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Encryption - Blowfish
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The Blowfish algorithm is a symmetric block cipher that can be used as a drop-in replacement for DES or IDEA. It takes a variable-length key, from 32 bits to 448 bits, making it ideal for both domestic and exportable use.
Blowfish is classified as public domain; as such it has been analyzed extensively and gone through years of peer review. At no point since it's initial release in 1993 has the Blowfish code ever been cracked. This is significant when you consider that the source code to the algorithm is freely available.
Blowfish supports key lengths of 32 to 448 bits, making it one of the strongest encryption algorithms on the market. Since the US government (NSA) has eliminated export restrictions on encryption, DataBak is shipped with 448-bit support as standard.
Strength
The relative strength of the encryption algorithm is based on key length. Bruce Schneier, creator of the Blowfish encryption algorithm, has calculated that according to what we know of quantum mechanics today, that the entire energy output of the sun is insufficient to break a 197-bit key.
Here is a more generalized example:
The most common key lengths used by today’s web browsers are "40-bit" and "128-bit." As a comparison, a 40-bit key can be "cracked" within a few hours by an average personal computer. However, a 128-bit key would take one BILLION powerful computers, each capable of trying one BILLION keys per second. In other words, it would take MILLIONS of years to try every possible combination of bits in a 128-bit key.
In the preceding example, the 128-bit encryption is not just three times stronger than 40-bit encryption — it is 309,485,009,821,345,068,724,781,056 times stronger. Performing this same analysis on a 448-bit encryption key yields an encryption strength that is 2.1X1096 times stronger than a 128-bit key.
Speed
The speed of the algorithm is also impressive. Some may think a 448 bit key length is excessive. However, when we analyze the effective throughput of the Blowfish algorithm, we see that even large key lengths result in much faster performance than other encryption algorithms.
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Speed Comparisons of Block Ciphers
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Algorithm
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Clock cycles
per round
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# of rounds
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# of clock cycles per byte encrypted
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Notes
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Blowfish
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9
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19
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18
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Free, Not patented
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Khufu/Khafre
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5
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32
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20
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Patented by Xerox
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RC5
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12
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16
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23
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Patented by RSA Data Security
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DES
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18
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16
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45
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56-bit key
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IDEA
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50
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8
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50
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Patented by Ascom-Systec
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Triple-DES
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18
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48
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Summary
Many factors must be considered when incorporating encryption in any “security-based” software product. Encryption speed, key strength and extensive peer review of the algorithm were the key motivating factors behind the decision to utilize Blowfish encryption.
As encryption algorithms evolve to meet the ever-increasing speed of systems designed to “crack” them, we will strive to incorporate these enhanced algorithms in all of our products. But until the next generation of encryption is developed, rest assured that Blowfish will offer substantial security for many years to come and will continue to be the preferred encryption algorithm used by many corporations and banking institutions worldwide.
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