Merge "Unbreak obtaining symmetric keys from AndroidKeyStore."

import java.util.Enumeration;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.Set;

import javax.crypto.SecretKey;

                throw new UnrecoverableKeyException("Key algorithm unknown");

            }

            int keymasterDigest =

                    keyCharacteristics.hwEnforced.getInt(KeymasterDefs.KM_TAG_DIGEST, -1);

            if (keymasterDigest == -1) {

                keymasterDigest =

                        keyCharacteristics.swEnforced.getInt(KeymasterDefs.KM_TAG_DIGEST, -1);

            List<Integer> keymasterDigests =

                    keyCharacteristics.getInts(KeymasterDefs.KM_TAG_DIGEST);

            int keymasterDigest;

            if (keymasterDigests.isEmpty()) {

                keymasterDigest = -1;

            } else {

                // More than one digest can be permitted for this key. Use the first one to form the

                // JCA key algorithm name.

                keymasterDigest = keymasterDigests.get(0);

            }

            String keyAlgorithmString;