The Blowfish algorithm is a symmetric block cipher
that can be used as a dropin replacement for DES or IDEA. It takes
a variablelength 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, First Backup is shipped with 448bit
support 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 197bit key.
Here is a more generalized example:
The most common key lengths used by today’s web browsers are
"40bit" and "128bit." As a comparison, a 40bit
key can be "cracked" within a few hours by an average
personal computer. However, a 128bit 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 128bit key.
In the preceding example, the 128bit encryption is
not just three times stronger than 40bit encryption — it
is 309,485,009,821,345,068,724,781,056 times stronger. Performing
this same analysis on a 448bit encryption key yields an encryption
strength that is 2.1X10^{96} times stronger than a 128bit 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.
Speed Comparisons of Block Ciphers 
Algorithm 
Clock cycles
per round

# of rounds 
# of clock cycles per byte encrypted 
Notes 
Blowfish 
9 
19 
18 
Free, Not patented 
Khufu/Khafre 
5 
32 
20 
Patented by Xerox 
RC5 
12 
16 
23 
Patented by RSA Data Security 
DES 
18 
16 
45 
56bit key 
IDEA 
50 
8 
50 
Patented by AscomSystec 
TripleDES 
18 
48 


Summary
Many factors must be considered when incorporating
encryption in any “securitybased” software product
like First Backup. 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 everincreasing
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.
