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<H2><A NAME="SECTION00073000000000000000">
Crypto.Util.RFC1751</A>
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The keys for private-key algorithms should be arbitrary binary data.
Many systems err by asking the user to enter a password, and then
using the password as the key. This limits the space of possible
keys, as each key byte is constrained within the range of possible
ASCII characters, 32-127, instead of the whole 0-255 range possible
with ASCII. Unfortunately, it's difficult for humans to remember 16
or 32 hex digits.
<P>
One solution is to request a lengthy passphrase from the user, and
then run it through a hash function such as SHA or MD5. Another
solution is discussed in RFC 1751, "A Convention for Human-Readable
128-bit Keys", by Daniel L. McDonald. Binary keys are transformed
into a list of short English words that should be easier to remember.
For example, the hex key EB33F77EE73D4053 is transformed to "TIDE ITCH
SLOW REIN RULE MOT".
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51#51
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52#52
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