鸿蒙系统开发【ASN.1密文转换】安全

ASN.1密文转换

介绍

本示例对使用@kit.CryptoArchitectureKit加密后的密文格式进行转换。@kit.CryptoArchitectureKit加密后的密文格式默认为以base64显示的ASN.1格式问题，通过对密文进行base64变换后得到字符数组，以16进制数字显示，再此基础上进行密文格式转换，从ASN.1格式转换为c1c3c2格式的裸密文，再以c1c3c2格式的裸密文进行解密，以验证密文转换的正确性。

效果预览

使用说明

1. 点击主页面加密按钮，对原始数据使用SM2国密算法进行加密，其内容显示在加密数据文本框中， 此时解密按钮和base64转换按钮使能
2. 点击主页面base64转换按钮，对原始密文进行base64转换，在加密数据文本框中显示转换后的密文 此时asn.1转换按钮使能
3. 点击主页面asn.1转换按钮，对密文进行asn.1转换，在加密数据文本框中显示转换后的密文 此时加密按钮和base64转换按钮去使能
4. 点击主页面解密按钮，对密文进行解密，在解密数据文本框中显示解密后的文本 此时解密按钮去使能

具体实现

• 对文本加密：在[SM2.ets] 点击加密按钮，调用加密函数实现对文本内容进行加密。点击解密按钮，调用解密函数实现对文本内容进行解密. 对消息加密的过程中采用cryptoFramework.Cipher完成加解密操作。

import { cryptoFramework } from '@kit.CryptoArchitectureKit';
import { print } from '@kit.BasicServicesKit';
import { buffer, util } from '@kit.ArkTS';
import { SM2CipherText } from './SM2CipherText';

async function genECCPubKey(key: string) {
  let mode: number = 1;
  let pk: cryptoFramework.Point = {
    x: BigInt(""),
    y: BigInt(""),
  };
  if ((mode & 0x01) != 0 && key != null) {
    pk = {
      x: BigInt("0x" + key.substring(0, 64)),
      y: BigInt("0x" + key.substring(64, 128)),
    }
  }
  let keyPairGenerator: cryptoFramework.AsyKeyGeneratorBySpec;
  let pubKeySpec: cryptoFramework.ECCPubKeySpec = {
    params: genSM2CommonSpec(),
    pk: pk,
    algName: "ECC",
    specType: cryptoFramework.AsyKeySpecType.PUBLIC_KEY_SPEC
  };
  keyPairGenerator = cryptoFramework.createAsyKeyGeneratorBySpec(pubKeySpec);
  return await keyPairGenerator.generatePubKey();
}

async function genECCPriKey(key: string) {
  let mode: number = 2;
  let sk: bigint = BigInt("");
  if ((mode & 0x02) != 0) {
    sk = BigInt("0x" + key);
  }
  let keyPairGenerator: cryptoFramework.AsyKeyGeneratorBySpec;
  let priKey: cryptoFramework.ECCPriKeySpec = {
    params: genSM2CommonSpec(),
    sk: sk,
    algName: "ECC",
    specType: cryptoFramework.AsyKeySpecType.PRIVATE_KEY_SPEC
  };
  keyPairGenerator = cryptoFramework.createAsyKeyGeneratorBySpec(priKey);
  return await keyPairGenerator.generatePriKey();
}

export function genSM2CommonSpec(): cryptoFramework.ECCCommonParamsSpec {
  let fieldFp: cryptoFramework.ECFieldFp = {
    fieldType: "Fp",
    p: BigInt("0xFFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFF")
  }

  let G: cryptoFramework.Point = {
    x: BigInt("0x32C4AE2C1F1981195F9904466A39C9948FE30BBFF2660BE1715A4589334C74C7"),
    y: BigInt("0xBC3736A2F4F6779C59BDCEE36B692153D0A9877CC62A474002DF32E52139F0A0")
  }

  let SM2CommonSpec: cryptoFramework.ECCCommonParamsSpec = {
    algName: "ECC",
    specType: cryptoFramework.AsyKeySpecType.COMMON_PARAMS_SPEC,
    field: fieldFp,
    a: BigInt("0xFFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFC"),
    b: BigInt("0x28E9FA9E9D9F5E344D5A9E4BCF6509A7F39789F515AB8F92DDBCBD414D940E93"),
    g: G,
    n: BigInt("0xFFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFF7203DF6B21C6052B53BBF40939D54123"),
    h: 1
  }
  return SM2CommonSpec;
}

export async function genSM2Key(pubKey: cryptoFramework.DataBlob | null, priKey: cryptoFramework.DataBlob | null): Promise<cryptoFramework.KeyPair> {
  let generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  return await generator.convertKey(pubKey, priKey)
}

async function encryptByPrimalKey(message: string, key: string): Promise<string> {
  let base64Helper = new util.Base64Helper();
  console.log(`key len: ${key.length}`);
  let pubKey = await genECCPubKey(key);
  let keyPair = await genSM2Key(pubKey.getEncoded(), null);
  let cipher = cryptoFramework.createCipher("SM2_256|SM3");
  await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, keyPair.pubKey, null);
  let plainTextBlob: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
  let encryptBlob = await cipher.doFinal(plainTextBlob);
  return base64Helper.encodeToStringSync(encryptBlob.data);
}

export async function encryptSM2(message: string) {
  let pubKey: string = "5A033A9DBEF84C0784C897D070E6608C5AEED39B806DF82853D64E2A686A3794" + "F9233D20DD878F642D61C2B0344988AE284646226767A1631BBB0DBB6DF40D07"
  return encryptByPrimalKey(message, pubKey);
}

async function decryptByPrimalKeyArray(messageArray: Uint8Array, key: string): Promise<string> {
  let priKey = await genECCPriKey(key);
  let keyPair = await genSM2Key(null, priKey.getEncoded());
  let cipher = cryptoFramework.createCipher("SM2_256|SM3");
  await cipher.init(cryptoFramework.CryptoMode.DECRYPT_MODE, keyPair.priKey, null);
  let plainTextBlob: cryptoFramework.DataBlob = { data: messageArray };
  let decryptBlob = await cipher.doFinal(plainTextBlob);
  return buffer.from(decryptBlob.data).toString('utf-8');
}

export async function decryptSM2(encryptedStr: string, isc1c3c2: Boolean = false): Promise<string> {
  let priKey: string = "3629EFF03FBC86711F6695CBF5590F0F2FCAAA3C269A1CA9BD64FB4C70DF9C9F"

  if (isc1c3c2) {
    let hexStr = new SM2CipherText().i2dSM2CipherText(encryptedStr);
    let encryptedArray = new Uint8Array(buffer.from(hexStr, 'hex').buffer);
    return decryptByPrimalKeyArray(encryptedArray, priKey);
  }
  else {
    let base64Helper = new util.Base64Helper;
    let message = base64Helper.decodeSync(encryptedStr);
    return decryptByPrimalKeyArray(message, priKey);
  }
}

• 对密文格式进行转换：在[SM2CipherText.ets]点击asn.1按钮，调用密文转换函数实现对密文内容进行转换。 完成密文转换操作。

import { SM2Sequence } from './SM2Sequence';
import { hilog } from '@kit.PerformanceAnalysisKit';

export class ASN1Util {
  static readonly BOOLEAN: string = "01";
  static readonly INTEGER: string = "02";
  static readonly BIT_STRING: string = "03";
  static readonly OCTEN_STRING: string = "04";
  static readonly NULL: string = "05";
  static readonly REAL: string = "09";
  static readonly ENUMERATED: string = "0a";
  static readonly SEQUENCE: string = "30";
  static readonly SET: string = "31";
}

export class SM2CipherText {
  i2dSM2CipherText(primal_data: string): string {
    let sm2_sequence = new SM2Sequence();
    sm2_sequence.C1x = primal_data.slice(0, 64);
    primal_data = primal_data.slice(64, primal_data.length);
    sm2_sequence.C1y = primal_data.slice(0, 64);
    primal_data = primal_data.slice(64, primal_data.length);
    sm2_sequence.C3 = primal_data.slice(0, 64);
    primal_data = primal_data.slice(64, primal_data.length);
    sm2_sequence.C2 = primal_data;

    let C1x_title: string = (Number.parseInt("0x" + sm2_sequence.C1x.slice(0, 2)) > 127) ? "022100" : "0220";
    let C1y_title: string = (Number.parseInt("0x" + sm2_sequence.C1y.slice(0, 2)) > 127) ? "022100" : "0220";
    let C3_title: string = "0420";
    let C2_title: string = "04" + this.genLenHex(sm2_sequence.C2);
    let sequence_message: string = C1x_title + sm2_sequence.C1x + C1y_title + sm2_sequence.C1y + C3_title + sm2_sequence.C3 + C2_title + sm2_sequence.C2;
    let sequence_lenHex: string = this.genLenHex(sequence_message);

    let standard_data = "30" + sequence_lenHex + sequence_message;
    return standard_data;
  }

  d2iSM2CipherText(standard_data: string): string {
    let message: string = standard_data;
    if (!message.startsWith(ASN1Util.SEQUENCE)) {
      this.ciphertextErr();
    }
    message = message.slice(ASN1Util.SEQUENCE.length, message.length);

    let sequence_lexHex: string = this.getLenHex(message);
    message = message.slice(sequence_lexHex.length, message.length);
    let sequence_len: number = this.lenHex2number(sequence_lexHex);
    if (sequence_len != message.length / 2) {
      this.ciphertextErr();
    }

    let sm2_sequence = new SM2Sequence();
    message = this.readC1(sm2_sequence, message);
    message = this.readC3(sm2_sequence, message);
    message = this.readC2(sm2_sequence, message);
    console.log(sm2_sequence.toString());

    let primal_data: string = sm2_sequence.C1x + sm2_sequence.C1y + sm2_sequence.C3 + sm2_sequence.C2;
    return primal_data;
  }

  genLenHex(content: string): string {
    let size: number = content.length / 2;
    let lenHex: string;
    if (size.toString(16).length % 2 == 1) {
      lenHex = '0' + size.toString(16);
    } else {
      lenHex = size.toString(16);
    }

    if (size < 0x80) {
      return lenHex;
    }
    let lenHex_size: number = lenHex.length / 2;
    return (lenHex_size | 0x80).toString(16) + lenHex;
  }

  getLenHex(data: string): string {
    let byte: number = Number.parseInt("0x" + data.slice(0, 2));
    let len_size: number = byte > 127 ? byte - 0x80 + 1 : 1;
    return data.slice(0, len_size * 2);
  }

  lenHex2number(lenHex: string): number {
    if (lenHex.length == 2) {
      return Number.parseInt("0x" + lenHex);
    }
    return Number.parseInt("0x" + lenHex.slice(2, lenHex.length));
  }

  ciphertextErr() {
    hilog.error(0, "d2i_SM2_Ciphertext", "密文格式错误");
    throw new Error("SM2 ciphertext error!");
  }

  readC1(sm2_sequence: SM2Sequence, data:string): string {
    let xy: string[] = [];
    for (let i = 0; i < 2; i++) {
      if (data.startsWith("0220")) {
        xy[i] = data.slice(4, 68);
        data = data.slice(68, data.length);
      } else if (data.startsWith("022100")) {
        xy[i] = data.slice(6, 70);
        data = data.slice(70, data.length);
      } else {
        this.ciphertextErr();
      }
    }
    sm2_sequence.C1x = xy[0];
    sm2_sequence.C1y = xy[1];
    return data;
  }

  readC2(sm2_sequence: SM2Sequence, data:string): string {
    if (data.startsWith(ASN1Util.OCTEN_STRING)) {
      data = data.slice(ASN1Util.OCTEN_STRING.length, data.length);
      let C2_lenHex = this.getLenHex(data);
      data = data.slice(C2_lenHex.length, data.length);
      if (this.lenHex2number(C2_lenHex) != data.length / 2) {
        this.ciphertextErr();
      }
      sm2_sequence.C2 = data;
    }
    else {
      this.ciphertextErr();
    }
    return data;
  }

  readC3(sm2_sequence: SM2Sequence, data:string): string {
    if (data.startsWith("0420")) {
      sm2_sequence.C3 = data.slice(4, 68);
      data = data.slice(68, data.length);
    }
    else {
      this.ciphertextErr();
    }
    return data;
  }
}

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