HMAC issue on Multiple files

2008-11-12
2013-04-15
  • steve newland
    steve newland
    2008-11-12

    My observations when HMAC(SHA1) is selected for multiple files:

    Only the HMAC(SHA1) Message Digest of the FIRST file is correct!

    Subsequent files show an incorrect Message Digest when compared to a known Message Digest source (e.g. HashCalc).

    See the following test results for 3 identical files:

    Test 1 no HMAC
    File;crc32;sha1
    C:\rng1.bin;C8BC3697;081B784484390550305DF369E20877756A68E06E
    C:\rng6.bin;C8BC3697;081B784484390550305DF369E20877756A68E06E
    C:\rng7.bin;C8BC3697;081B784484390550305DF369E20877756A68E06E

    Test 2 HMAC
    File;sha1
    C:\rng1.bin;90D4BD1410916BF857B977F3A6449DC558263294
    C:\rng6.bin;0D657F4DD9D05AD82DBD212B8314A0C6C752B69C
    C:\rng7.bin;0D657F4DD9D05AD82DBD212B8314A0C6C752B69C

    HashCalc:
    C:\rng1.bin - 90d4bd1410916bf857b977f3a6449dc558263294
    C:\rng6.bin - 90d4bd1410916bf857b977f3a6449dc558263294
    C:\rng7.bin - 90d4bd1410916bf857b977f3a6449dc558263294

    Also: HMAC seed is a Text String (not Hex.)

    Steve N.