Re: File Handling in Ada -95.- Demonstartion.



On Jun 15, 11:12 am, Mok-Kong Shen <mok-kong.s...@xxxxxxxxxxx> wrote:
adacrypt worte:

......  - makes a copy file of an
existing external file - the application to cryptography is obvious. –

I don't understand this at all. Could you elaborate on your point?

M. K. Shen

This is about a rather tricky operation in programming that arises
repeatedly in cryptography in every cipher computer program.

The author of the book is not into cryptography in any way - the
example in the book reads in an existing file of plaintext ostensibly
for the puropose of copying it and outputting it as a copy-file of the
original - the object of the example is to introduce the reader to the
procedure of naming and calling external files from within a program -
(remember this is a pedagocically orientated syle of text book ) - the
example may seem trivial i.e. copying a file should be easy by a
number of other methods but that is not what is on the radar. The
objective is in file handling of files of plaintext and ciphertext.

The suggestion by me is that the same example is useful to crypto
students in that an adaptation to cryptography is obvious i.e. read in
the character of plaintext for encryption (from a prepared batch
file) , encipher it and then output it to a growing file of
ciphertext, Each character is dealt with one by one in a program
loop..

File handling i.e. reading in from and writing out to external files
is one of the more difficult operations in programming and there is
evidence that some crypto users are skirting it by reading in binary
directly from the key board which is not a professional solution or
indeed a very reliable and efficient one (error prone ) whatever they
may say in its defence - Regards - adacrypt
.



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