how can use xor logic

[suma]

hi
i want encryption & decryption when enter password
iwant use xor to make this
how that???

please tell me

 

[Oliver Wong]

hi
i want encryption & decryption when enter password
iwant use xor to make this
how that???

Use the ^ operator. See
http://java.sun.com/docs/books/jls/third_edition/html/expressions.html#15.22.1

- Oliver

 

[Luc The Perverse]

hi
i want encryption & decryption when enter password
iwant use xor to make this
how that???

please tell me

If all you want to do is obscure something, then XOR will work just fine.

If true security is an issue then you will want to use something else,
perhaps a product you didn't write yourself.

 

[jmcgill]

hi
i want encryption & decryption when enter password
iwant use xor to make this
how that???

please tell me

Take your clear text and some randomly generated text. xor each bit of
the clear text with each bit of the random text. Never reuse that block
of randomly generated text. This simple cipher turns out to be among
the strongest forms of encryption.

The hard part is if you have to transmit that secret text to some
recipient, of course...

 

[jmcgill]

If true security is an issue then you will want to use something else,
perhaps a product you didn't write yourself.

What have you got that's cryptographically stronger than xor against a
OTP of good noise?

 

[Oliver Wong]

What have you got that's cryptographically stronger than xor against a OTP
of good noise?

It's not the technique (i.e. OTP) which leads to weakness, it's
implementing it yourself (and potentially introducing bugs) which does. A
common story is trace of the cleartext being present in a temporary file or
in the system swap file.

- Oliver

 

[Luc The Perverse]

What have you got that's cryptographically stronger than xor against a OTP
of good noise?

Ok - where do you get your noise? How do you share it?

A person that does not know how to XOR two numbers together needs more
experience before writing cryptographic software.

 

[jmcgill]

Ok - where do you get your noise? How do you share it?

I never said it would be easy.

A person that does not know how to XOR two numbers together needs more
experience before writing cryptographic software.

Based on the original post, I just figured it was some educational
exercise where the poster had little risk. If it's something more
significant than that, I'd point out that there are people with Ph.D.'s
in CS and Math working in bakeries and bookshops.

 

[Luc The Perverse]

Based on the original post, I just figured it was some educational
exercise where the poster had little risk.

A naive assumption. He could be a conspiracy theorist who believes that
all software programs have backdoors in them to allow hacking, so he will
protect himself by XORing against a passphrase represented in ASCII,
repeated.

Perhaps the appropriate question would have been what it would be used for.
But as the OP has not again posted, I am not so sure he/she is following the
thread at all.

Encoding and stenographics can be fun, but true security comes from the
Ph.D.'s as you mentioned. (Although I didn't follow your part about
bakeries.)

 

[jmcgill]

Encoding and stenographics can be fun, but true security comes from the
Ph.D.'s as you mentioned. (Although I didn't follow your part about
bakeries.)

Oh, it's just a reference to the irony of someone like the original
poster working as a software engineer, drawing a salary, while people
who would be far more qualified are lucky to be baking dinner rolls in a
cafeteria, or working as cashier in a book store. That sort of thing.
The janitor at Lincoln Center is a tenor with a high C...