(Go) RSA Encrypt and Decrypt Credit Card Numbers

Go sample code to RSA public-key encrypt and decrypt credit card numbers. The RSA key is loaded from an unencrypted PKCS8 file. Chilkat provides many ways of setting the key -- loading from both encrypted and unencrypted PEM, PKCS8, DER, PVK, etc. Keys may be loaded from files or in-memory representations. (The RSA component also provides the ability to generate RSA keys.)

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    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    rsa := chilkat.NewRsa()

    key := chilkat.NewPrivateKey()

    // Load an RSA private key from a file:
    success := key.LoadAnyFormatFile("rsaPrivateKey.key","")
    if success != true {
        fmt.Println(key.LastErrorText())
        rsa.DisposeRsa()
        key.DisposePrivateKey()
        return
    }

    // Get the key as XML:
    var keyXml *string = new(string)
    keyXml = *key.GetXml()

    // We'll encrypt with the public key and decrypt with the private
    // key.  (It's also possible to do the reverse.)
    // Note: An RSA private key is composed of different parts internally: modulus, exponent, P, Q, etc.
    // An RSA public-key is a sub-set of the private key.
    // Therefore, when you have a private key, you really have
    // both public and private keys.
    success = rsa.ImportPublicKey(*keyXml)
    if success != true {
        fmt.Println(rsa.LastErrorText())
        rsa.DisposeRsa()
        key.DisposePrivateKey()
        return
    }

    // Encrypt a VISA credit card number:
    // 1234-5678-0000-9999
    ccNumber := "1234567800009999"

    usePrivateKey := false
    rsa.SetEncodingMode("base64")
    encryptedStr := rsa.EncryptStringENC(ccNumber,usePrivateKey)
    fmt.Println("Encrypted:")
    fmt.Println(*encryptedStr)

    // Now decrypt:
    rsaDecryptor := chilkat.NewRsa()

    rsaDecryptor.SetEncodingMode("base64")
    success = rsaDecryptor.ImportPrivateKey(*keyXml)

    usePrivateKey = true
    decryptedStr := rsaDecryptor.DecryptStringENC(*encryptedStr,usePrivateKey)

    fmt.Println("Decrypted:")
    fmt.Println(*decryptedStr)

    // Important: RSA encryption should only be used to encrypt small amounts of data.
    // It is typically used for encrypting symmetric encryption
    // keys such that a symmetric encryption algorithm, such as 
    // AES is then used to encrypt/decrypt bulk data

    rsa.DisposeRsa()
    key.DisposePrivateKey()
    rsaDecryptor.DisposeRsa()