NPM 'crypto' returning different hash values than online generators (node)

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I am probably not using the crypto module correctly, maybe someone can help me out.

The goal is to find the sha-256 hash of a file dropped in a dropzone. The problem is that the hash being returned is different from online hash checkers (which are returning the seemingly correct values). Here is my code:

const crypto = require("crypto");

const hash = crypto.createHash("sha256");



handleOnDrop = file => {

    hash.update(file);

    const hashOutput = hash.digest("hex");

    console.log(hashOutput);

  };

Crypto docs - https://nodejs.org/api/crypto.html#crypto_node_js_crypto_constants

I am fairly sure the hash values I am getting from this code is not just the file name, I checked a few permutations with the online checkers.

Any ideas? Thanks!

edited Jan 3 at 23:49

asked Jan 3 at 22:06

Hanley Soilsmith

18210

What is file?

– Josh Lee
Jan 3 at 22:08

And what is hash? How do you create it?

– Styx
Jan 3 at 22:29

File is input as a blob by the client (through react-dropzone). Hash is from the crypto docs, I edited the original post to include that. Thanks

– Hanley Soilsmith
Jan 3 at 23:49

add a comment |

I am probably not using the crypto module correctly, maybe someone can help me out.

const crypto = require("crypto");

const hash = crypto.createHash("sha256");



handleOnDrop = file => {

    hash.update(file);

    const hashOutput = hash.digest("hex");

    console.log(hashOutput);

  };

Crypto docs - https://nodejs.org/api/crypto.html#crypto_node_js_crypto_constants

I am fairly sure the hash values I am getting from this code is not just the file name, I checked a few permutations with the online checkers.

Any ideas? Thanks!

edited Jan 3 at 23:49

asked Jan 3 at 22:06

Hanley Soilsmith

18210

What is file?

– Josh Lee
Jan 3 at 22:08

And what is hash? How do you create it?

– Styx
Jan 3 at 22:29

File is input as a blob by the client (through react-dropzone). Hash is from the crypto docs, I edited the original post to include that. Thanks

– Hanley Soilsmith
Jan 3 at 23:49

add a comment |

I am probably not using the crypto module correctly, maybe someone can help me out.

const crypto = require("crypto");

const hash = crypto.createHash("sha256");



handleOnDrop = file => {

    hash.update(file);

    const hashOutput = hash.digest("hex");

    console.log(hashOutput);

  };

Crypto docs - https://nodejs.org/api/crypto.html#crypto_node_js_crypto_constants

I am fairly sure the hash values I am getting from this code is not just the file name, I checked a few permutations with the online checkers.

Any ideas? Thanks!

edited Jan 3 at 23:49

asked Jan 3 at 22:06

Hanley Soilsmith

18210

I am probably not using the crypto module correctly, maybe someone can help me out.

const crypto = require("crypto");

const hash = crypto.createHash("sha256");



handleOnDrop = file => {

    hash.update(file);

    const hashOutput = hash.digest("hex");

    console.log(hashOutput);

  };

Crypto docs - https://nodejs.org/api/crypto.html#crypto_node_js_crypto_constants

I am fairly sure the hash values I am getting from this code is not just the file name, I checked a few permutations with the online checkers.

Any ideas? Thanks!

node.js hash sha

edited Jan 3 at 23:49

asked Jan 3 at 22:06

Hanley Soilsmith

18210

edited Jan 3 at 23:49

asked Jan 3 at 22:06

Hanley Soilsmith

18210

edited Jan 3 at 23:49

asked Jan 3 at 22:06

Hanley Soilsmith

18210

asked Jan 3 at 22:06

Hanley Soilsmith

18210

asked Jan 3 at 22:06

Hanley Soilsmith

18210

What is file?

– Josh Lee
Jan 3 at 22:08

And what is hash? How do you create it?

– Styx
Jan 3 at 22:29

File is input as a blob by the client (through react-dropzone). Hash is from the crypto docs, I edited the original post to include that. Thanks

– Hanley Soilsmith
Jan 3 at 23:49

add a comment |

What is file?

– Josh Lee
Jan 3 at 22:08

And what is hash? How do you create it?

– Styx
Jan 3 at 22:29

File is input as a blob by the client (through react-dropzone). Hash is from the crypto docs, I edited the original post to include that. Thanks

– Hanley Soilsmith
Jan 3 at 23:49

What is file?

– Josh Lee
Jan 3 at 22:08

And what is hash? How do you create it?

– Styx
Jan 3 at 22:29

File is input as a blob by the client (through react-dropzone). Hash is from the crypto docs, I edited the original post to include that. Thanks

– Hanley Soilsmith
Jan 3 at 23:49

add a comment |

1 Answer
1

active

oldest

votes

Dropzone events return a File class object, this object is based on the Blob class and doesn't provide direct access to the data of the file. In order to use the data in the file, you must use the FileReader class as outlined in the Mozilla examples

Crypto is expecting a buffer when you call hash.update, but file isn't a Buffer like it would be in these examples. Dropping a Blob into hash.update probably doesn't have the behavior you are expecting.

So, assuming you're using WebPack to provide access to the Node standard libraries, your code should need to do something like this:

  handleOnDrop = ((file) => {

    const reader = new FileReader();

    reader.onload = ((event) => {

      hash.update(Buffer.from(event.target.result));

      const hashOutput = hash.digest("hex");

      console.log(hashOutput);

    });

    reader.readAsArrayBuffer(file);

  });

answered Jan 3 at 22:47

JayReardon

515518

Code is not working as is, getting an error Error: cannot read as File: [{}] Your response is very helpful though..I think I'm on the right path, thanks

– Hanley Soilsmith
Jan 4 at 0:18

Thank you so much for taking the time. The only modification is that I place reader.readAsArrayBuffer(file) on top of reader.onload My other issue was solved by creating a new create-react-app. Not sure why that helped.

– Hanley Soilsmith
Jan 5 at 9:14

add a comment |

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1 Answer
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votes

So, assuming you're using WebPack to provide access to the Node standard libraries, your code should need to do something like this:

  handleOnDrop = ((file) => {

    const reader = new FileReader();

    reader.onload = ((event) => {

      hash.update(Buffer.from(event.target.result));

      const hashOutput = hash.digest("hex");

      console.log(hashOutput);

    });

    reader.readAsArrayBuffer(file);

  });

answered Jan 3 at 22:47

JayReardon

515518

Code is not working as is, getting an error Error: cannot read as File: [{}] Your response is very helpful though..I think I'm on the right path, thanks

– Hanley Soilsmith
Jan 4 at 0:18

Thank you so much for taking the time. The only modification is that I place reader.readAsArrayBuffer(file) on top of reader.onload My other issue was solved by creating a new create-react-app. Not sure why that helped.

– Hanley Soilsmith
Jan 5 at 9:14

add a comment |

So, assuming you're using WebPack to provide access to the Node standard libraries, your code should need to do something like this:

  handleOnDrop = ((file) => {

    const reader = new FileReader();

    reader.onload = ((event) => {

      hash.update(Buffer.from(event.target.result));

      const hashOutput = hash.digest("hex");

      console.log(hashOutput);

    });

    reader.readAsArrayBuffer(file);

  });

answered Jan 3 at 22:47

JayReardon

515518

Code is not working as is, getting an error Error: cannot read as File: [{}] Your response is very helpful though..I think I'm on the right path, thanks

– Hanley Soilsmith
Jan 4 at 0:18

Thank you so much for taking the time. The only modification is that I place reader.readAsArrayBuffer(file) on top of reader.onload My other issue was solved by creating a new create-react-app. Not sure why that helped.

– Hanley Soilsmith
Jan 5 at 9:14

add a comment |

So, assuming you're using WebPack to provide access to the Node standard libraries, your code should need to do something like this:

  handleOnDrop = ((file) => {

    const reader = new FileReader();

    reader.onload = ((event) => {

      hash.update(Buffer.from(event.target.result));

      const hashOutput = hash.digest("hex");

      console.log(hashOutput);

    });

    reader.readAsArrayBuffer(file);

  });

answered Jan 3 at 22:47

JayReardon

515518

So, assuming you're using WebPack to provide access to the Node standard libraries, your code should need to do something like this:

  handleOnDrop = ((file) => {

    const reader = new FileReader();

    reader.onload = ((event) => {

      hash.update(Buffer.from(event.target.result));

      const hashOutput = hash.digest("hex");

      console.log(hashOutput);

    });

    reader.readAsArrayBuffer(file);

  });

answered Jan 3 at 22:47

JayReardon

515518

answered Jan 3 at 22:47

JayReardon

515518

answered Jan 3 at 22:47

JayReardon

515518

answered Jan 3 at 22:47

JayReardon

515518

Code is not working as is, getting an error Error: cannot read as File: [{}] Your response is very helpful though..I think I'm on the right path, thanks

– Hanley Soilsmith
Jan 4 at 0:18

Thank you so much for taking the time. The only modification is that I place reader.readAsArrayBuffer(file) on top of reader.onload My other issue was solved by creating a new create-react-app. Not sure why that helped.

– Hanley Soilsmith
Jan 5 at 9:14

add a comment |

Code is not working as is, getting an error Error: cannot read as File: [{}] Your response is very helpful though..I think I'm on the right path, thanks

– Hanley Soilsmith
Jan 4 at 0:18

Thank you so much for taking the time. The only modification is that I place reader.readAsArrayBuffer(file) on top of reader.onload My other issue was solved by creating a new create-react-app. Not sure why that helped.

– Hanley Soilsmith
Jan 5 at 9:14

Code is not working as is, getting an error Error: cannot read as File: [{}] Your response is very helpful though..I think I'm on the right path, thanks

– Hanley Soilsmith
Jan 4 at 0:18

Thank you so much for taking the time. The only modification is that I place reader.readAsArrayBuffer(file) on top of reader.onload My other issue was solved by creating a new create-react-app. Not sure why that helped.

– Hanley Soilsmith
Jan 5 at 9:14

add a comment |

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