Pinning public key in my app

I am pinning public key in my app as part of security measures, for that I have extracted public key from my PEM certificate which looks like ``` -----BEGIN PUBLIC KEY----- MIIBIj....IDAQAB -----END PUBLIC KEY----- ``` However in sample code of OWASP, we do see code to compare DER encoded public key, ``` // DER encoded public key private static String PUB_KEY = "30820122300d06092a864886f70d0101" + "0105000382010f003082010a0282010100b35ea8adaf4cb6db86068a836f3c85" + "5a545b1f0cc8afb19e38213bac4d55c3f2f19df6dee82ead67f70a990131b6bc" + "ac1a9116acc883862f00593199df19ce027c8eaaae8e3121f7f329219464e657" + "2cbf66e8e229eac2992dd795c4f23df0fe72b6ceef457eba0b9029619e0395b8" + "609851849dd6214589a2ceba4f7a7dcceb7ab2a6b60c27c69317bd7ab2135f50" + "c6317e5dbfb9d1e55936e4109b7b911450c746fe0d5d07165b6b23ada7700b00" + "33238c858ad179a82459c4718019c111b4ef7be53e5972e06ca68a112406da38" + "cf60d2f4fda4d1cd52f1da9fd6104d91a34455cd7b328b02525320a35253147b" + "e0b7a5bc860966dc84f10d723ce7eed5430203010001"; ``` I know DER is a binary format, however not sure how author converted or extracted above format? when I convert into DER it is having raw bytes not like above format. Do anyone has pointer around this? Alternate approach can be, Sample code, ``` //Hack ahead: BigInteger and toString(). We know a DER encoded Public Key begins //with 0x30 (ASN.1 SEQUENCE and CONSTRUCTED), so there is no leading 0x00 to drop. RSAPublicKey pubkey = (RSAPublicKey) chain[0].getPublicKey(); String enc oded = new BigInteger(1 /* positive */, pubkey.getEncoded()).toString(16); ``` If I convert "encoded" variable base64 PEM public key format. How to do it in Android? Any help would be appreciated