SQL Server中可以通过使用内置的加密函数和算法来进行数据加密和解密。以下是一些常用的方法：

使用内置的加密函数：

示例代码：

-- 加密数据DECLARE @input VARCHAR(100) = 'Sensitive data'DECLARE @password VARCHAR(100) = 'MySecretPassword'DECLARE @encrypted VARBINARY(MAX)SET @encrypted = ENCRYPTBYPASSPHRASE(@password, @input)SELECT @encrypted AS EncryptedData-- 解密数据DECLARE @decrypted VARCHAR(100)SET @decrypted = CAST(DECRYPTBYPASSPHRASE(@password, @encrypted) AS VARCHAR(100))SELECT @decrypted AS DecryptedData

使用对称加密算法：SQL Server还支持对称加密算法，可以使用以下函数进行数据加密和解密：

示例代码：

-- 创建对称密钥CREATE SYMMETRIC KEY MySymmetricKeyWITH ALGORITHM = AES_256ENCRYPTION BY PASSWORD = 'MySecretPassword'-- 加密数据DECLARE @input VARCHAR(100) = 'Sensitive data'DECLARE @encrypted VARBINARY(MAX)OPEN SYMMETRIC KEY MySymmetricKeySET @encrypted = ENCRYPTBYKEY(KEY_GUID('MySymmetricKey'), @input)SELECT @encrypted AS EncryptedDataCLOSE SYMMETRIC KEY MySymmetricKey-- 解密数据DECLARE @decrypted VARCHAR(100)OPEN SYMMETRIC KEY MySymmetricKeySET @decrypted = CAST(DECRYPTBYKEY(@encrypted) AS VARCHAR(100))SELECT @decrypted AS DecryptedDataCLOSE SYMMETRIC KEY MySymmetricKey

需要注意的是，加密和解密过程中需要保护好密钥和密码，确保数据的安全性。