android ecdsa secp256k1 signature

I need an android app where you enter an ECDSA Secp256k1 private key and use it to sign a string.

Maybe using bouncycastle library.

The signature should be verifiable in php, using:

$data='teststring';

$pkey=openssl_pkey_get_public($public_key);

$res=openssl_verify($data,$signature,$pkey,OPENSSL_ALGO_SHA256);

Example public/private key pair:

-----BEGIN PUBLIC KEY-----

MFYwEAYHKoZIzj0CAQYFK4EEAAoDQgAEPfs0WCAFryKbEAOU5ScUqMm9iFmDEMi1

h2iEG5f3D/y+SrT3Q2pwyIXApphW82nZTs0wv9vzghqjA0zrsbIVJQ==

-----END PUBLIC KEY-----

-----BEGIN EC PRIVATE KEY-----

MIIBCwIBAQQgJ6TxAzr3IXM5u5M16+smwl/oDSpe3ycrWv7MgPfUyvqggeMwgeAC

AQEwLAYHKoZIzj0BAQIhAP////////////////////////////////////7///wv

MEQEIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABCAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAABwRBBHm+Zn753LusVaBilc6HCwcCm/zbLc4o

2VnygVsW+BeYSDradyajxGVdpPv8DhEIqP0XtEimhVQZnEfQj/sQ1LgCIQD/////

///////////////+uq7c5q9IoDu/0l6M0DZBQQIBAQ==

-----END EC PRIVATE KEY-----

Android Java Desarrollo de apps móviles PHP Arquitectura de software

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