What's a good method/function to create a reversible hash?

Question

I need to transmit some data over the wire and I don't want that data being plain text.

The text I'm sending needs to be reversed so I can't md5/sha256/etc...

What's a good way to encode a salted string?

Answer 1

You're looking for encryption.

What language are you using? You probably have a built-in encryption algorithm you can use.

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The idea with hashing is that you can only go one-way.

[plain text]--->(HASH ALGORITHM)--->HASH

Whereas the idea with encryption is that you can use a key together with some plaintext to create a ciphertext. Then you can use the key on the ciphertext to retrieve the plaintext at any time:

[plain text] + [key] --->(ENCRYPTION ALGORITHM)-->[ciphertext]
[ciphertext] + [key] --->(DECRYPTION ALGORITHM)-->[plain text]

The decryption algorithm for a given encryption algorithm is usually very similar to the encryption algorithm, and it allows for the retrieval of a plaintext message given a ciphertext and the correct key (ie password).

Answer 2

You want to use an encryption function, not a hash - which by definition is one-way.

The AES encryption algorithm would be a good start, as the is probably the most widely used one at present.

Answer 3

You don't want a hash, you want encryption. You should look at Blowfish.