(Swift 2) Duplicate SQL Server ENCRYPTBYPASSPHRASE

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Demonstrates how to duplicate SQL Server's ENCRYPTBYPASSPHRASE.

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func chilkatTest() {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // For SQL Server 2008 - SQL Server 2016 we must use TripleDES with SHA1
    // For SQL Server 2017 and later, use AES256 / SHA256.

    var password: String? = "tEst1234"
    var encryptedHex_v1: String? = "0x010000001E8E7DCDBD4061B951999E25D18445D2305474D2D71EEE98A241C755246F58AB"

    // Here's an encrypted string using AES256/SHA256
    var encryptedHex_v2: String? = "0x02000000FFE880C0354780481E64EF25B6197A02E2A854A4BA9D8D9BDDFDAB27EB56537ABDA0B1D9C4D1050C91B313550DECF429"

    let sbEncHex = CkoStringBuilder()
    sbEncHex.Append(encryptedHex_v1)

    // If present, we don't want the leading "0x"
    if sbEncHex.StartsWith("0x", caseSensitive: false) == true {
        sbEncHex.RemoveCharsAt(0, numChars: 2)
    }

    let crypt = CkoCrypt2()
    crypt.EncodingMode = "hex"

    // The encrypted hex string will begin with either 01000000 or 02000000
    // version 1 is produced by SQL Server 2008 to SQL Server 2016, and we must use TripleDES with SHA1
    // version 2 is for SQL Server 2017 and later, and uses AES256 / SHA256.
    var v1: Bool = sbEncHex.StartsWith("01", caseSensitive: false)

    var ivLen: Int = 0
    var hashAlg: String?

    if v1 == true {
        crypt.CryptAlgorithm = "3des"
        crypt.CipherMode = "cbc"
        crypt.KeyLength = 168
        ivLen = 8
        hashAlg = "sha1"
    }
    else {
        crypt.CryptAlgorithm = "aes"
        crypt.CipherMode = "cbc"
        crypt.KeyLength = 256
        ivLen = 16
        hashAlg = "sha256"
    }

    // Remove the SQL Server version info (i.e. the "01000000")
    sbEncHex.RemoveCharsAt(0, numChars: 8)

    // Get the IV part of the sbEncHex, and also remove it from the StringBuilder.
    var ivHex: String? = sbEncHex.GetRange(0, numChars: ivLen * 2, removeFlag: true)
    print("IV = \(ivHex!)")
    crypt.SetEncodedIV(ivHex, encoding: "hex")

    let sbPassword = CkoStringBuilder()
    sbPassword.Append(password)
    var pwd_hash: String? = sbPassword.GetHash(hashAlg, encoding: "hex", charset: "utf-16")
    let sbKey = CkoStringBuilder()
    sbKey.Append(pwd_hash)
    if v1 == true {
        // For v1, we only want the 1st 16 bytes of the 20 byte hash.
        // (remember, the hex encoding uses 2 chars per byte, so we remove the last 8 chars)
        sbKey.Shorten(8)
    }

    print("crypt key: \(sbKey.GetAsString())")

    crypt.SetEncodedKey(sbKey.GetAsString(), encoding: "hex")

    // Decrypt
    let bd = CkoBinData()
    bd.AppendEncoded(sbEncHex.GetAsString(), encoding: "hex")
    crypt.DecryptBd(bd)

    // The result is composed of a header of 8 bytes which we can discard.
    // The remainder is the decrypted text.

    // The header we are discarding is composed of:
    // Bytes 0-3: Magic number equal to 0DF0ADBA
    // Bytes 4-5: Number of integrity bytes, which is 0 unless an authenticator is used. We're assuming no authenticator is used.
    // Bytes 6-7: Number of plain-text bytes. We really don't need this because the CBC padding takes care of it.

    // Therefore, just return the data after the 1st 8 bytes.
    // Assuming the encrypted string was utf-8 text...
    bd.RemoveChunk(0, numBytes: 8)
    var plainText: String? = bd.GetString("utf-8")
    print("decrypted plain text: \(plainText!)")

    // The output:

    // IV = 1E8E7DCDBD4061B9
    // crypt key: 710B9C2E61ACCC9570D4112203BD9738
    // decrypted plain text: Hello world.

    // ------------------------------------------------------------------------------------------
    // To encrypt, do the reverse...

    // Let's do v1 with TripleDES with SHA1

    let encryptor = CkoCrypt2()
    encryptor.EncodingMode = "hex"

    encryptor.CryptAlgorithm = "3des"
    encryptor.CipherMode = "cbc"
    encryptor.KeyLength = 168

    // Generate a random 8-byte IV
    let prng = CkoPrng()
    ivHex = prng.GenRandom(8, encoding: "hex")
    encryptor.SetEncodedIV(ivHex, encoding: "hex")

    // The binary password is generated the same as above.
    // We'll use the same password (and same binary password)
    encryptor.SetEncodedKey(sbKey.GetAsString(), encoding: "hex")

    var plainTextLen: Int = 8
    plainText = "ABCD1234"

    // Encrypt the header + the plain-text.
    let bdData = CkoBinData()
    bdData.AppendEncoded("0DF0ADBA", encoding: "hex")
    bdData.AppendEncoded("0000", encoding: "hex")
    bdData.AppendInt2(plainTextLen, littleEndian: true)
    print("header: \(bdData.GetEncoded("hex"))")
    bdData.AppendString(plainText, charset: "utf-8")
    encryptor.EncryptBd(bdData)

    // Compose the result..
    let sbEnc = CkoStringBuilder()
    sbEnc.Append("0x01000000")
    sbEnc.Append(ivHex)
    sbEnc.Append(bdData.GetEncoded("hex"))

    print("result: \(sbEnc.GetAsString())")

}