# Android 7.0 can't establish ssl connection

**URL:** <https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050>\
**Category:** Help\
**Created:** [May 19, 2021, 1:46pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050 "2021-05-19T13:46:02Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![rnz](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rnz/32/40044_2.png) [@rnz](https://community.letsencrypt.org/u/rnz)\
**Post date:** [May 19, 2021, 1:46pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/1 "2021-05-19T13:46:02Z")

</div>

My domain is: [starline.ru](http://starline.ru)

I ran this command: android 7.0 can't connect

It produced this output:

```nohighlight
Caused by: javax.net.ssl.SSLProtocolException: SSL handshake terminated: ssl=0x76a8eb8a00: Failure in SSL library, usually a protocol error error:10000410:SSL routines:OPENSSL_internal:SSLV3_ALERT_HANDSHAKE_FAILURE (external/boringssl/src/ssl/s3_pkt.c:641 0x76a8e2b0a0:0x00000001) error:1000009a:SSL routines:OPENSSL_internal:HANDSHAKE_FAILURE_ON_CLIENT_HELLO (external/boringssl/src/ssl/s3_clnt.c:800 0x76d2e2c253:0x00000000)
at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)
at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:364)

```

SSLV3 - wrapper string, actualy sslv3 not use

My web server is (include version):

```nohighlight
nginx version: nginx/1.14.1
built with OpenSSL 1.1.0f 25 May 2017 (running with OpenSSL 1.1.0l 10 Sep 2019)
TLS SNI support enabled

```

The operating system my web server runs on is (include version): `Debian GNU/Linux 9.13 (stretch)`

Previously, the RSA private key was generated. And everything worked.  
Now a private key has been generated as EC and application (with okhttp3 [https://square.github.io/okhttp](https://square.github.io/okhttp) or direct use ssl) on Android 7.0 - cannot connect (application using android webclient backend is working).

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<div class="post-metadata">

**Author:** ![Nummer378](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/nummer378/32/49862_2.png) [@Nummer378](https://community.letsencrypt.org/u/Nummer378)\
**Post date:** [May 19, 2021, 1:53pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/2 "2021-05-19T13:53:21Z")

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You're almost certainly running into this issue:

> [@Any info on the upcoming ECDSA certificate chain with Android Compatibility](https://community.letsencrypt.org/t/any-info-on-the-upcoming-ecdsa-certificate-chain-with-android-compatibility/149613/3):
>
> W…

The only way to fix this is by NOT using an EC certificate. Right now you can work around by switching to P-256, but as the future E1 intermediate is P-384, that's not a long term solution.

---

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**Author:** ![petercooperjr](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/petercooperjr/32/84698_2.png) [@petercooperjr](https://community.letsencrypt.org/u/petercooperjr)\
**Post date:** [May 19, 2021, 1:54pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/3 "2021-05-19T13:54:35Z")

</div>

That server is using a P-384, elliptic curve certificate, which Android 7.0 doesn't support.

As least according to @Nummer378 in [another thread](https://community.letsencrypt.org/t/any-info-on-the-upcoming-ecdsa-certificate-chain-with-android-compatibility/149613/3):

> [Android 7.0 has a bug, where the only supported elliptic curve is P-256](https://issuetracker.google.com/issues/37122132), meaning that the P-384 curve used by Let's Encrypts E1/X2 certs cannot be handled by this Android version. The Android version advises ECC support though, so I presume that this scenario will simply break (handshakes usually fail with "illegal parameter" TLS alert from my tests). 7.1 is fixed though, this seems to only affect 7.0. Older than 7.0 (e.g 6.x and below) as well as 7.1 and newer works fine.

So you need to use the P-256 elliptic curve (at least as long as it's still signed by the RSA intermediate, as that is supposed to change eventually to be signed by a P-384 intermediate that will break on Android 7.0 anyway), so stick with RSA if you need to support older android versions.

(And once again, @Nummer378 is faster than I.)

---

<div class="post-metadata">

**Author:** ![rnz](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rnz/32/40044_2.png) [@rnz](https://community.letsencrypt.org/u/rnz)\
**Post date:** [May 19, 2021, 1:55pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/4 "2021-05-19T13:55:37Z")

</div>

> The only way to fix this is by NOT using an EC certificate.

How I can generate RSA instead EC?

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<div class="post-metadata">

**Author:** ![petercooperjr](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/petercooperjr/32/84698_2.png) [@petercooperjr](https://community.letsencrypt.org/u/petercooperjr)\
**Post date:** [May 19, 2021, 1:56pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/5 "2021-05-19T13:56:41Z")

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Well, how do you get your certificate for the server? Or are you just in control of the client but not the server?

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<div class="post-metadata">

**Author:** ![rnz](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rnz/32/40044_2.png) [@rnz](https://community.letsencrypt.org/u/rnz)\
**Post date:** [May 19, 2021, 1:59pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/6 "2021-05-19T13:59:00Z")

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I control servers. Problem have on clients after planned update lets encrypt certs on servers.  
Current setting on nginx:

```nohighlight
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

# ssl_ecdh_curve prime256v1:secp384r1;
# ssl_ecdh_curve prime256v1;
# ssl_ecdh_curve X25519:P-256:P-384:P-224:P-521;
        ssl_ecdh_curve P-256;

```

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<div class="post-metadata">

**Author:** ![petercooperjr](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/petercooperjr/32/84698_2.png) [@petercooperjr](https://community.letsencrypt.org/u/petercooperjr)\
**Post date:** [May 19, 2021, 2:18pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/7 "2021-05-19T14:18:12Z")

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So, you need to configure whatever ACME client you're using to generate an RSA key instead of an EC one. It's still not clear to me what ACME client you're using. Most of them will use RSA by default and wouldn't switch to EC without somebody specifically telling them to.

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<div class="post-metadata">

**Author:** ![rnz](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rnz/32/40044_2.png) [@rnz](https://community.letsencrypt.org/u/rnz)\
**Post date:** [May 19, 2021, 2:37pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/8 "2021-05-19T14:37:21Z")

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Thank you! I use dehydrate script - it have  
`--algo (-a) rsa|prime256v1|secp384r1 Which public key algorithm should be used? Supported: rsa, prime256v1 and secp384r1`  
Now I will try to generate new certs.

I generate new certs with prime256v1 - now Android 7.0 is work.  
Thanks all!

---

<div class="post-metadata">

**Author:** ![petercooperjr](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/petercooperjr/32/84698_2.png) [@petercooperjr](https://community.letsencrypt.org/u/petercooperjr)\
**Post date:** [May 19, 2021, 2:59pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/9 "2021-05-19T14:59:22Z")

</div>

Glad to hear that's working for you. But do be aware that some other old systems might not support prime256v1 either, and you might need to switch to RSA. And at some point (possibly quite a while from now so old Android may not have as much market share), prime256v1 (P-256) keys will be signed by a P-384 intermediate, which Android 7.0 also won't like. RSA is the most backward-compatible, if that's something you're concerned with.

---

<div class="post-metadata">

**Author:** ![rnz](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rnz/32/40044_2.png) [@rnz](https://community.letsencrypt.org/u/rnz)\
**Post date:** [May 19, 2021, 5:19pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/10 "2021-05-19T17:19:48Z")

</div>

Once again I regenerated the certificate with the RSA, since ApplePay also had problems.

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<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/letsencrypt/original/3X/c/a/ca6c06ea1ea201324bba7048c6841ce60236468d.png) [@system](https://community.letsencrypt.org/u/system)\
**Post date:** [June 18, 2021, 5:20pm UTC](https://community.letsencrypt.org/t/android-7-0-cant-establish-ssl-connection/152050/11 "2021-06-18T17:20:05Z")

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Closed on June 18, 2021, 5:20pm UTC

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