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Hi Porculus - apologies for replying to such an old thread...

A few years I invented a home-grown encryption for a application I wrote, and used a scheme like you describe. Following your comment, I am concerned about the security of my encryption (which is still in use).

I am XOR'ing the plaintext against a shared secret "random" key, where the key is approx 50 thousand bytes (compared to a typical plaintext length of 10-500 bytes). The XOR starting position within the key is "random" for each encryption/call (and is then embedded within the encrypted data so the decryption algorithm can find it). The encryption program code and plaintexts are guaranteed to be private, and only the encrypted data is ever made public.

Can you briefly explain to me how an attacker would break this?

Many thanks for your help.

In reply to Re^2: Encryption using perl core functions only by ad1mt
in thread Encryption using perl core functions only by redhotpenguin

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