Go

Streaming Encryption by Encrypting in Chunks

See more Encryption Examples

Encrypt data in chunks. Go

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

    crypt := chilkat.NewCrypt2()

    crypt.SetCryptAlgorithm("aes")
    crypt.SetCipherMode("cbc")
    crypt.SetKeyLength(128)

    crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex")
    crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex")

    crypt.SetEncodingMode("hex")
    txt1 := "The quick brown fox jumped over the lazy dog.\r\n"
    txt2 := "-\r\n"
    txt3 := "Done.\r\n"

    sbEncrypted := chilkat.NewStringBuilder()

    // Encrypt the 1st chunk:
    // (don't worry about feeding the data to the encryptor in 
    // exact multiples of the encryption algorithm's block size.
    // Chilkat will buffer the data.)
    crypt.SetFirstChunk(true)
    crypt.SetLastChunk(false)
    sbEncrypted.Append(*crypt.EncryptStringENC(txt1))

    // Encrypt the 2nd chunk
    crypt.SetFirstChunk(false)
    crypt.SetLastChunk(false)
    sbEncrypted.Append(*crypt.EncryptStringENC(txt2))

    // Now encrypt N more chunks...
    // Remember -- we're doing this in CBC mode, so each call
    // to the encrypt method depends on the state from previous
    // calls...
    crypt.SetFirstChunk(false)
    crypt.SetLastChunk(false)
    var i int
    for i = 0; i <= 4; i++ {
        sbEncrypted.Append(*crypt.EncryptStringENC(txt1))
        sbEncrypted.Append(*crypt.EncryptStringENC(txt2))
    }

    // Now encrypt the last chunk:
    crypt.SetFirstChunk(false)
    crypt.SetLastChunk(true)
    sbEncrypted.Append(*crypt.EncryptStringENC(txt3))

    fmt.Println(*sbEncrypted.GetAsString())

    // Now decrypt in one call.
    // (The data we're decrypting is both the first AND last chunk.)  
    crypt.SetFirstChunk(true)
    crypt.SetLastChunk(true)
    decryptedText := crypt.DecryptStringENC(*sbEncrypted.GetAsString())

    fmt.Println(*decryptedText)

    // Note: You may decrypt in N chunks by setting the FirstChunk
    // and LastChunk properties prior to calling the Decrypt* methods

    crypt.DisposeCrypt2()
    sbEncrypted.DisposeStringBuilder()