Could not validate certificate signature?

Question

I use the SSL Socket and Trustmanager from this side Self signed SSL

but i keep getting following error:

09-28 19:52:41.942: WARN/System.err(1

Answer 1

Check the time of your device, correct it and then check again.

Answer 2

In my case a following error raised on Android 4 and 5:

Caused by: com.android.org.bouncycastle.jce.exception.ExtCertPathValidatorException: Could not validate certificate: Certificate expired at Sat May 30 10:48:38 GMT+00:00 2020 (compared to Thu Aug 13 11:47:00 GMT+00:00 2020)

...

Caused by: java.security.cert.CertificateExpiredException: Certificate expired at Sat May 30 10:48:38 GMT+00:00 2020 (compared to Thu Aug 13 11:47:00 GMT+00:00 2020)

The server has certificate error (probably expired).

For Retrofit see https://stackoverflow.com/a/60507560/2914140. If you use Fuel as a REST library, see kotlin library that can do httpS connection without certificate verification (like curl --insecure).

You can trust all certificates, but it's dangerous.

import java.security.SecureRandom
import java.security.cert.X509Certificate
import javax.net.ssl.*
import javax.security.cert.CertificateException

companion object {

    private val gson: Gson
    private val retrofit: Retrofit

    init {

        val okHttpClient = getOkHttpBuilder().build()

        gson = GsonBuilder().setLenient().create()

        retrofit = Retrofit.Builder()
            .baseUrl(BASE_URL)
            .client(okHttpClient)
            .addConverterFactory(GsonConverterFactory.create(gson))
            .build()
    }

    private fun getOkHttpBuilder(): OkHttpClient.Builder =
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            OkHttpClient().newBuilder()
        } else {
            getUnsafeOkHttpClient()
        }

    private fun getUnsafeOkHttpClient(): OkHttpClient.Builder =
        try {
            // Create a trust manager that does not validate certificate chains
            val trustAllCerts: Array<TrustManager> = arrayOf(
                object : X509TrustManager {
                    @Throws(CertificateException::class)
                    override fun checkClientTrusted(chain: Array<X509Certificate?>?,
                                                    authType: String?) = Unit

                    @Throws(CertificateException::class)
                    override fun checkServerTrusted(chain: Array<X509Certificate?>?,
                                                    authType: String?) = Unit

                    override fun getAcceptedIssuers(): Array<X509Certificate> = arrayOf()
                }
            )
            // Install the all-trusting trust manager
            val sslContext: SSLContext = SSLContext.getInstance("SSL")
            sslContext.init(null, trustAllCerts, SecureRandom())
            // Create an ssl socket factory with our all-trusting manager
            val sslSocketFactory: SSLSocketFactory = sslContext.socketFactory
            val builder = OkHttpClient.Builder()
            builder.sslSocketFactory(sslSocketFactory,
                trustAllCerts[0] as X509TrustManager)
            builder.hostnameVerifier { _, _ -> true }
            builder
        } catch (e: Exception) {
            throw RuntimeException(e)
        }
}

See also https://stackoverflow.com/a/60507560/2914140 for Android version check and Glide connection.

Answer 3

BTW，we could re-produce this error easily -- just change the date of the phone to several years later.

NOTE: the error might be a little difference in different phone. Some might show that the certificate has expired.

Answer 4

Most probably server returned certificate chain with authorities you do not trust. (means: authority certificates are not known to your device as trusted) Solution: carefully examine certificates coming from HTTPS website, and add respective authorities to your truststore - but this part seems to be tricky

( here some explanations : http://groups.google.com/group/android-security-discuss/browse_thread/thread/0bf726de4f5275a3/391b900631d7f358 )

Answer 5

As Michael Levy mentioned, the reason I was getting this exception is that I had left my Android Emulator open for a few days and the clock had gotten pretty far out of sync. Once I restarted the emulator, the exception went away.