MEDIAIMAGER – Users’ Guide, Version 1.7
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Definitions
The table below contains a list of concepts used throughout this document and their explanation.
Encryption algorithm
Commonly used in Information Technologies algorithms providing data
encryption in order to increase security. Based on complex mathematical
hashing functions. For every data set they calculate shorter signatures
which can guarantee and verify whether or not the data and its copies
are intact and unchanged.
Hashing
Process of verification which, as a result, provides checksums. Allows to
test data for any infringement.
Checksums
Result of hashing algorithm. Depending on the algorithm, it can provide
128-bit or longer string, containing alphanumeric characters, calculated
using hashing functions. Using those it’s possible to verify data in a short
period of time. The size of data being hashed doesn’t matter.
MD5
Message-Digest algorithm 5 – cryptography algorithm. A very popular
hashing function which generates 128-bit long checksums.
SHA1
Secure Hash Algorithm –a popular hashing function designed by the NSA
(U.S. National Security Agency). For any dataset, not bigger than 264 bits,
a 160-bits long checksum is generated.
SHA256
Newer, more complex hashing algorithm from Secure Hash Algorithms
family. Guarantees higher level of security using 256-bits long
checksums.
SHA384
Another version of hashing function. Results of this algorithm are 384-
bits long checksums.
SHA512
More complex, time-consuming function provide the best and most
reliable data verifications mechanisms. It generates 512-bits long
checksums which are impossible to forge or falsify.
Binary copy
Unlike the normal data copying process known to every computer user, a
binary copy is an exact copy of everything stored on the external device
(raw data). Every information, partitions, file system, attributes and
metadata is being copied.
.dd format
File extension. Contains raw data. They are full and complete data
images.
.e01 / .ex01 format
File extension. First introduced by EnCase software. Besides raw data it
contains additional information regarding hashing, data owner, case
name, case examiner etc. Most commonly used in computer forensics.
