Google, I also think it's reasonable to ignore the question, or direct him to Google. :)


                                      "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                                      "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

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                                      • Richard DeemingR Richard Deeming

                                        In general terms, yes, "hashing" has a wider meaning than "a cryptographic hash function". In the context of the original question, I think it's reasonable to assume that the OP was referring to "a cryptographic hash function", and not any of the other possible meanings. But given the OP's history as a help vampire, and the fact that he could have answered his own question by spending five minutes in Google, I also think it's reasonable to ignore the question, or direct him to Google. :)


                                        "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                                        L Offline
                                        L Offline
                                        Lost User
                                        wrote on last edited by
                                        #31

                                        My point is always to get the "OP" to clarify their OWN question. The fact that everyone needs to jump in an "reinterpret" my intentions is their problem. The fact that I am not always "obvious" about it, is also not my problem.

                                        "(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

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                                        • T Tridip Bhattacharjee
                                          1. please some one tell me difference between hashing or encryption a data. 2) i saw hashing also encrypt data which is not human readable and encryption does the same then why people think hashing is different from encryption ? 3) what hashing does ? 4) if we encrypt data then we can decrypt it too but if we hashing the data then can we reverse the process ? 5) if no then what algorithm hashing use that no one can reverse the data ? 6) give me two sample code to has data one will hash data without salt key and another one hash data with salt key. thanks

                                          tbhattacharjee

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                                          Patrice T
                                          wrote on last edited by
                                          #32

                                          Never thought about using Google for such basic researches ?

                                          Patrice “Everything should be made as simple as possible, but no simpler.” Albert Einstein

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