我正在构建一个 Web API，我需要实现 ECDH 来执行端到端加密。在服务器端我有一个 C# 应用程序，在客户端我有一个 Javascript 应用程序。我能够交换密钥、生成私钥并加密消息，但我在解密时遇到了问题。我认为问题在于公钥的交换。在 javascript 中，键以字节“4”开头，.NET 键以 8 个字节开头，用于标识键的类型和大小，我需要更改这些字节以导入每个键（我在这里找到的信息）。也许这会导致一些不一致。在客户端，我使用 Web Cryptography API 来处理 ECDH。我正在实施如下。生成密钥await window.crypto.subtle.generateKey( { name: "ECDH", namedCurve: "P-256", }, false, ["deriveKey", "deriveBits"] );像这样导出公钥：await window.crypto.subtle.exportKey( "raw", publicKey );导入外部公钥await window.crypto.subtle.importKey( "raw", { name: "ECDH", namedCurve: "P-256", }, false, ["deriveKey", "deriveBits"] )最后推导出密钥await window.crypto.subtle.deriveKey( { name: "ECDH", namedCurve: "P-256", public: publicKey, }, privateKey, { name: "AES-CBC", length: 256, }, false, ["encrypt", "decrypt"] )在服务器端，我正在实施以下相同的步骤。生成公钥private static ECDiffieHellmanCng ecdh = new ECDiffieHellmanCng(256);public static void GeneratePublicKey(){ ecdh.KeyDerivationFunction = ECDiffieHellmanKeyDerivationFunction.Hash; ecdh.HashAlgorithm = CngAlgorithm.Sha256; publicKey = ecdh.PublicKey.ToByteArray();}导出公钥。请注意，我更改了第一个字节public static byte[] GetPublicKey() { var auxKey = publicKey.Skip(7).ToArray(); auxKey[0] = 4; return auxKey; }导入公钥并导出私钥。请注意，我更改了第一个字节public static void GerarChavePrivada(byte[] bobPublicKey){ byte[] aux = new byte[bobPublicKey.Length + 7]; aux[0] = 0x45; aux[1] = 0x43; aux[2] = 0x4B; aux[3] = 0x31; aux[4] = 0x20; aux[5] = 0x00; aux[6] = 0x00; aux[7] = 0x00; for (int i = 1; i < bobPublicKey.Length; i++) { aux[7 + i] = bobPublicKey[i]; } var importedKey = CngKey.Import(aux, CngKeyBlobFormat.EccPublicBlob); privateKey = ecdh.DeriveKeyMaterial(importedKey);}
3 回答
qq_笑_17
TA贡献1818条经验 获得超7个赞
我遇到过同样的问题。经过更多调试后，我意识到 C# 使用 DeriveKeyMaterial 生成的密钥然后使用 SHA-256 进行哈希处理。
我的解决方案是在 javascript 上导出派生密钥，对其进行哈希处理，然后将其作为新密钥导入。
cryptoApi().deriveKey(
{
name: "ECDH",
namedCurve: "P-256", //can be "P-256", "P-384", or "P-521"
public: ServerKey, //an ECDH public key from generateKey or importKey
},
ECkey.privateKey, //your ECDH private key from generateKey or importKey
{ //the key type you want to create based on the derived bits
name: "AES-CBC", //can be any AES algorithm ("AES-CTR", "AES-CBC", "AES-CMAC", "AES-GCM", "AES-CFB", "AES-KW", "ECDH", "DH", or "HMAC")
//the generateKey parameters for that type of algorithm
length: 256, //can be 128, 192, or 256
},
true, //whether the derived key is extractable (i.e. can be used in exportKey)
["encrypt", "decrypt"] //limited to the options in that algorithm's importKey
)
.then(function(AESKeyData){
//returns the exported key data
console.log(AESKeyData);
cryptoApi().exportKey('raw',
AESKeyData
).then(function (exportedAESKeyData) {
cryptoApi().digest('SHA-256', exportedAESKeyData).then(function (HashedAESKeyValue) {
console.log(HashedAESKeyValue);
cryptoApi().importKey(
'raw',
HashedAESKeyValue,
{ //the key type you want to create based on the derived bits
name: "AES-CBC", //can be any AES algorithm ("AES-CTR", "AES-CBC", "AES-CMAC", "AES-GCM", "AES-CFB", "AES-KW", "ECDH", "DH", or "HMAC")
//the generateKey parameters for that type of algorithm
length: 256, //can be 128, 192, or 256
},
false,
["encrypt", "decrypt"]
).then(function (TrueAESKey) {
cryptoApi().decrypt(
{
name: 'AES-CBC',
length: 256,
iv: base64ToArrayBuffer(IV)
},
TrueAESKey,
base64ToArrayBuffer(EncryptedData)
).then(function (decrypted) {
console.log(buf2hex(decrypted));
});
})
});
});
})
FFIVE
TA贡献1797条经验 获得超6个赞
尝试这样做
要点中的完整示例
class Protector {
ab2str(buffer) {
return new TextDecoder().decode(buffer);
}
str2ab(text) {
return new TextEncoder().encode(text);
}
generateIv() {
return crypto.getRandomValues(new Uint8Array(16));
}
/**
* @see https://github.com/mdn/dom-examples/blob/master/web-crypto/derive-bits/ecdh.js
*/
async generateKey() {
this.key = await window.crypto.subtle.generateKey(
{ name: 'ECDH', namedCurve: 'P-256' },
false,
['deriveBits']
);
}
async encrypt(plaintext) {
const counter = this.generateIv();
const buffer = await crypto.subtle.decrypt({
name: 'aes-ctr',
counter: counter,
length: 128
}, this.importedKey, this.str2ab(plaintext));
return { buffer, counter };
}
async decrypt(data) {
const buffer = await crypto.subtle.decrypt({
name: 'aes-ctr',
counter: data.counter,
length: 128
}, this.importedKey, data.buffer);
return this.ab2str(buffer);
}
getPublicKey() {
return {publicKey: this.key.publicKey};
}
async setRemotePublicKey(key) {
this.clientKey = key;
this.sharedSecret = await window.crypto.subtle.deriveBits(
{ name: 'ECDH', namedCurve: 'P-256', public: this.clientKey.publicKey },
this.key.privateKey,
256
);
this.importedKey = await crypto.subtle.importKey(
'raw',
this.sharedSecret,
'aes-ctr',
false,
['encrypt', 'decrypt']
);
}
}
如何使用：
(async () => {
// Generate Keys
const pro1 = new Protector();
await pro1.generateKey();
const pub1 = pro1.getPublicKey();
const pro2 = new Protector();
await pro2.generateKey();
const pub2 = pro2.getPublicKey();
// Exchange Keys
await pro1.setRemotePublicKey(pub2);
await pro2.setRemotePublicKey(pub1);
// Let`s Encrypt
const crypted = await pro1.encrypt('Hello World');
const descrypted = await pro2.decrypt(crypted);
})();
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