30 lines
1.9 KiB
Markdown
30 lines
1.9 KiB
Markdown
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# Crypttool Docs
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Crypttool is an open source utility to de- and encrypt files using a symmetrical key.
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The emphasis is on using simple to use web interface to allow anyone to use symmetric encryption for e.g. Email
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attachments without installing additional software.
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The application runs entirely in the Browser and does not send any Data to the webserver beyond the main requests.
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## Usage:
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### 1. Password Generation
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The Password field is populated randomly on every page load using the [getRandomValues](https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues)
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function of the web browsers crypto API. Because this application (currently) does not use any cookies, it does not
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persist the password across sessions.
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If you want to use your own password, you can supply it by entering it in the password field and clicking "Update". Be
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careful when using a password that isn't truly randomly created, since the whole cryptography of this application is
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built on this string. Thus it is strongly advised to use a randomly generated password or passphrase.
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### 2. Encrypting a File
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To encrypt a file, you just need to drag it to the field containing the "Encrypt" button and press
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the "Encrypt button". Your browser will now encrypt the file and "download" it. The Encryption is handled using the
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[encrypt](https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/encrypt) method of the
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[SubtleCrypto](https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto) API.
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### 3. Decrypting a File
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To decrypt a file, first enter the password that was used to encrypt it in the "Password" field and click "Update".
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Then, drag the encrypted file to the field containing the "Decrypt" button.
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After pressing the "Decrypt" button, your browser should decrypt the file using the [decrypt](https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/decrypt)
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method of the SubtleCrypto API and "download" the cleartext file.
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