# AES\_DECRYPT

## Syntax

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```sql
AES_ENCRYPT(crypt_str, key_str, [, iv [, mode]])
```

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```sql
AES_DECRYPT(crypt_str,key_str)
```

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## Description

This function allows decryption of data using the official AES (Advanced Encryption Standard) algorithm. For more information, see the description of [AES\_ENCRYPT()](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/encryption-hashing-and-compression-functions/aes_encrypt).

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The function supports an initialization vector, and control of the block encryption mode. The default mode is specified by the [block\_encryption\_mode](https://mariadb.com/docs/server/server-management/variables-and-modes/server-system-variables#block_encryption_mode) system variable, which can be changed when calling the function with a mode. *mode* is aes-{128,192,256}-{ecb,cbc,ctr} for example: "AES-128-cbc".

For modes that require it, the initialization\_vector *iv* should be 16 bytes (it can be longer, but the extra bytes are ignored). A shorter *iv*, where one is required, results in the function returning `NULL`. Calling [RANDOM\_BYTES(16)](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/encryption-hashing-and-compression-functions/random_bytes) will generate a random series of bytes that can be used for the *iv*.

**Examples**

```sql
SELECT HEX(AES_ENCRYPT('foo', 'bar', '0123456789abcdef', 'aes-128-ctr')) AS x; 
+--------+
| x      |
+--------+
| C57C4B |
+--------+


SELECT AES_DECRYPT(x'C57C4B', 'bar', '0123456789abcdef', 'aes-128-ctr'); 
+------------------------------------------------------------------+
| AES_DECRYPT(x'C57C4B', 'bar', '0123456789abcdef', 'aes-128-ctr') |
+------------------------------------------------------------------+
| foo                                                              |
+------------------------------------------------------------------+
```

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The function does **not** support an initialization vector.
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<sub>*This page is licensed: GPLv2, originally from*</sub> [<sub>*fill\_help\_tables.sql*</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

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