JS SubtleCrypto RSA加密和解密

Question

所以我正在尝试实现一些方法来加密然后解密一些数据。我对此没有任何经验，我试着在网上发布了一些关于如何做到这一点的文章。

当我将加密的'hello‘传递给decrypt函数时，会得到如下结果：

let a = importPublicKeyAndEncrypt('hello')

CryptoKey {type: "public", extractable: true, algorithm: {…}, usages: Array(1)} W29iamVjdCBBcnJheUJ1ZmZlcl0=

importPrivateKeyAndDecrypt(a)
Promise {<pending>}

DOMException: Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded.
at importPrivateKeyAndDecrypt (<anonymous>:26:60)

当我使用来自我在PKCS#8上看到的帖子中的加密消息时，解密功能可以正常工作，但当我生成自己的密钥时，解密功能却无法正常工作。

下面是代码，我做错了什么？

// PEM encoded X.509 key
const publicKey = `
-----BEGIN PUBLIC KEY-----
    <removed for space>
-----END PUBLIC KEY-----`;

// PEM encoded PKCS#8 key
const privateKey = `
-----BEGIN PRIVATE KEY-----
    <removed for space>
-----END PRIVATE KEY-----`;

async function importPublicKeyAndEncrypt(str) {
  try {
    const pub = await importPublicKey(publicKey);
    console.log(pub);
    const encrypted = await encryptRSA(pub, new TextEncoder().encode(str));
    const encryptedBase64 = window.btoa(ab2str(encrypted));
    console.log(encryptedBase64.replace(/(.{64})/g, '$1\n'));
  } catch (error) {
    console.log(error);
  }
}

async function importPrivateKeyAndDecrypt(str) {
  try {
    const priv = await importPrivateKey(privateKey);
    const decrypted = await decryptRSA(priv, str2ab(window.atob(str)));
    console.log(decrypted);
  } catch (error) {
    console.log(error);
  }
}

async function importPublicKey(spkiPem) {
  return await window.crypto.subtle.importKey(
    'spki',
    getSpkiDer(spkiPem),
    {
      name: 'RSA-OAEP',
      hash: 'SHA-256',
    },
    true,
    ['encrypt']
  );
}

async function importPrivateKey(pkcs8Pem) {
  return await window.crypto.subtle.importKey(
    'pkcs8',
    getPkcs8DerDecode(pkcs8Pem),
    {
      name: 'RSA-OAEP',
      hash: 'SHA-256',
    },
    true,
    ['decrypt']
  );
}

async function encryptRSA(key, plaintext) {
  let encrypted = await window.crypto.subtle.encrypt(
    {
      name: 'RSA-OAEP',
    },
    key,
    plaintext
  );
  return encrypted;
}

async function decryptRSA(key, ciphertext) {
  let decrypted = await window.crypto.subtle.decrypt(
    {
      name: 'RSA-OAEP',
    },
    key,
    ciphertext
  );
  return new TextDecoder().decode(decrypted);
}

function getSpkiDer(spkiPem) {
  const pemHeader = '-----BEGIN PUBLIC KEY-----';
  const pemFooter = '-----END PUBLIC KEY-----';
  var pemContents = spkiPem.substring(
    pemHeader.length,
    spkiPem.length - pemFooter.length
  );
  var binaryDerString = window.atob(pemContents);
  return str2ab(binaryDerString);
}

function getPkcs8DerDecode(pkcs8Pem) {
  const pemHeader = '-----BEGIN PRIVATE KEY-----';
  const pemFooter = '-----END PRIVATE KEY-----';
  var pemContents = pkcs8Pem.substring(
    pemHeader.length,
    pkcs8Pem.length - pemFooter.length
  );
  var binaryDerString = window.atob(pemContents);
  return str2ab(binaryDerString);
}

function str2ab(str) {
  const buf = new ArrayBuffer(str.length);
  const bufView = new Uint8Array(buf);
  for (let i = 0, strLen = str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}

function ab2str(buf) {
  return String.fromCharCode.apply(null, new Uint8Array(buf));
}

Answer 1

只有两个小缺陷。

首先，importPublicKeyAndEncrypt()和importPrivateKeyAndDecrypt()中缺少return语句(尽管后者对于当前代码片段不是必需的)。

此外，在调用importPrivateKeyAndDecrypt()之前，有必要等待importPublicKeyAndEncrypt()的承诺。

有了这些修复，代码就可以工作了：

​

// PEM encoded X.509 key
const publicKey = `-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAunF5aDa6HCfLMMI/MZLT
5hDk304CU+ypFMFiBjowQdUMQKYHZ+fklB7GpLxCatxYJ/hZ7rjfHH3Klq20/Y1E
bYDRopyTSfkrTzPzwsX4Ur/l25CtdQldhHCTMgwf/Ev/buBNobfzdZE+Dhdv5lQw
KtjI43lDKvAi5kEet2TFwfJcJrBiRJeEcLfVgWTXGRQn7gngWKykUu5rS83eAU1x
H9FLojQfyia89/EykiOO7/3UWwd+MATZ9HLjSx2/Lf3g2jr81eifEmYDlri/OZp4
OhZu+0Bo1LXloCTe+vmIQ2YCX7EatUOuyQMt2Vwx4uV+d/A3DP6PtMGBKpF8St4i
GwIDAQAB
-----END PUBLIC KEY-----`;

// PEM encoded PKCS#8 key
const privateKey = `-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----`;

async function importPublicKeyAndEncrypt(str) {
  try {
    const pub = await importPublicKey(publicKey);
    //console.log(pub);
    const encrypted = await encryptRSA(pub, new TextEncoder().encode(str));
    const encryptedBase64 = window.btoa(ab2str(encrypted));
    //console.log(encryptedBase64.replace(/(.{64})/g, '$1\n'));
    return encryptedBase64;
  } catch (error) {
    console.log(error);
  }
}

async function importPrivateKeyAndDecrypt(str) {
  try {
    const priv = await importPrivateKey(privateKey);
    const decrypted = await decryptRSA(priv, str2ab(window.atob(str)));
    //console.log(decrypted);
    return decrypted;
  } catch (error) {
    console.log(error);
  }
}

async function importPublicKey(spkiPem) {
  return await window.crypto.subtle.importKey(
    'spki',
    getSpkiDer(spkiPem),
    {
      name: 'RSA-OAEP',
      hash: 'SHA-256',
    },
    true,
    ['encrypt']
  );
}

async function importPrivateKey(pkcs8Pem) {
  return await window.crypto.subtle.importKey(
    'pkcs8',
    getPkcs8DerDecode(pkcs8Pem),
    {
      name: 'RSA-OAEP',
      hash: 'SHA-256',
    },
    true,
    ['decrypt']
  );
}

async function encryptRSA(key, plaintext) {
  let encrypted = await window.crypto.subtle.encrypt(
    {
      name: 'RSA-OAEP',
    },
    key,
    plaintext
  );
  return encrypted;
}

async function decryptRSA(key, ciphertext) {
  let decrypted = await window.crypto.subtle.decrypt(
    {
      name: 'RSA-OAEP',
    },
    key,
    ciphertext
  );
  return new TextDecoder().decode(decrypted);
}

function getSpkiDer(spkiPem) {
  const pemHeader = '-----BEGIN PUBLIC KEY-----';
  const pemFooter = '-----END PUBLIC KEY-----';
  var pemContents = spkiPem.substring(
    pemHeader.length,
    spkiPem.length - pemFooter.length
  );
  var binaryDerString = window.atob(pemContents);
  return str2ab(binaryDerString);
}

function getPkcs8DerDecode(pkcs8Pem) {
  const pemHeader = '-----BEGIN PRIVATE KEY-----';
  const pemFooter = '-----END PRIVATE KEY-----';
  var pemContents = pkcs8Pem.substring(
    pemHeader.length,
    pkcs8Pem.length - pemFooter.length
  );
  var binaryDerString = window.atob(pemContents);
  return str2ab(binaryDerString);
}

function str2ab(str) {
  const buf = new ArrayBuffer(str.length);
  const bufView = new Uint8Array(buf);
  for (let i = 0, strLen = str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}

function ab2str(buf) {
  return String.fromCharCode.apply(null, new Uint8Array(buf));
}

(async () => {
    let ciphertext = await importPublicKeyAndEncrypt('hello');
    console.log("Ciphertext:\n", ciphertext.replace(/(.{48})/g, '$1\n'));
    let decryptedData = await importPrivateKeyAndDecrypt(ciphertext);
    console.log("Decrypted data:", decryptedData);
})();

​