使用AES对称密钥(CBC模式)加解密
对应的算法规格请查看对称密钥加解密算法规格:AES。
加密
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调用cryptoFramework.createSymKeyGenerator、SymKeyGenerator.generateSymKey,生成密钥算法为AES、密钥长度为128位的对称密钥(SymKey)。
如何生成AES对称密钥,开发者可参考下文示例,并结合对称密钥生成和转换规格:AES和随机生成对称密钥理解,参考文档与当前示例可能存在入参差异,请在阅读时注意区分。
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调用cryptoFramework.createCipher,指定字符串参数'AES128|CBC|PKCS7',创建对称密钥类型为AES128、分组模式为CBC、填充模式为PKCS7的Cipher实例,用于完成加解密操作。
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调用Cipher.init,设置模式为加密(CryptoMode.ENCRYPT_MODE),指定加密密钥(SymKey)和CBC模式对应的加密参数(IvParamsSpec),初始化加密Cipher实例。
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加密内容较短时,可以不调用update,直接调用Cipher.doFinal,获取加密后的数据。
解密
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调用Cipher.init,设置模式为解密(CryptoMode.DECRYPT_MODE),指定解密密钥(SymKey)和CBC模式对应的解密参数(IvParamsSpec),初始化解密Cipher实例。
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解密内容较短时,可以不调用update,直接调用Cipher.doFinal,获取解密后的数据。
import cryptoFramework from '@ohos.security.cryptoFramework';
import buffer from '@ohos.buffer';
function genIvParamsSpec() {
let arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; // 16 bytes
let dataIv = new Uint8Array(arr);
let ivBlob: cryptoFramework.DataBlob = { data: dataIv };
let ivParamsSpec: cryptoFramework.IvParamsSpec = {
algName: "IvParamsSpec",
iv: ivBlob
};
return ivParamsSpec;
}
// 加密消息
async function encryptMessagePromise(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
let cipher = cryptoFramework.createCipher('AES128|CBC|PKCS7');
let iv = genIvParamsSpec();
await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, iv);
let cipherData = await cipher.doFinal(plainText);
return cipherData;
}
// 解密消息
async function decryptMessagePromise(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
let decoder = cryptoFramework.createCipher('AES128|CBC|PKCS7');
let iv = genIvParamsSpec();
await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, iv);
let decryptData = await decoder.doFinal(cipherText);
return decryptData;
}
async function genSymKeyByData(symKeyData: Uint8Array) {
let symKeyBlob: cryptoFramework.DataBlob = { data: symKeyData };
let aesGenerator = cryptoFramework.createSymKeyGenerator('AES128');
let symKey = await aesGenerator.convertKey(symKeyBlob);
console.info('convertKey success');
return symKey;
}
async function aesCBC() {
let keyData = new Uint8Array([83, 217, 231, 76, 28, 113, 23, 219, 250, 71, 209, 210, 205, 97, 32, 159]);
let symKey = await genSymKeyByData(keyData);
let message = "This is a test";
let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
let encryptText = await encryptMessagePromise(symKey, plainText);
let decryptText = await decryptMessagePromise(symKey, encryptText);
if (plainText.data.toString() === decryptText.data.toString()) {
console.info('decrypt ok');
console.info('decrypt plainText: ' + buffer.from(decryptText.data).toString('utf-8'));
} else {
console.error('decrypt failed');
}
}