Android get App SHA256 fingerprint

androidcertificate_fingerprint.java

  /**
   * Get SHA256 from PackageManager / PackageInfo / Signatures
   */
  fun printSignature() {
        val packageManager: PackageManager = CONTEXT.getPackageManager()
        val signature: Array<Signature> = packageManager.getPackageInfo("YOUR PACKAGE_NAME, LIKE com.xx.yy.zz", PackageManager.GET_SIGNATURES).signatures

        signature.asIterable().forEach {
            Log.i("SHA256", getFingerprint(it))
        }
    }

    /**
     * Get fingerprint from a certificate in android.content.pm.Signature
     * @return String fingerprint that contains the SHA-256 digest
     */
    private fun getFingerprint(ce: Signature): String? {
        var certificate = ""
        val input: InputStream = ByteArrayInputStream(ce.toByteArray())
        var cf: CertificateFactory? = null
        try {
            cf = CertificateFactory.getInstance("X509")
        } catch (e: CertificateException) {
            e.printStackTrace()
        }
        var c: X509Certificate? = null
        try {
            if (cf != null) {
                c = cf.generateCertificate(input) as X509Certificate
            }
        } catch (e: CertificateException) {
            e.printStackTrace()
        }
        try {
            val md: MessageDigest = MessageDigest.getInstance("SHA-256")
            var publicKey = ByteArray(0)
            if (c != null) {
                publicKey = md.digest(c.encoded)
            }
            val hexString = StringBuilder()
            for (aPublicKeybyte in publicKey) {
                val appendString = Integer.toHexString(0xFF and aPublicKeybyte.toInt())
                if (appendString.length == 1) hexString.append("0")
                hexString.append(appendString)
            }
            certificate = hexString.toString()
        } catch (e1: NoSuchAlgorithmException) {
            e1.printStackTrace()
        } catch (e1: CertificateEncodingException) {
            e1.printStackTrace()
        }
        return certificate
    }