--- title: "Cryptographic functions" canonical: "https://docs.cuesystem.com/space/CVCHELP/555909182/Cryptographic%20functions" format: markdown --- > Macro (toc) --- # CalculateMD5 This function calculates a 16 bytes MD5 value. A parameter destinationbytestring must be 16 bytes long at least. Read [more about MD5](http://en.wikipedia.org/wiki/MD5).  #### Syntax  ```visualbasic Function CalculateMD5(  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString)  As Boolean ``` #### Parameters* * sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data.  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination data, the MD5 value. It must be 16 bytes long at least.  #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function [GetLastError](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#GetLastError) returns the error number that occurred while executing the command. The errors that can happen: [120](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#120).  # CalculateSHA1 This function calculates a 20 bytes SHA1 value. A parameter destinationbytestring must be 20 bytes long at least.   #### Syntax  ```visualbasic Function CalculateSHA1(  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data.  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination data, the SHA1 value. It must be 20 bytes long at least.  #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function [GetLastError](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#GetLastError) returns the error number that occurred while executing the command. The errors that can happen: [120](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#120).   # CalculateSHA256 This function calculates a 32 bytes SHA2 256bits value. A parameter destinationbytestring must be 32 bytes long at least.  #### Syntax  ```visualbasic Function CalculateSHA256(  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data.  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination data, the SHA2 256bits value. It must be 32 bytes long at least.  #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function [GetLastError](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#GetLastError) returns the error number that occurred while executing the command. The errors that can happen: [120](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#120).  # CalculateSHA512 This function calculates a 64 bytes SHA2 512bits value. A parameter destinationbytestring must be 64 bytes long at least.    #### Syntax  ```visualbasic Function CalculateSHA512(  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data.  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination data, the SHA2 512bits value. It must be 64 bytes long at least.  #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function [GetLastError](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#GetLastError) returns the error number that occurred while executing the command. The errors that can happen: [120](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#120).  # DecryptAES128CBC This function decrypts data encrypted by the AES128 algorithm with Cipher Block Chaining (CBC) mode.  A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of CBC is at the link [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC))   > ℹ️ This function is supported since firmware 20.30 #### Syntax  ```visualbasic Function DecryptAES128CBC (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString,  ByRef encryptioniv  As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for encrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to 245.  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) is the encryption key for encryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  encryptioniv  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the initialization vector for encryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244). The value of the parameter is changed by function because of Cipher Block Chaining (CBC) algorithm.  ![image-20240118-093701.png](media://8f511d20-1bc6-461f-80b6-739643ec92fd) #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number. These errors can happen: [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244), [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  # DecryptAES256CBC This function decrypts data encrypted by the AES256 algorithm with Cipher Block Chaining (CBC) mode.  A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of CBC is at the link [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC))   #### Syntax  ```visualbasic Function DecryptAES256CBC (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString,  ByRef encryptioniv  As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for encrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to 245.  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) is the encryption key for encryption. Length must be 32 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  encryptioniv  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the initialization vector for encryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244). The value of the parameter is changed by function because of Cipher Block Chaining (CBC) algorithm.  ![image-20240118-093706.png](media://e754cbef-3f56-4016-b3d8-33fa69974851) #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number. These errors can happen: [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244), [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  # DecryptAES128ECB This function decrypts data encrypted by the AES128 algorithm with Electronic codebook (ECB) mode. > ℹ️ This function is supported since firmware 20.30 A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of ECB is at the lin [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB))   #### Syntax  ```visualbasic Function DecryptAES128ECB (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for encrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to 245.  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) is the encryption key for encryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  ![image-20240118-093033.png](media://e43ca80a-85e1-4582-8a3c-04c93776618a) #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number. These errors can happen: [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244) , [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  # DecryptAES256ECB This function decrypts data encrypted by the AES256 algorithm with Electronic codebook (ECB) mode. > ℹ️ This function is supported since firmware 20.30 A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of ECB is at the lin [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)) #### Syntax  ```visualbasic Function DecryptAES256ECB (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the source data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for encrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to 245.  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) is the encryption key for encryption. Length must be 32 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  ![image-20240118-093033.png](media://e43ca80a-85e1-4582-8a3c-04c93776618a) #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number. These errors can happen: [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244) , [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  # EncryptAES128CBC This function encrypts data by the AES128 algorithm with Cipher Block Chaining (CBC) mode.   > ℹ️ This function is supported since firmware 20.30 A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of CBC detailed the link [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC))   #### Syntax  ```visualbasic Function EncryptAES128CBC (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString,  ByRef encryptioniv  As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is encrypted data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for unencrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the encryption key for decryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  encryptioniv  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the initialization vector for decryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244). The value of the parameter is changed by function because of Cipher Block Chaining (CBC) algorithm.  ![image-20240118-093107.png](media://a400adb8-e26e-4c4b-ae14-086fcaf6efd5) #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number. These errors can happen: [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244), [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  # EncryptAES256CBC This function encrypts data by the AES256 algorithm with Cipher Block Chaining (CBC) mode.   A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of CBdetailed the link [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_block_chaining_(CBC))   #### Syntax  ```visualbasic Function EncryptAES256CBC (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString,  ByRef encryptioniv  As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is encrypted data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for unencrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the encryption key for decryption. Length must be 32 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  encryptioniv  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the initialization vector for decryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244). The value of the parameter is changed by function because of Cipher Block Chaining (CBC) algorithm.  ![image-20240118-093113.png](media://eff0fb89-c286-4f75-ae77-4daf26caea10) #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number. These errors can happen: [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244), [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  # EncryptAES128ECB This function encrypts data by the AES128 algorithm with Electronic codebook (ECB) mode. > ℹ️ This function is supported since firmware 20.30 A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of ECB is at the lin [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)) #### Syntax  ```visualbasic Function EncryptAES128ECB (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is encrypted data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for unencrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the encryption key for decryption. Length must be 16 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  ![image-20240118-093858.png](media://613141ff-25ef-4364-be6d-79e829955634) # EncryptAES256ECB This function encrypts data by the AES256 algorithm with Electronic codebook (ECB) mode. > ℹ️ This function is supported since firmware 20.30 A detailed description of AES is at the link [https://en.wikipedia.org/wiki/Advanced_Encryption_Standard](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)   A detailed description of ECB is at the lin [https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_codebook_(ECB)) #### Syntax  ```visualbasic Function EncryptAES256ECB (  sourcebytestring As ByteString,  ByRef destinationbytestring As ByteString,  encryptionkey As ByteString)  As Boolean ``` #### Parameters  sourcebytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is encrypted data. Actual length must be divided by 16 otherwise the function returns False and sets the last error to [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  destinationbytestring  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination buffer for unencrypted data. It must be as long as sourcebytestring at least otherwise the function returns False and sets the last error to [245](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#245).  encyptionkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the encryption key for decryption. Length must be 32 otherwise the function returns False and sets the last error to value [244](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#244).  ![image-20240118-093858.png](media://613141ff-25ef-4364-be6d-79e829955634) # HMAC_SHA256 The function generates a keyed hash value using the HMAC method [https://en.wikipedia.org/wiki/HMAC](https://en.wikipedia.org/wiki/HMAC) .  #### Syntax  ```visualbasic Function HMAC_SHA256 (  key As ByteString,  data As ByteString,  ByRef result As ByteString)  As Boolean ``` #### Parameters  key  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) Shared secret key used for generating the HMAC variant of the message digest  data  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString). Data to be hashed.  result  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the hashed value from input parameters. The declared length of this ByteString must be 32 bytes at least.    #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function GetLastError returns the error number.  # PBKDF2_HMAC_SHA256 The function provides PKCS#5 password-based key derivation function 2. It uses HMAC as a pseudorandom function. PBKDF2 is a key derivation function with a sliding computational cost, used to reduce vulnerabilities to brute force attacks [https://en.wikipedia.org/wiki/PBKDF2](https://en.wikipedia.org/wiki/PBKDF2) .    #### Syntax  ```visualbasic Function PBKDF2_HMAC_SHA256(  password As ByteString,  salt As ByteString,  iterations As Long,  ByRef derivedkey As ByteString,  Optional dklen As Long := 256)  As Boolean ``` #### Parameters  password  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the password.  salt  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is input random data. Salt should contain 16 bytes or more random bytes.  iterations  [Long](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Long). The number of iterations.  derivedkey  [ByteString](/wiki/spaces/CVCHELP/pages/495058958/Data+types#ByteString) It is the destination data. The declared length of this Bytestring must be the same or bigger than the number of required bits defined by dkLen parameter. Example: for dkLen 256 (bits) must be declared length of derivedkey 32 bytes at least.    dklen  [Long](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Long). Is the length of the required derived key in bits. For the SHA256 hash algorithm is it 256 (bits) by default.  #### Return value  [Boolean](/wiki/spaces/CVCHELP/pages/495058958/Data+types#Boolean) It is True on success or False if an error occurs. The function [GetLastError](/wiki/spaces/CVCHELP/pages/510525445/Command+errors#GetLastError) returns the error number that occurred while executing the command.