Unprotected content length for decryption ?

[puthurr]

Hi All,

The DecryptBuffer method on the protection handler expects the following parameters

• offsetFromStart: Relative position of inputBuffer from the very beginning of the encrypted content
• inputBuffer: Buffer of encrypted content that will be decrypted
• inputBufferSize: Size (in bytes) of input buffer
• outputBuffer: Buffer into which decrypted content will be copied
• outputBufferSize: Size (in bytes) of output buffer
• isFinal: If input buffer contains the final encrypted bytes or not

=> Returns: Actual size (in bytes) of decrypted content

How could you estimate the size of the decrypted content buffer for the outputBufferSize/outputBufferSize ?

In your example, the variable bufferSize was known as per the encryption example (size of the string to encrypt)...In real cases, we wouldn't know that information upfront.

byte[] decryptedBuffer = new byte[bufferSize];
var bytesDecrypted = consumptionHandler.DecryptBuffer(0, encryptedTextBuffer, decryptedBuffer, true);

I see a GetProtectedContentLength but no correspondence for a GetUnProtectedContentLength.

Let me know.

Document Details

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• ID: 625e09a4-3fcf-57c9-c62c-5aea6c8e9d86
• Version Independent ID: 7151e733-3b59-a817-8cef-a5dfc3a2ddd2
• Content: Quickstart - Encrypt/Decrypt text using the C# MIP Protection SDK
• Content Source: mip/develop/quick-protection-encrypt-decrypt-text-csharp.md
• Service: information-protection
• GitHub Login: @msmbaldwin
• Microsoft Alias: mbaldwin