ChaCha Class
Properties Methods Events Config Settings Errors
The ChaCha class can be used to encrypt and decrypt data with the ChaCha20 algorithm.
Syntax
ipworksencrypt.Chacha
Remarks
The class implements ChaCha20 as defined in RFC 7539. This may be used to both encrypt and decrypt data. The class also support Authenticated Encryption with Additional Data (AEAD) via AEAD_CHACHA20_POLY1305. To enable the use of AEAD set UseAEAD to True.
Data may be encrypted and decrypted in its entirety by calling Encrypt and Decrypt or chunk by chunk by calling EncryptBlock and DecryptBlock.
In all operations a Key and IV must be used. If IV is not set one is automatically generated. KeyPassword may be set in order to automatically generate both a Key and IV when a method is called. The same KeyPassword, or Key and IV pair are used on both sides of the operation data can be encrypted and decrypted.
Encrypt Notes
Encrypt will encrypt the specified data. The following properties are applicable:
- IV (required)
- Key (required)
- UseAEAD (optional)
- AdditionalAuthData (optional - applicable if UseAEAD is True);
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
Additional Notes
The Key property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If KeyPassword is set both Key and IV will be automatically generated when Encrypt is called.
The IV should typically be set to a 96 bit (12 byte) value. See the IV property for details on using a 64 bit (8 byte) value. If IV is not set a 96 bit (12 byte) value will automatically be generated by the class when Encrypt is called.
InitialCounter may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.
During encryption the Progress event will fire as data is encrypted.
Encrypt Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[]{ 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();
//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes.
// {0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76}
AEAD Notes
When encrypting and UseAEAD is True AdditionalAuthData optionally holds data that is authenticated but not encrypted.
After encrypting the message the AuthTag property will be populated. To include the AuthTag in the output set IncludeAuthTag to True.
Encrypt with AEAD Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();
//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes:
// {0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65}
//chacha.AuthTagB contains the byte[] of the AuthTag. The above code produces the following authentication tag:
// {0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78}
Encrypt Block Notes
EncryptBlock will encrypt the input data and return the encrypted block. The encrypted block will always be the same length as the decrypted data. The following properties are applicable:
InputBuffer specifies the input data to encrypt.
LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the class will calculate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.
EncryptBlock Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
byte[] tempEncryptedBlock;
//Encrypt any number of blocks of any size
tempEncryptedBlock = chacha.EncryptBlock(part1, false);
tempEncryptedBlock = chacha.EncryptBlock(part2, false);
//Pass true for the last block
tempEncryptedBlock = chacha.EncryptBlock(part3, true);
//Save AuthTag for use when decrypting
byte[] authTab = chacha.AuthTagB;
Decrypt Notes
Decrypt will decrypt the specified data. The following properties are applicable:
- IV (required)
- Key (required)
- UseAEAD (optional)
- AuthTag (conditional - required if UseAEAD is True)
- AdditionalAuthData (optional - applicable if UseAEAD is True);
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
Additional Notes
The Key property must be set to the 256 bit (32 byte) value originally used to encrypt the data. IV must be set to the original IV value used to encrypt the data.
If using a password, KeyPassword must be set to the same KeyPassword used when encrypting the data. This will automatically generate both Key and IV when Decrypt is called.
InitialCounter may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.
During decryption the Progress event will fire as data is decrypted.
Decrypt Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessageB = new byte[] { 0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76 };
chacha.Decrypt();
Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
AEAD Notes
When decrypting AdditionalAuthData must be set to the same value that was specified when encrypting. AuthTag must be set to the AuthTag value produced when encrypting.
Note: IncludeAuthTag may be set to True if the AuthTag value was included in the encrypted message.
Decrypt with AEAD Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.AuthTagB = new byte[] { 0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78 };
chacha.InputMessageB = new byte[] { 0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65 };
chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.Decrypt();
Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
Decrypt Block Notes
DecryptBlock will decrypt the input data and return the decrypted block. The decrypted block will always be the same length as the encrypted data. The following properties are applicable:
InputBuffer specifies the input data to decrypt.
LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the class will validate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.
DecryptBlock Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
cahcha.AuthTagB = authTag; //Value calculated during encryption.
byte[] tempDecryptedBlock;
//Decrypt any number of blocks of any size
tempDecryptedBlock = chacha.DecryptBlock(part1, false);
tempDecryptedBlock = chacha.DecryptBlock(part2, false);
//Pass true for the last block
tempDecryptedBlock = chacha.DecryptBlock(part3, true);
Property List
The following is the full list of the properties of the class with short descriptions. Click on the links for further details.
| AdditionalAuthData | Additional Authentication Data (AAD) used when UseAEAD is True. |
| AuthTag | The authentication tag used when UseAEAD is set to True. |
| InputFile | The file to process. |
| InputMessage | The message to process. |
| IV | The initialization vector (IV). |
| Key | The secret key for the symmetric algorithm. |
| KeyPassword | A password to generate the Key and IV . |
| OutputFile | The output file when encrypting or decrypting. |
| OutputMessage | The output message after processing. |
| Overwrite | Indicates whether or not the class should overwrite files. |
| UseAEAD | Whether to use AEAD (Authenticated Encryption with Additional Data). |
| UseHex | Whether input or output is hex encoded. |
Method List
The following is the full list of the methods of the class with short descriptions. Click on the links for further details.
| Config | Sets or retrieves a configuration setting. |
| Decrypt | Decrypts the data. |
| DecryptBlock | Decrypts a block and returns the decrypted data. |
| Encrypt | Encrypts the data. |
| EncryptBlock | Encrypts data and returns the encrypted block. |
| Reset | Resets the class. |
| SetInputStream | Sets the stream from which the class will read data to encrypt or decrypt. |
| SetOutputStream | Sets the stream to which the class will write encrypted or decrypted data. |
Event List
The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.
Config Settings
The following is a list of config settings for the class with short descriptions. Click on the links for further details.
| CloseInputStreamAfterProcessing | Determines whether or not the input stream is closed after processing. |
| CloseOutputStreamAfterProcessing | Determines whether or not the output stream is closed after processing. |
| EncryptedDataEncoding | The encoding of the encrypted input or output data. |
| IncludeAuthTag | Whether to append the authentication tag to the cipher text when UseAEAD is True. |
| IncludeIV | Whether to prepend the IV to the output data and read the IV from the input data. |
| InitialCounter | The initial counter value. |
| IVLength | The IV length in bytes. |
| KeyPasswordAlgorithm | The hash algorithm used to derive the Key and IV from the KeyPassword property. |
| KeyPasswordIterations | The number of iterations performed when using KeyPassword to derive the Key and IV. |
| KeyPasswordSalt | The salt value used in conjunction with the KeyPassword to derive the Key and IV. |
| BuildInfo | Information about the product's build. |
| GUIAvailable | Tells the class whether or not a message loop is available for processing events. |
| LicenseInfo | Information about the current license. |
| MaskSensitive | Whether sensitive data is masked in log messages. |
| UseDaemonThreads | Whether threads created by the class are daemon threads. |
| UseInternalSecurityAPI | Tells the class whether or not to use the system security libraries or an internal implementation. |
AdditionalAuthData Property (ChaCha Class)
Additional Authentication Data (AAD) used when UseAEAD is True.
Syntax
public byte[] getAdditionalAuthData(); public void setAdditionalAuthData(byte[] additionalAuthData);
Default Value
""
Remarks
This property specifies data that is authentication but not encrypted. This is only applicable when UseAEAD is True.
Note that AAD data is authenticated but not encrypted, so it is not included in the output.
AuthTag Property (ChaCha Class)
The authentication tag used when UseAEAD is set to True.
Syntax
public byte[] getAuthTag(); public void setAuthTag(byte[] authTag);
Default Value
""
Remarks
This property holds the 128 bit authentication tag used when UseAEAD is set to True. It is only applicable when UseAEAD is True.
This is populated after calling Encrypt. To also include the value in the output set IncludeAuthTag to True.
This must be set before calling Decrypt. If the auth tag is included in the encrypted data set IncludeAuthTag to True before calling Decrypt.
InputFile Property (ChaCha Class)
The file to process.
Syntax
public String getInputFile(); public void setInputFile(String inputFile);
Default Value
""
Remarks
This property specifies the file to be processed. Set this property to the full or relative path to the file which will be processed.
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
- SetInputStream
- InputFile
- InputMessage
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
InputMessage Property (ChaCha Class)
The message to process.
Syntax
public byte[] getInputMessage(); public void setInputMessage(byte[] inputMessage);
Default Value
""
Remarks
This property specifies the message to be processed.
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
- SetInputStream
- InputFile
- InputMessage
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
IV Property (ChaCha Class)
The initialization vector (IV).
Syntax
public byte[] getIV(); public void setIV(byte[] IV);
Default Value
""
Remarks
This property specifies the initialization vector (IV). This is also referred to as the nonce. By default this property is empty and the class will automatically generate a new IV value if KeyPassword or Key is set before Encrypt or EncryptBlock is called.
The size of the IV may be either 96 bits in length (12 bytes) or 64 bits in length (8 bytes).
Compatibility Notes
A 96 bit length value is used for implementations implementing RFC 7539. A 64 bit length value may be used by implementations that follow the original draft of ChaCha. When using a 96 bit length value the maximum file size of data is 256 GB.
If another entity is performing the decryption and it is not known whether it supports 64 bit length values, choose a 96 bit length value by default. This follows the RFC and should be the most widely implemented value.
The class supports both lengths.
Note: If Key is specified but IV is not, an IV will be automatically generated. To control the length of the IV that is generated set IVLength.
Key Property (ChaCha Class)
The secret key for the symmetric algorithm.
Syntax
public byte[] getKey(); public void setKey(byte[] key);
Default Value
""
Remarks
This secret key is used both for encryption and decryption. The secret key should be known only to the sender and the receiver. This key must be 256 bits in length (32 bytes).
If this property is left empty and KeyPassword is specified, a Key value will be generated by the class as necessary.
KeyPassword Property (ChaCha Class)
A password to generate the Key and IV .
Syntax
public String getKeyPassword(); public void setKeyPassword(String keyPassword);
Default Value
""
Remarks
When this property is set the class will calculate values for Key and IV using the PKCS5 password digest algorithm. This provides a simpler alternative to creating and managing Key and IV values directly.
OutputFile Property (ChaCha Class)
The output file when encrypting or decrypting.
Syntax
public String getOutputFile(); public void setOutputFile(String outputFile);
Default Value
""
Remarks
This property specifies the file to which the output will be written when Encrypt or Decrypt is called. This may be set to an absolute or relative path.
This property is only applicable to Encrypt and Decrypt.
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
OutputMessage Property (ChaCha Class)
The output message after processing.
Syntax
public byte[] getOutputMessage();
Default Value
""
Remarks
This property will be populated with the output from the operation if OutputFile and SetOutputStream are not set.
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
This property is read-only and not available at design time.
Overwrite Property (ChaCha Class)
Indicates whether or not the class should overwrite files.
Syntax
public boolean isOverwrite(); public void setOverwrite(boolean overwrite);
Default Value
False
Remarks
This property indicates whether or not the class will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.
UseAEAD Property (ChaCha Class)
Whether to use AEAD (Authenticated Encryption with Additional Data).
Syntax
public boolean isUseAEAD(); public void setUseAEAD(boolean useAEAD);
Default Value
False
Remarks
If this property is set to True the class uses the algorithm AEAD_CHACHA20_POLY1305 as defined in RFC 7539 to construct a message using AEAD. See Encrypt and Decrypt for details.
UseHex Property (ChaCha Class)
Whether input or output is hex encoded.
Syntax
public boolean isUseHex(); public void setUseHex(boolean useHex);
Default Value
False
Remarks
This property specifies whether the encrypted data is hex encoded.
If set to True, when Encrypt is called the class will perform the encryption as normal and then hex encode the output. OutputMessage or OutputFile will hold hex encoded data.
If set to True, when Decrypt is called the class will expect InputMessage or InputFile to hold hex encoded data. The class will then hex decode the data and perform decryption as normal.
AEAD Notes
When UseAEAD is set to True this property also applies to AuthTag. After calling Encrypt AuthTag will hold a hex encoded value. Before calling Decrypt AuthTag must be set to a hex encoded value.
Config Method (Chacha Class)
Sets or retrieves a configuration setting.
Syntax
public String config(String configurationString);
Remarks
Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.
These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.
To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).
To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.
Decrypt Method (Chacha Class)
Decrypts the data.
Syntax
public void decrypt();
Remarks
Decrypt will decrypt the specified data. The following properties are applicable:
- IV (required)
- Key (required)
- UseAEAD (optional)
- AuthTag (conditional - required if UseAEAD is True)
- AdditionalAuthData (optional - applicable if UseAEAD is True);
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
Additional Notes
The Key property must be set to the 256 bit (32 byte) value originally used to encrypt the data. IV must be set to the original IV value used to encrypt the data.
If using a password, KeyPassword must be set to the same KeyPassword used when encrypting the data. This will automatically generate both Key and IV when Decrypt is called.
InitialCounter may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.
During decryption the Progress event will fire as data is decrypted.
Decrypt Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessageB = new byte[] { 0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76 };
chacha.Decrypt();
Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
AEAD Notes
When decrypting AdditionalAuthData must be set to the same value that was specified when encrypting. AuthTag must be set to the AuthTag value produced when encrypting.
Note: IncludeAuthTag may be set to True if the AuthTag value was included in the encrypted message.
Decrypt with AEAD Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.AuthTagB = new byte[] { 0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78 };
chacha.InputMessageB = new byte[] { 0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65 };
chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.Decrypt();
Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
DecryptBlock Method (Chacha Class)
Decrypts a block and returns the decrypted data.
Syntax
public byte[] decryptBlock(byte[] inputBuffer, boolean lastBlock);
Remarks
DecryptBlock will decrypt the input data and return the decrypted block. The decrypted block will always be the same length as the encrypted data. The following properties are applicable:
InputBuffer specifies the input data to decrypt.
LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the class will validate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.
DecryptBlock Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
cahcha.AuthTagB = authTag; //Value calculated during encryption.
byte[] tempDecryptedBlock;
//Decrypt any number of blocks of any size
tempDecryptedBlock = chacha.DecryptBlock(part1, false);
tempDecryptedBlock = chacha.DecryptBlock(part2, false);
//Pass true for the last block
tempDecryptedBlock = chacha.DecryptBlock(part3, true);
Encrypt Method (Chacha Class)
Encrypts the data.
Syntax
public void encrypt();
Remarks
Encrypt will encrypt the specified data. The following properties are applicable:
- IV (required)
- Key (required)
- UseAEAD (optional)
- AdditionalAuthData (optional - applicable if UseAEAD is True);
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
Additional Notes
The Key property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If KeyPassword is set both Key and IV will be automatically generated when Encrypt is called.
The IV should typically be set to a 96 bit (12 byte) value. See the IV property for details on using a 64 bit (8 byte) value. If IV is not set a 96 bit (12 byte) value will automatically be generated by the class when Encrypt is called.
InitialCounter may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.
During encryption the Progress event will fire as data is encrypted.
Encrypt Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[]{ 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();
//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes.
// {0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76}
AEAD Notes
When encrypting and UseAEAD is True AdditionalAuthData optionally holds data that is authenticated but not encrypted.
After encrypting the message the AuthTag property will be populated. To include the AuthTag in the output set IncludeAuthTag to True.
Encrypt with AEAD Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();
//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes:
// {0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65}
//chacha.AuthTagB contains the byte[] of the AuthTag. The above code produces the following authentication tag:
// {0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78}
EncryptBlock Method (Chacha Class)
Encrypts data and returns the encrypted block.
Syntax
public byte[] encryptBlock(byte[] inputBuffer, boolean lastBlock);
Remarks
EncryptBlock will encrypt the input data and return the encrypted block. The encrypted block will always be the same length as the decrypted data. The following properties are applicable:
InputBuffer specifies the input data to encrypt.
LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the class will calculate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.
EncryptBlock Example
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
byte[] tempEncryptedBlock;
//Encrypt any number of blocks of any size
tempEncryptedBlock = chacha.EncryptBlock(part1, false);
tempEncryptedBlock = chacha.EncryptBlock(part2, false);
//Pass true for the last block
tempEncryptedBlock = chacha.EncryptBlock(part3, true);
//Save AuthTag for use when decrypting
byte[] authTab = chacha.AuthTagB;
Reset Method (Chacha Class)
Resets the class.
Syntax
public void reset();
Remarks
When called, the class will reset all of its properties to their default values.
SetInputStream Method (Chacha Class)
Sets the stream from which the class will read data to encrypt or decrypt.
Syntax
public void setInputStream(java.io.InputStream inputStream);
Remarks
This method sets the stream from which the class will read data to encrypt or decrypt.
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
- SetInputStream
- InputFile
- InputMessage
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
SetOutputStream Method (Chacha Class)
Sets the stream to which the class will write encrypted or decrypted data.
Syntax
public void setOutputStream(java.io.OutputStream outputStream);
Remarks
This method sets the stream to which the class will write encrypted or decrypted data.
Input and Output Properties
The class will determine the source and destination of the input and output based on which properties are set.
The order in which the input properties are checked is as follows:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.
When using streams you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.
Error Event (Chacha Class)
Information about errors during data delivery.
Syntax
public class DefaultChachaEventListener implements ChachaEventListener { ... public void error(ChachaErrorEvent e) {} ... } public class ChachaErrorEvent { public int errorCode; public String description; }
Remarks
The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.
ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.
Progress Event (Chacha Class)
Fired as progress is made.
Syntax
public class DefaultChachaEventListener implements ChachaEventListener { ... public void progress(ChachaProgressEvent e) {} ... } public class ChachaProgressEvent { public long bytesProcessed; public int percentProcessed; }
Remarks
This event is fired automatically as data is processed by the class.
The PercentProcessed parameter indicates the current status of the operation.
The BytesProcessed parameter holds the total number of bytes processed so far.
Config Settings (Chacha Class)
The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.ChaCha Config Settings
When Encrypt is called the class will perform the encryption as normal and then encode the output as specified here. OutputMessage or OutputFile will hold the encoded data.
When Decrypt is called the class will expect InputMessage or InputFile to hold the encoded data as specified here. The class will then decode the data and perform decryption as normal.
Possible values are:
- 0 (none - default)
- 1 (Base64)
- 2 (Hex)
- 3 (Base64URL)
Note: This setting cannot be used in conjunction with DecryptBlock. When calling DecryptBlock AuthTag must be set explicitly and the cipher text being decrypted must not include the auth tag.
Note: When decrypting, if IncludeIV is set to True and the IV length was NOT 12 bytes when originally encrypting the data, this setting must be set to the appropriate value before calling Decrypt or DecryptBlock.
- "SHA1"
- "MD2"
- "MD5" (default)
- "HMAC-SHA1"
- "HMAC-SHA224"
- "HMAC-SHA256"
- "HMAC-SHA384"
- "HMAC-SHA512"
- "HMAC-MD5"
- "HMAC-RIPEMD160"
When using any HMAC algorithm the PBKDF#2 method from RFC 2898 is used. Any other algorithm uses PBKDF#1 from the same RFC.
Base Config Settings
In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting GUIAvailable to false will ensure that the class does not attempt to process external events.
- Product: The product the license is for.
- Product Key: The key the license was generated from.
- License Source: Where the license was found (e.g., RuntimeLicense, License File).
- License Type: The type of license installed (e.g., Royalty Free, Single Server).
- Last Valid Build: The last valid build number for which the license will work.
This setting only works on these classes: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.
Setting this setting to true tells the class to use the internal implementation instead of using the system security libraries.
This setting is set to false by default on all platforms.
Trappable Errors (Chacha Class)
ChaCha Errors
| 101 Unsupported algorithm. | |
| 102 No Key specified. | |
| 103 No IV specified. | |
| 104 Cannot read or write file. | |
| 107 Block size is not valid for this algorithm. | |
| 108 Key size is not valid for this algorithm. | |
| 111 OutputFile already exists and Overwrite is False. | |
| 121 The specified key is invalid. | |
| 123 IV size is not valid for this algorithm. | |
| 304 Cannot write file. | |
| 305 Cannot read file. | |
| 306 Cannot create file. | |
| 2004 Invalid padding. This may be an indication that the key is incorrect. |