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| Embedded Controller |
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| In hard disk drives, a controller built into the same physical unit that houses the hard disk drive rather than a separate adapter card. IDE and SCSI drives both use these |
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| Encryption (Thou shalt use encryption for sensitive data) |
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Encryption or cryptography (Latin crypt meaning secret and graphia meaning writing; Greek kryptós meaning hidden and lógos meaning word) is the technology and science of storing information (encoding data) in a form that prevents any unauthorised party from reading (to render it unintelligible) or changing it. Cryptography deals with very human concerns, issues of privacy, authenticity, and trust, but it does so in a way that is concrete and mathematical.
If an unauthorised party views the information using a hex editor, this person only sees sequences of garbled characters or gobbledegook and symbols. A cryptographic algorithm (also referred to as a routine or method) determines the level of protection provided by encryption. Today the scientific discipline, as old as human civilisation, is now part of statecraft, diplomacy, war, government strategy and commercial transactions.
Strong encryption was previously only military business; however, in the information society in which we live today, it has become one of the central tools for maintaining privacy and confidentiality.
Genie Backup Manager’s (GBM) implementation of encryption security had two main objectives in mind: ease-of-use and top security (utilising the extensively-studied and widely-used block-cipher AES FIPS approved encryption algorithms (Rijndael algorithm) encryption). This is important in protecting sensitive documents using a 128-, 192- or 256-bit encryption key. This cipher can be used very efficiently in software and hardware for it robustness and stability.
The recent 64-bit ZIP archive cipher uses the cryptographic hash function HMAC (Hash Message Authentication Codes)-SHA (Secure Hash Algorithm)-1; HMAC-SHA-1), takes a message of length less than 2^64, producing a 160-bit hash value (a standard recently) from an arbitrary length string, as a result, mixing the outputs in a complicated way to produce a 128-, 192- or 256-bit encryption key. Note: 128-, 192- and 256-bit numbers refer to the size of the encryption keys that are used to encrypt the archive. Cryptographic hash functions play a fundamental role in modern cryptography. The bit length of the cipher used to encrypt an archive helps to determine the overall security of the archive. The longer the bit length, the harder it should be for an unauthorised party to decrypt the contents because the number of possible keys dictates the number of possible encryptions. Generally, the longer the encryption bit length, the harder it is to decrypt the contents of the archive.
A practical motivation for constructing hash functions from block ciphers is that if an efficient implementation of a block cipher is already available within a system (either in hardware or software), then using it as the central component for a hash function may provide the latter functionality at little additional cost. The (not always well-founded) hope is that a good block cipher may serve as a building block for the creation of a hash function with properties suitable for various applications.
Data security does not only depend on the strength of the encryption method but also on the strength of the password e.g., length and composition of the password. If a ZIP, or RAR for that matter, archive password's complexity and length contains a mixture of letters (upper and lower case), digits, punctuation, spaces, and symbols, this increases password recovery time exponentially. In other words, relatively minor adjustments in password character length and complexity will have a massive effect on security. Generally, the longer the password character length (complexity included), the harder it is to gain unauthorised access to the contents of the archive. In fact, taking full advantage of the full strength of AES (a block cipher with 128-bit block size and 128- or 256-bit keys, for example) encryption requires a password approximately 32 characters for 128-bit encryption and 64 characters for 256-bit encryption. For increased security, change your passphrase every 30 to 90 days. Please note that unlike the RAR encrypted archives, ZIP encryption archives apply to the contents of files stored within it only. Information about an encrypted file, e.g., name, date, size, attributes, and compression ratio, are stored in unencrypted form in the ZIP file's directory. This information can be viewed, without a password, by anyone who has access to the ZIP file.
However, 64-bit ZIP protected archives can take advantage of AES 256-bit encryption that has the highest probability of success against password retrieval programs using brute-force. This also means that valuable data will be lost indefinitely if the password is forgotten etc.
Passphrase creation:
- Use a passphrase that is easy to remember but hard to guess. Do not write it down.
- The passphrase should contain a combination of a minimum of eight characters long.
- Do not use names, numbers or words that are related to you in any way or that can be found from dictionaries.
- Never disclose your passphrase to anybody and change it regularly. (For increased security, change your passphrase every 30 to 90 days).
A passphrase can be a short sentence you can easily remember, or a traditional password with random letters, numbers, and punctuation. You can, for example, choose a long sentence and use the first letter of the each word in that sentence as your passphrase.
Side note: In order for a computer program to encrypt it requires a key using generated numbers. A key is simply a series of numbers. Ideally, the program needs to be able to acquire each number randomly. If a sample of values using this tool (random number generator or RNG) can generate sequences of numbers which have various properties of randomness that can succeed against the entire pattern determining tests, then it can be regarded as an appropriate number for a key and the tool can be regarded as robust and “look” random. Nevertheless, a pseudo-random number is reproducible with a modicum of cryptanalytic expertise and masses of computer power. Suffice it to say, a PRNG number cannot be regarded as random (it can stretch a little bit of randomness into a lot of pseudo-randomness) but it will past all the test of randomness – hence the name pseudo-random. Nevertheless, this is another core problem of cryptography as deterministic machines, such as a computer, cannot generate randomness only pseudo-randomness so there can not be any guarantee that the random bit sequence will be free of biases and correlations, as this is a difficult task.
Even so, it is certainly better that nothing and will deter the casual cracker.
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| Environment Variable |
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Windows can use a string consisting of environment information – such as a drive, path, or filename – associated with a symbolic name. Through the Control Panel, use the Systems applet or the set command from the command prompt to define environment variables. It is important to be careful when changing the expandable portion of the data type of an expandable string so that it matches the environmental variables or the value will cease to function correctly. Environment variables are used in Windows to allow scripts, registry entries and other applications to use wildcards for important system information that may change. The GUI route is Control Panel>System applet>Advanced Tab or via the registry HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment subkey.
See: Variable, and Windows Registry. |
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| Exabyte (a million terabytes, symbol EB) |
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| One billion billion bytes |
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| Extended Partition |
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A special type of partition (partition type) of which there can be only one – but non-bootable DOS partition - that is created on a basic master boot record (MBR), but it also contains its own MBR and partition table ((legacy)-style partition table entry type 05 and 0F hex). Extended partitions are useful, because it is possible to create more than four volumes on the basic MBR disk - it allocates an area in which the equivalent of a primary partition ((legacy)-style partition table entry type 42 or 0x42) in an extended partition is called alogical dos drive can be located. Unlike primary partitions, an extended partition is not formatted with a filesystem and then assigned a drive letter. Instead, one or more logical dos drives are created within the extended partition. The logical dos drive can then be formatted and assigned a drive letter. Only one of the four partitions allowed per hard disk drive can be an extended partition, and no primary partition needs to be present to create an extended partition. Extended partitions can only be created on basic disks. The first sector, and the most important sector contains the descriptor of the extended partition containing a partition table that defines the first logical partition (in entry 1) and, if multiple logical drives are present, a pointer to the next partition table (in entry 2). This first sector of the extended partition is called the EPBR (Extended Partition Boot Record).
Starting with DOS 3.3, the FDISK program can create two partitions that serve DOS: an ordinary, bootable partition (called the primary partition) and an extended partition. The recursion that extended partitions permit can continue indefinitely, which means that no upper limit exists to the number of possible partitions on a hard disk drive. This overcomes Microsoft’s operating system limit apportioning scheme of four partitions. In other words, extended partitions can contain extended partitions, which can contain extended partitions and so on, making the number of volumes a Microsoft operating system can place on a hard disk drive effectively infinite.
For an extended partition it is represented within the partition table of the MBR as type 07.
See: Extended Partition Boot Record (EPBR), MBR Disk, Master Boot Record (MBR), Partition, and Partition Table. |
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| Extended Partition Boot Record (EPBR) |
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The location varies and depends on the locations of logical partitions but it is the first sector of the extended partition. The first sector of the extended partition contains a partition table that defines the first logical partition (in entry 1) and, if multiple logical drives are present, a pointer to the next partition table (in entry 2) and so on until the chain ends.
The EPBR can also contain four partition table entries.
See: Extended Partition, MBR Disk, Master Boot Record (MBR), Partition, and Partition Table. |
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