Category Archives: cryptography

Use steganography to hide one large picture inside another in C#

The example Use steganography to hide one picture inside another in C# explains how you can hide one image inside another. This example uses the same tools to hide a large image inside another large image so you can get … Continue reading

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Use steganography to hide one picture inside another in C#

The example Use steganography to hide messages in an image in C# hides message bits in the least-significant color bits of randomly selected pixels within an image. The idea is that small changes to the least significant bits of a … Continue reading

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Use steganography to hide multiple images with different sizes in C#

The post Use steganography to hide multiple images in C# shows how you can hide four images inside another another image. Unfortunately it requires that the four hidden images be exactly half the width and half the height of the … Continue reading

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Use steganography to hide multiple images in C#

The post Use steganography to hide one picture inside another in C# shows how you can hide one image inside another. This example shows one simple way to hide multiple images inside a single visible image. This program simply combines … Continue reading

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Use steganography to hide Unicode message bytes in an image in C#

The post Use steganography to hide Unicode messages in an image in C# stores the bits in a message in the least significant bits of an image’s alpha, red, green, and blue color components. The post Use steganography to hide … Continue reading

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Use steganography to hide Unicode messages in an image in C#

The post Use steganography to hide messages in an image in C# shows one technique for hiding information inside an image. That method stores bits of information in the least significant bits of selected pixels scattered around the image. That … Continue reading

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Use steganography to hide messages in an image in C#

Steganography is the science of hiding information within other information. For example, a watermark “hides” an image on a piece of paper. If you look at most paper currency at a low angle or if you hold it up to … Continue reading

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Register a program for a particular system in C#

This example demonstrates a fairly simple technique that you can use to register a program for a particular system. A determined hacker could circumvent it, but for most programs it won’t be worth the effort. The idea is simple. When … Continue reading

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Encrypt or decrypt files in C#

The following EncryptFile and DecryptFile methods encrypt or decrypt files at a very high level. // Encrypt or decrypt a file, saving the results in another file. public static void EncryptFile(string password, string in_file, string out_file) { CryptFile(password, in_file, out_file, … Continue reading

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Convert between byte arrays and hexadecimal strings in C#

This example uses extension methods to convert between byte arrays and hexadecimal strings. It adds a ToHex extension method to the byte[] type and a ToBytes extension method to the string class. To create an extension method, create a public … Continue reading

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