字符串的SubtleCrypto ArrayBuffer键

Question

我一直在研究SublteCrypto来加密/解密文本消息，并希望提取用于字符串的密钥，但是使用相同的接口"SubtleCrypto“会为密钥生成奇怪的字符串。

下面是我正在使用的代码：

    Internal.crypto = {
    getRandomBytes: function(size) {
        var array = new Uint8Array(size);
        crypto.getRandomValues(array);
        return array.buffer;
    },
    encrypt: function(key, data, iv) {
        return crypto.subtle.importKey('raw', key, {name: 'AES-CBC'}, false, ['encrypt']).then(function(key) {
            return crypto.subtle.encrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, data);
        });
    },
    decrypt: function(key, data, iv) {
        return crypto.subtle.importKey('raw', key, {name: 'AES-CBC'}, false, ['decrypt']).then(function(key) {
            return crypto.subtle.decrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, data);
        });
    },
    sign: function(key, data) {
        return crypto.subtle.importKey('raw', key, {name: 'HMAC', hash: {name: 'SHA-256'}}, false, ['sign']).then(function(key) {
            return crypto.subtle.sign( {name: 'HMAC', hash: 'SHA-256'}, key, data);
        });
    },

    hash: function(data) {
        return crypto.subtle.digest({name: 'SHA-512'}, data);
    },

    HKDF: function(input, salt, info) {
        // Specific implementation of RFC 5869 that only returns the first 3 32-byte chunks
        // TODO: We dont always need the third chunk, we might skip it
        return Internal.crypto.sign(salt, input).then(function(PRK) {
            var infoBuffer = new ArrayBuffer(info.byteLength + 1 + 32);
            var infoArray = new Uint8Array(infoBuffer);
            infoArray.set(new Uint8Array(info), 32);
            infoArray[infoArray.length - 1] = 1;
            return Internal.crypto.sign(PRK, infoBuffer.slice(32)).then(function(T1) {
                infoArray.set(new Uint8Array(T1));
                infoArray[infoArray.length - 1] = 2;
                return Internal.crypto.sign(PRK, infoBuffer).then(function(T2) {
                    infoArray.set(new Uint8Array(T2));
                    infoArray[infoArray.length - 1] = 3;
                    return Internal.crypto.sign(PRK, infoBuffer).then(function(T3) {
                        return [ T1, T2, T3 ];
                    });
                });
            });
        });
    },

    // Curve 25519 crypto
    createKeyPair: function(privKey) {
        if (privKey === undefined) {
            privKey = Internal.crypto.getRandomBytes(32);
        }
        return Internal.Curve.async.createKeyPair(privKey);
    },
    ECDHE: function(pubKey, privKey) {
        return Internal.Curve.async.ECDHE(pubKey, privKey);
    },
    Ed25519Sign: function(privKey, message) {
        return Internal.Curve.async.Ed25519Sign(privKey, message);
    },
    Ed25519Verify: function(pubKey, msg, sig) {
        return Internal.Curve.async.Ed25519Verify(pubKey, msg, sig);
    }
};

为了获得字符串中的密钥，我更改了以下内容：

    encrypt: function(key, data, iv) {
        var sKey = String.fromCharCode.apply(null, new Uint8Array(key));
        console.log('key ' + sKey);
        return crypto.subtle.importKey('raw', key, {name: 'AES-CBC'}, true, ['encrypt']).then(function(key) {
            return crypto.subtle.encrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, data);
        });
    },
    decrypt: function(key, data, iv) {
        var sKey = String.fromCharCode.apply(null, new Uint8Array(key));
        console.log('key ' + sKey);
        return crypto.subtle.importKey('raw', key, {name: 'AES-CBC'}, true, ['decrypt']).then(function(key) {
            return crypto.subtle.decrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, data);
        });
    }

我知道key在encrypt: function(key, data, iv)和decrypt: function(key, data, iv)中是在ArrayBuffer中，但是我已经尝试了从ArrayBuffer到String的所有转换，它总是产生不正确的编码字符串，比如Sask���ç é

Answer 1

加密密钥不是文本，也不是以字节编码的文本。它是一个随机字节序列，因此试图将其解码为字符串可能会不可避免地丢失数据。

相反，使用base-64编码(btoa())和解码(atob())将二进制数据转换为字符串并再次返回。密码文本也是如此。