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bitwiseshiftleft / sjcl

Stanford Javascript Crypto Library
http://bitwiseshiftleft.github.com/sjcl/
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EC point not on the curve! (java to sjcl) #392

Open matteobertozzi opened 5 years ago

matteobertozzi commented 5 years ago

I'm trying to share EC public keys between java and javascript.

In java I'm using the KeyPairGenerator with "secp256r1", and for test I've exported a bunch of keys: base64(x + y)

public static KeyPair generateKeyPairP256()
    throws NoSuchAlgorithmException, InvalidAlgorithmParameterException {
  final KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC");
  keyPairGenerator.initialize(new ECGenParameterSpec("secp256r1"));
  return keyPairGenerator.generateKeyPair();
}

// generate and export the keys to test
for (int i = 0; i < 20; ++i) {
  final ECPublicKey pubkey = (ECPublicKey)EcUtil.generateKeyPairP256().getPublic();
  System.out.println(Base64.getEncoder().encodeToString(BytesUtil.concat(
    pubkey.getW().getAffineX().toByteArray(),
    pubkey.getW().getAffineY().toByteArray()
  )));
}

In javascript I'm creating the public key from the base64(x + y) but only few keys seems to be valid, most of them are rejected as 'not on the curve'.

const keys = [
  /* not on the curve! */ 'ANLIxVyDuBnss2KeByZwmPDV+Y/YYxVrf/+cx+kbfM2hAOX5v8hK3TyzaufifwlBqFGdeaG2lQvxMndaSHl3mI45',
  /* ok */ 'O08/Q5Yhv9T1Rl+ci8hyTUt8TtJtK9iJ0bqIzdkonXQ084s2TuzdMkIN+vwY0sEvdvl/ww8kXnsYxHwOT63eag==',
  /* not on the curve! */ 'AJvBwTlKWvETW8h9He80q7ZPPemT0lF0Q3s1AK9YamwHAJ6KAPd1t4mWrbFXkD8xVBe9HSMvfoGQxfIFutgaGhV1',
  /* not on the curve! */ 'ALbm8zY++oby4etNH+k5ORdzHzHyQtVfevWg/0db3bGyVwf1QUdgGD13RcVTZwwt0xW4AB+C0gFCCTdRa6aEb0Q=',
  /* not on the curve! */ 'Y1wStfsy6o8GqsoqvLFhV2f0WZRw60QLSkA6hek7QZkA+tuU2SUoJmFVHa7g3oQLknwQWaKmzJYwQ6/zuqGLYUg=',
  /* not on the curve! */ 'ALYhkfg+rrBgAFNG29dG6CUHkIuYGSF3K45ao6C0R6hAAL7GvZR6v1d/J7p7hGDABRx1nUk8aIhFzpXPWBl0g/Z1',
  /* not on the curve! */ 'OyU6ExPtTgBRB4Gka5a3sGv3lTsAd0x7AxRV/+66WAQAgKotZoBsM53azsy7FLJz68AoJMc3UzOregIyvqC/WkI=',
  /* ok */ 'ZcTaVPTm3bHB33kHXqQX1Frbbp09zZhj6rLf3t4dBe09mnqnOi9AvG3oHNQcGoU4mBvWJ2wLc16WjJRk/gfyRQ==',
  /* not on the curve! */ 'AOSB0wyJkd/VrFmgEPp16S+vtkCZPEi+ca6Vd5bpjrCPAK1HzI8KCXvRHAtfXJyj70BmNR/y5NFDsd5XGVFisZAX',
  /* not on the curve! */ 'AJU6UPZHcMdWNv5CBl56phat9EHOTnQ9Z4ujzVRZKtouAJ/rjqSVRABTUYMxmRWbHA5usGRdnSKJg47gzoGnD+9+',
  /* not on the curve! */ 'AI8beSdfWlDNYVockAYvAjbtomN9I6Zr+j09o/f/Gx2OAIr88YdNQKCV716JEbDVVMO7X6eNOHFDakG/zPQkW3d2',
  /* ok */ 'IygMA2ErCPvfEzKcRLt9ICI26frZKVbN5UoorFn51FVJhOAUvoBv8YSDaFBeuidtfdE9NhKL3p5OFcoA9hpn7w==',
  /* not on the curve! */ 'SK1a8SIvjjyZQUGRXa2pLzV5d/bqH0MLeQrAvFky6BoAl0TB7B9K7Y+p2y14qEwgSI6UqGCwa4jAxeiL6b8pFto=',
  /* not on the curve! */ 'AIpM5MTWLNf/BvcaLseBx1Cn5w7NmVCJubr+9s2AOYTudyhTWPGzRzGF3/G/AjfKY1T3cQzOWc+CFN4BV3gohyM=',
  /* not on the curve! */ 'ALC9GT5WbO1cQbGCGPfC7Jgrnxf4nUnL6att+Ut2LEhLAN2S36VvA2jVfQi7VA4/fF383vkfRyyN2ROiJekO8gmu',
  /* ok */ 'fo18bFMaiX1eQPBIv9HtKwS0Zlng69bZ3pbIlyB5oMhceaRWBQZnlGPWvbM+RpWCkf4l3km/WWcQuSSneeldfg==',
  /* not on the curve! */ 'APg6AAdqPF/8el8QfARKNKewuqiJodz4oK7v9DXlKphJJzTuCHzeV8+w3CrEIsr9SslMTzoVox39RHIL/HMSi74=',
  /* not on the curve! */ 'AKwPjAvakqEtszhRbWae0gPUC3+Gg7/GMAMNH3d6tcbAHvXKj+YY4UF/+9woqMTYTpTWkmkQcHA6k1vVqNJI2dw=',
  /* not on the curve! */ 'AMTWHCNxCKGe7+Ml7EmjLPCpkWmIZMaVcrDKOds+Ev0VE4IyuSVAyqa62QrN22giZLsJCc9CR1iFP2uxY10MhMo=',
  /* ok */ 'cGeG8rOatkcrsJFkHcJ7bU+BqCLJKY552oM1K6czHhxycnZaf/N3A2G+w/+WZaSCWS3P7zKKAXl090GAeBw4qA==',
];
for (let i = 0; i < keys.length; ++i) {
  try {
    const pubkey = new sjcl.ecc.elGamal.publicKey(
      sjcl.ecc.curves.c256,
      sjcl.codec.base64.toBits(keys[i])
    );
    console.log('OK', keys[i], pubkey);
  } catch(e) {
    console.log(e.message, keys[i]);
  }
}

Are there more parameters required to pass to the java key generator or the sjcl publickey constructor, or is there a bug in the sjcl parse?

(if there are more parameters or different parameters required, maybe we can add a section to the wiki to show how to generate and export from java)

jmkf commented 5 years ago

I suspect on the Java side you make an error converting 256 bits to base 64 by going through a signed number. Make sure you don't leave off leading zeros or add one extra byte to keep a signed number positive. (That last one probably explains the Overrepresentation of leading A characters in the wrong points)Br Martijn On May 2, 2019 08:08, Matteo Bertozzi notifications@github.com wrote:I'm trying to share EC public keys between java and javascript. In java I'm using the KeyPairGenerator with "secp256r1", and for test I've exported a bunch of keys: base64(x + y) public static KeyPair generateKeyPairP256() throws NoSuchAlgorithmException, InvalidAlgorithmParameterException { final KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC"); keyPairGenerator.initialize(new ECGenParameterSpec("secp256r1")); return keyPairGenerator.generateKeyPair(); }

// generate and export the keys to test for (int i = 0; i < 20; ++i) { final ECPublicKey pubkey = (ECPublicKey)EcUtil.generateKeyPairP256().getPublic(); System.out.println(Base64.getEncoder().encodeToString(BytesUtil.concat( pubkey.getW().getAffineX().toByteArray(), pubkey.getW().getAffineY().toByteArray() ))); } In javascript I'm creating the public key from the base64(x + y) but only few keys seems to be valid, most of them are rejected as 'not on the curve'. const keys = [ / not on the curve! / 'ANLIxVyDuBnss2KeByZwmPDV+Y/YYxVrf/+cx+kbfM2hAOX5v8hK3TyzaufifwlBqFGdeaG2lQvxMndaSHl3mI45', / ok / 'O08/Q5Yhv9T1Rl+ci8hyTUt8TtJtK9iJ0bqIzdkonXQ084s2TuzdMkIN+vwY0sEvdvl/ww8kXnsYxHwOT63eag==', / not on the curve! / 'AJvBwTlKWvETW8h9He80q7ZPPemT0lF0Q3s1AK9YamwHAJ6KAPd1t4mWrbFXkD8xVBe9HSMvfoGQxfIFutgaGhV1', / not on the curve! / 'ALbm8zY++oby4etNH+k5ORdzHzHyQtVfevWg/0db3bGyVwf1QUdgGD13RcVTZwwt0xW4AB+C0gFCCTdRa6aEb0Q=', / not on the curve! / 'Y1wStfsy6o8GqsoqvLFhV2f0WZRw60QLSkA6hek7QZkA+tuU2SUoJmFVHa7g3oQLknwQWaKmzJYwQ6/zuqGLYUg=', / not on the curve! / 'ALYhkfg+rrBgAFNG29dG6CUHkIuYGSF3K45ao6C0R6hAAL7GvZR6v1d/J7p7hGDABRx1nUk8aIhFzpXPWBl0g/Z1', / not on the curve! / 'OyU6ExPtTgBRB4Gka5a3sGv3lTsAd0x7AxRV/+66WAQAgKotZoBsM53azsy7FLJz68AoJMc3UzOregIyvqC/WkI=', / ok / 'ZcTaVPTm3bHB33kHXqQX1Frbbp09zZhj6rLf3t4dBe09mnqnOi9AvG3oHNQcGoU4mBvWJ2wLc16WjJRk/gfyRQ==', / not on the curve! / 'AOSB0wyJkd/VrFmgEPp16S+vtkCZPEi+ca6Vd5bpjrCPAK1HzI8KCXvRHAtfXJyj70BmNR/y5NFDsd5XGVFisZAX', / not on the curve! / 'AJU6UPZHcMdWNv5CBl56phat9EHOTnQ9Z4ujzVRZKtouAJ/rjqSVRABTUYMxmRWbHA5usGRdnSKJg47gzoGnD+9+', / not on the curve! / 'AI8beSdfWlDNYVockAYvAjbtomN9I6Zr+j09o/f/Gx2OAIr88YdNQKCV716JEbDVVMO7X6eNOHFDakG/zPQkW3d2', / ok / 'IygMA2ErCPvfEzKcRLt9ICI26frZKVbN5UoorFn51FVJhOAUvoBv8YSDaFBeuidtfdE9NhKL3p5OFcoA9hpn7w==', / not on the curve! / 'SK1a8SIvjjyZQUGRXa2pLzV5d/bqH0MLeQrAvFky6BoAl0TB7B9K7Y+p2y14qEwgSI6UqGCwa4jAxeiL6b8pFto=', / not on the curve! / 'AIpM5MTWLNf/BvcaLseBx1Cn5w7NmVCJubr+9s2AOYTudyhTWPGzRzGF3/G/AjfKY1T3cQzOWc+CFN4BV3gohyM=', / not on the curve! / 'ALC9GT5WbO1cQbGCGPfC7Jgrnxf4nUnL6att+Ut2LEhLAN2S36VvA2jVfQi7VA4/fF383vkfRyyN2ROiJekO8gmu', / ok / 'fo18bFMaiX1eQPBIv9HtKwS0Zlng69bZ3pbIlyB5oMhceaRWBQZnlGPWvbM+RpWCkf4l3km/WWcQuSSneeldfg==', / not on the curve! / 'APg6AAdqPF/8el8QfARKNKewuqiJodz4oK7v9DXlKphJJzTuCHzeV8+w3CrEIsr9SslMTzoVox39RHIL/HMSi74=', / not on the curve! / 'AKwPjAvakqEtszhRbWae0gPUC3+Gg7/GMAMNH3d6tcbAHvXKj+YY4UF/+9woqMTYTpTWkmkQcHA6k1vVqNJI2dw=', / not on the curve! / 'AMTWHCNxCKGe7+Ml7EmjLPCpkWmIZMaVcrDKOds+Ev0VE4IyuSVAyqa62QrN22giZLsJCc9CR1iFP2uxY10MhMo=', / ok / 'cGeG8rOatkcrsJFkHcJ7bU+BqCLJKY552oM1K6czHhxycnZaf/N3A2G+w/+WZaSCWS3P7zKKAXl090GAeBw4qA==', ]; for (let i = 0; i < keys.length; ++i) { try { const pubkey = new sjcl.ecc.elGamal.publicKey( sjcl.ecc.curves.c256, sjcl.codec.base64.toBits(keys[i]) ); console.log('OK', keys[i], pubkey); } catch(e) { console.log(e.message, keys[i]); } } Are there more parameters required to pass to the java key generator or the sjcl publickey constructor, or is there a bug in the sjcl parse? (if there are more parameters or different parameters required, maybe we can add a section to the wiki to show how to generate and export from java)

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