Encryption/Decryption classes

I need a class to encrypt and decrypt strings. There will need to be TWO VERSIONS of the class, one for Visual C++ and the other written for LotusScript. LotusScript is a Lotus Note scripting language which is very similar to Visual Basic 6. You can download the LotusScript language reference here:

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Note that I DO NOT want .NET code. The code must work the same in the C++ class as it does in the LotusScript class. A string that has been encrypted with one version can be decrypted in the other, and vice-versa.

I am open to suggestions on the encryption method to use but Triple DES is preferred unless you can convince me of a better option. I need a good level security but not the absolute best, so public/private key is probably overkill.

When the class encrypts the string it must then convert the string to hex. When the class decrypts the string it must first “de-hex” the string before decrypting. These strings are converted to/from hex because Triple-Des can return some ascii chars which cause problems when reading and writing to files.

The class also has to be able to read/write the string to/from a file.

Class Methods

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SetFilename ()

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Parameter: Filename (string)

Returns: n/a

Sets the filename to be read from or written to.

GetFilename ()

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Parameter: n/a

Returns: Filename (string)

Returns the name of the filename to be read from or written to.

SetKey()

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Parameter: Key (string)

Returns: n/a

Sets the encryption key.

GetKey()

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Parameter: n/a

Returns: Key (string)

Returns the encryption key.

SetData()

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Parameter: Data (string)

Returns: n/a

Sets the data string.

GetData()

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Parameter: n/a

Returns: Data (string)

Returns the data string.

Encrypt()

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Parameter: n/a

Returns: True/False if encrypted ok.

1. Encrypts the data string with the key.

2. Converts the encrypted string to hex.

Decrypt()

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Parameter: n/a

Returns: True/False if decrypted ok.

1. Converts the encrypted string from hex (de-hex the string).

2. Decrypts the data string with the key.

SetEncryptedString()

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Parameter: Encrypted Data (string)

Returns: n/a

Sets the encrypted (and hexed) data string..

GetEncryptedString ()

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Parameter: n/a

Returns: Encrypted Data (string)

Returns the encrypted (and hexed) data string.

WriteString()

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Parameter: n/a

Returns: True/False if written ok.

Writes the encrypted (and hexed) string to the file.

ReadString ()

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Parameter: n/a

Returns: True/False if read ok.

1. Converts the encrypted string to hex.

2. Decrypts the data string with the key.

I haven’t specified the member variables for the class. These should be fairly obvious. If they aren’t obvious then you may not be the right person for the job.

If you can see a better way of doing this then let me know. Maybe separate Encrypt class and Decrypt class.

Payments

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I will not be making any advanced payments. Payment will be made using escrow.

Future Work

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I have a lot more projects coming soon. I would like to work with the same people on future projects.

What I need from you

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1. Indicate that you can provide classes for both VC++ and LotusScript

2. Tell me about similar projects you’ve worked on.

3. Give me your best FIXED price bid.

Let me know if you have any questions.

(This same information is in the attached Word document)

UPDATE
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There are two classes required. One class for C++. One class for LotusScript. The Lotusscript code must be native LotusScript - no DLL calls. Make sure you understand this.

The C++ code will run on Windows but CANNOT use the Microsoft Crypto API. The encryption and decryption classes must be native in the code.

C Programming Visual Basic

Project ID: #151883

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