crypto: privateEncrypt & publicDecrypt Implementation #477

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1. calvinmetcalf commented on Jan 17, 2015

   

   calvinmetcalf

   on Jan 17, 2015

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   I'm not sure the question, they are in iojs
2. bnoordhuis

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   cryptoIssues and PRs related to the crypto subsystem.Issues and PRs related to the crypto subsystem.

   on Jan 17, 2015
3. Fishrock123 commented on Jan 19, 2015

   

   Fishrock123

   on Jan 19, 2015

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   @calvinmetcalf Those are the opposite of what they are asking.

   publicEncrypt & privateDecrypt vs (their) privateEncrypt & publicDecrypt, assuming they are wanting the correct things.
4. fuson commented on Jan 19, 2015

   

   fuson

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   Fishrock123, correct.
5. calvinmetcalf commented on Jan 19, 2015

   

   calvinmetcalf

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   ah missred, if you turn off padding and use privateDecrypt on plain text you will get ciphertext that can be decrypted with publicEncrypt
6. bnoordhuis commented on Jan 19, 2015

   

   bnoordhuis

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   @calvinmetcalf Is that process completely symmetric? My initial hunch was that the result from crypto.privateDecrypt() would get bumped to cipher block size even with RSA_NO_PADDING, and a quick test seems to confirm that.
7. calvinmetcalf commented on Jan 19, 2015

   

   calvinmetcalf

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   what do you mean by cipher block size in this context modulus size?
8. bnoordhuis commented on Jan 19, 2015

   

   bnoordhuis

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   @calvinmetcalf This, basically:

   var options = { key: key, padding: constants.RSA_NO_PADDING };
   var encrypted = crypto.privateDecrypt(options, 'plaintext');  // encrypted.length == 128
   var decrypted = crypto.publicEncrypt(options, encrypted);  // decrypted.length == 128
   // decrypted consists of 119 zero bytes followed by the original plaintext
9. calvinmetcalf commented on Jan 19, 2015

   

   calvinmetcalf

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   yes it's left padded up to the modulus length, it likely does it when you do

   var options = { key: key, padding: constants.RSA_NO_PADDING };
   var encrypted = crypto.publicEncrypt(options, 'plaintext');  // encrypted.length == 128
   var decrypted = crypto.privateDecrypt(options, encrypted); 
   

   as well (can't check at the moment). It's enough functionality to write your own padding/unpadding on top of it
10. calvinmetcalf commented on Jan 21, 2015

    

    calvinmetcalf

    on Jan 21, 2015

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    to follow up , @bnoordhuis you are correct that it is not symmetric,

    var encrypted = crypto.publicEncrypt(options, new Buffer('plaintext'));

    throws an error unless you left pad it with zeros yourself, privateDecrypt left pads it for you because the output of publicEncrypt will omit a leading zeros (for instance with this key var encrypted = crypto.privateDecrypt(options, new Buffer('plaintext')); creates an output of 127 bytes.
11. indutny commented on Jan 27, 2015

    

    indutny

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    It can't be symmetric, there is a prefix byte that does a thing.
12. indutny commented on Jan 27, 2015

    

    indutny

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    I'm going to work on it.
13. indutny

    self-assigned this

    on Jan 27, 2015
14. Fishrock123

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    enhancement

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    unconfirmed

    on Jan 27, 2015
15. indutny

    added a commit that references this issue on Jan 27, 2015

    crypto: implement privateEncrypt/publicDecrypt

    ...

    This issue will close once commit 5bb2b2d is merged into the 'v0.12' branch.

    5bb2b2d
16. indutny commented on Jan 27, 2015

    

    indutny

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    See #625
17. indutny

    closed this as completedin 87e62bdon Jan 27, 2015
18. indutny commented on Jan 27, 2015

    

    indutny

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    Shall be fixed in 87e62bd
19. briansmith

    added a commit that references this issue on Jan 28, 2016

    Tweaks for node.js

    ...

    ce9d85e
20. sjarmak

    added a commit that references this issue on Jul 27, 2026

    crypto: implement privateEncrypt/publicDecrypt

    ...

    This issue will close once commit 87e62bd is merged into the 'main' branch.

    87e62bd