After restoring the database into a another server, I run the following T-SQL command:
OPEN MASTER KEY DECRYPTION BY PASSWORD = 'password'
ALTER MASTER KEY ADD ENCRYPTION BY SERVICE MASTER KEY
and when I try to open the SYMMETRIC key to retrieve the data on the encrypted field with a SELECT statement I get the following message (the same SELECT statement on the original server works fine as expected).
Msg 15466, Level 16, State 1, Line 1
An error occurred during decryption.
(402 row(s) affected)
Msg 15315, Level 16, State 1, Line 7
The key 'SymKey' is not open. Please open the key before using it.