468. (Android/Java) X.509 Certificate 인증서 정보를 base64 로 변경 및 base64 를 X509Certificate 인증서로 변경 실시

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[개발 환경 설정]

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개발 툴 : AndroidStudio

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[소스 코드]

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        // -------------------------------------
        // [로직 처리 실시]
        // -------------------------------------
        try {

            // [생성할 인증서 정보 및 유효 일자 정의 실시]
            String KEY_ALIAS = "PrivateKeyTwok";
            String AndroidKeyStore = "AndroidKeyStore";

            Calendar start = Calendar.getInstance();
            Calendar end = Calendar.getInstance();
            end.add(Calendar.YEAR, 20);


            // [AlgorithmParameterSpec 사용해 인증서 정보 정의]
            AlgorithmParameterSpec spec = null;
            if (Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M){
                spec = new KeyGenParameterSpec.Builder(KEY_ALIAS, KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
                        .setCertificateSubject(new X500Principal("CN=" + KEY_ALIAS + " CA Certificate"))
                        .setCertificateSerialNumber(BigInteger.ONE)
                        .setCertificateNotBefore(start.getTime())
                        .setCertificateNotAfter(end.getTime())
                        .setBlockModes(KeyProperties.BLOCK_MODE_ECB)
                        .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_RSA_PKCS1)
                        .build();
            }
            else {
                spec = new KeyPairGeneratorSpec.Builder(getApplicationContext())
                        .setAlias(KEY_ALIAS)
                        .setSubject(new X500Principal("CN=" + KEY_ALIAS + " CA Certificate"))
                        .setSerialNumber(BigInteger.ONE)
                        .setStartDate(start.getTime())
                        .setEndDate(end.getTime())
                        .build();
            }


            // [비대칭 암호화 새 개인 키 생성 및 KeyStore 에 저장 실시]
            KeyPairGenerator kpg = KeyPairGenerator.getInstance(KeyProperties.KEY_ALGORITHM_RSA, AndroidKeyStore);
            kpg.initialize(spec);
            KeyPair kp = kpg.generateKeyPair();


            // [Keystore 로드]
            KeyStore keyStore = KeyStore.getInstance(AndroidKeyStore);
            keyStore.load(null);


            // [인증서 로드 : X.509]
            Certificate originCertificate = keyStore.getCertificate(KEY_ALIAS);

            // -------------------------------------

            // [인증서 정보를 base64 로 변경 실시]
            StringBuffer base64Encode = new StringBuffer();
            base64Encode.append("-----BEGIN CERTIFICATE-----\n");
            base64Encode.append(Base64.encodeToString(originCertificate.getEncoded(), Base64.DEFAULT).trim());
            base64Encode.append("\n-----END CERTIFICATE-----");

            // -------------------------------------

            // [base64 데이터를 다시 인증서로 변경]
            String certData = base64Encode.toString();
            certData = certData.replaceAll("-----BEGIN CERTIFICATE-----", "");
            certData = certData.replaceAll("-----END CERTIFICATE-----", "");
            certData = certData.replaceAll(" ", "");

            byte encodedCert[] = Base64.decode(certData, Base64.DEFAULT);

            ByteArrayInputStream inputStream  =  new ByteArrayInputStream(encodedCert);

            CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
            X509Certificate convertCertificate = (X509Certificate)certFactory.generateCertificate(inputStream);

            // -------------------------------------

            // [로그 출력 실시]
            S_Log.ltd("================================================");
            S_Log.cnt("["+ACTIVITY_NAME+" >> "+C_Util.getNowMethod(1)+" :: 로그 출력 실시]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[keyStore isKeyEntry :: "+String.valueOf(keyStore.isKeyEntry(KEY_ALIAS))+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[originCertificate getType :: "+String.valueOf(originCertificate.getType())+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[originCertificate toString :: "+String.valueOf(originCertificate.toString())+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[base64Encode :: "+String.valueOf(base64Encode.toString())+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[certData :: "+String.valueOf(certData)+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[encodedCert :: "+String.valueOf(Arrays.toString(encodedCert))+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[convertCertificate getType :: "+String.valueOf(convertCertificate.getType())+"]");
            S_Log.cnt("----------------------------------------");
            S_Log.cnt("[convertCertificate toString :: "+String.valueOf(convertCertificate.toString())+"]");
            S_Log.lbd("================================================");

        }
        catch (Exception e){
            e.printStackTrace();
        }

 

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[결과 출력]

 

D///===========//: ================================================
I/: [A_Intro >> onCreate :: 로그 출력 실시]
I/: ----------------------------------------
I/: [keyStore isKeyEntry :: true]
I/: ----------------------------------------
I/: [originCertificate getType :: X.509]
I/: ----------------------------------------
I/: [originCertificate toString :: Certificate:
        Data:
            Version: 3 (0x2)
            Serial Number: 1 (0x1)
        Signature Algorithm: sha256WithRSAEncryption
            Issuer: CN=PrivateKeyTwok CA Certificate
            Validity
                Not Before: Jan 26 23:13:45 2023 GMT
                Not After : Jan 26 23:13:45 2043 GMT
            Subject: CN=PrivateKeyTwok CA Certificate
            Subject Public Key Info:
                Public Key Algorithm: rsaEncryption
                    Public-Key: (2048 bit)
                    Modulus:
                        00:a2:fa:82:65:d9:db:27:b7:93:36:b6:96:38:07:
                        ....
                        25:7d
                    Exponent: 65537 (0x10001)
            X509v3 extensions:
                X509v3 Key Usage: critical
                    Key Encipherment, Data Encipherment
        Signature Algorithm: sha256WithRSAEncryption
    ]
I/: ----------------------------------------
I/: [base64Encode :: -----BEGIN CERTIFICATE-----
    MIIB2zCCAcWgAwIBAgIBATANBgkqhkiG9w0BAQsFADAoMSYwJAYDVQQDEx1Qcml2YXRlS2V5VHdv
    ayBDQSBDZXJ0aWZpY2F0ZTAeFw0yMzAxMjYyMzEzNDVaFw00MzAxMjYyMzEzNDVaMCgxJjAkBgNV
    BAMTHVByaXZhdGVLZXlUd29rIENBIENlcnRpZmljYXRlMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8A
    BAMCBDAwDQYJKoZIhvcNAQELBQADAQA=
    -----END CERTIFICATE-----]
I/: ----------------------------------------
I/: [certData :: 
    MIIB2zCCAcWgAwIBAgIBATANBgkqhkiG9w0BAQsFADAoMSYwJAYDVQQDEx1Qcml2YXRlS2V5VHdv
    ayBDQSBDZXJ0aWZpY2F0ZTAeFw0yMzAxMjYyMzEzNDVaFw00MzAxMjYyMzEzNDVaMCgxJjAkBgNV
    BAMTHVByaXZhdGVLZXlUd29rIENBIENlcnRpZmljYXRlMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8A
    BAMCBDAwDQYJKoZIhvcNAQELBQADAQA=
    ]
I/: ----------------------------------------
I/: [encodedCert :: [48, -126, 1, -37, 48, -126, 1, -59, -96, 3, 2, 1, 2, 2, 1, 1, 48, 13, 6, 9, 42, -122, 72, ....... , 4, 48, 48, 13, 6, 9, 42, -122, 72, -122, -9, 13, 1, 1, 11, 5, 0, 3, 1, 0]]
I/: ----------------------------------------
I/: [convertCertificate getType :: X.509]
I/: ----------------------------------------
I/: [convertCertificate toString :: Certificate:
        Data:
            Version: 3 (0x2)
            Serial Number: 1 (0x1)
        Signature Algorithm: sha256WithRSAEncryption
            Issuer: CN=PrivateKeyTwok CA Certificate
            Validity
                Not Before: Jan 26 23:13:45 2023 GMT
                Not After : Jan 26 23:13:45 2043 GMT
            Subject: CN=PrivateKeyTwok CA Certificate
            Subject Public Key Info:
                Public Key Algorithm: rsaEncryption
                    Public-Key: (2048 bit)
                    Modulus:
                        00:a2:fa:82:65:d9:db:27:b7:93:36:b6:96:38:07:
                        ....
                        25:7d
                    Exponent: 65537 (0x10001)
            X509v3 extensions:
                X509v3 Key Usage: critical
                    Key Encipherment, Data Encipherment
        Signature Algorithm: sha256WithRSAEncryption
    ]
D///===========//: ================================================

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