SELECT
           SK.name,
           SK.key_length,
           SK.algorithm_desc,
           [DECRYPTBYCERT(C.certificate_id, KE.crypt_property)] = DECRYPTBYCERT(C.certificate_id, KE.crypt_property),
           SK.key_guid
FROM       sys.symmetric_keys SK
INNER JOIN sys.key_encryptions KE ON KE.key_id = SK.symmetric_key_id
INNER JOIN sys.certificates C ON C.thumbprint = KE.thumbprint
WHERE      KE.crypt_type = 'EPUC'

CREATE SYMMETRIC KEY TestKey
WITH
    ALGORITHM = AES_256,
    KEY_SOURCE = 'password to derive key',
    IDENTITY_VALUE = 'password to derive guid'
ENCRYPTION BY CERTIFICATE TestCert;