SymmetricCrypto Class

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The SymmetricCrypto class provides capabilities of encrypting and decrypting binary data.

Syntax

secureblackbox.SymmetricCrypto

Remarks

SymmetricCrypto allows you to encrypt and decrypt uninterpreted binary data with a symmetric block encryption cipher.

SymmetricCrypto is one of the low-level cryptography classes (alongside PublicKeyCrypto and HashFunction) offered by SecureBlackbox. It allows to encrypt pools of binary data with a chosen symmetric encryption cipher. It can be used as a standalone encryption mechanism (for example, for encrypting database data or setting files), or as part of a larger security system (such as PKCS#7 or PGP).

Encryption and decryption with SymmetricCrypto broadly consists of three steps: configuring the encryption parameters, setting up the key material, and actually encrypting or decrypting the data.

Configuring encryption parameters

When preparing SymmetricCrypto for action, you need to fine-tune several cryptographic encryption parameters. Normally these would be given to you by the party that expects you to encrypt or decrypt their data (for example: 'AES128-CBC, with the IV of all zeroes').

As a rule, the following parameters need to be selected/adjusted:

• EncryptionAlgorithm, such as AES128, 3DES, or Blowfish.
• Encryption Mode, such as CBC, CTR, GCM or CCM.
• Block Padding for data lengths that are not multiples of the cipher's block size (none, PKCS5, or ANXI X9.23).
• TagSize (for AEAD algorithms only).
• HashAlgorithm and MACAlgorithm (for algorithms that require them).

Setting up the key material

Symmetric algorithms use short (typically, 16-32 bytes) encryption keys. The exact key length depends on the encryption algorithm used (for example, 16 bytes for AES128). You can use the KeySize property to learn the expected key length for the chosen EncryptionAlgorithm.

In addition to keys, many encryption modes require additional data. These are typically represented by an Initialization Vector (IV) and a Nonce. The IV is a randomized public part of the encryption key, which is used to avoid re-use of the same encryption key for different data. Nonce is similar in meaning to the initialization vector, but applies to the algorithm and not the key.

Any key material that you assign to SymmetricCrypto should be first loaded into the CryptoKeyManager object. Once you have done that, simply assign the key object returned by the CryptoKeyManager to the Key property. Note that while the IV needs to be provided to the CryptoKeyManager, the Nonce needs to be assigned directly to Nonce property of the SymmetricCrypto object.

Note that CryptoKeyManager lets you to form the encryption key in a few ways: by loading it from memory or file, generating a new random key, or deriving it from a password. Use the method that is the most appropriate in your circumstances.

Encrypting and decrypting data

Now that the component has been set up, you can proceed to the actual encryption or decryption operation. There are a few options you can use here:

• Encrypt (or decrypt) a buffer to a buffer using Encrypt (Decrypt).
• Encrypt a file to a file using EncryptFile.
• Encrypt a stream to a stream using EncryptStream.
• Encrypt longer data chunk by chunk using a sequence of EncryptInit, EncryptUpdate, EncryptUpdate, ..., EncryptUpdate, EncryptFinal calls.

If you are using an authenticated encryption algorithm that can take additional associated data (AEAD), you can provide that via the AssociatedData property.

Please find an example of using SymmetricCrypto to encrypt and decrypt a file below: //encrypting a file SymmetricCrypto symmetricCrypto = new SymmetricCrypto(); symmetricCrypto.setEncryptionAlgorithm("RC4"); // default AES256 // generating a key from a password CryptoKeyManager keyManager = new CryptoKeyManager(); keyManager.deriveKey(256, "MyPassword",""); keyManager.getKey().setIV(new byte[16]); symmetricCrypto.setKey(keyManager.getKey()); // the encoding to apply to the output data, default cetDefault which depends on // the operation and type of key being used symmetricCrypto.setOutputEncoding(SymmetricCrypto.cetBinary); // first parameter is the path of the file you want to encrypt and the second is the path // of where the encrypted file will be saved symmetricCrypto.encryptFile("./message.txt","encryptedFile.bin"); // decrypting a file symmetricCrypto.reset(); symmetricCrypto.setKey(keyManager.getKey()); // first parameter is the path of the file you want to decrypt and the second is the path // of where the decrypted file will be saved symmetricCrypto.decryptFile("encryptedFile.bin","decryptedFile.bin");

Property List

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The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

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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

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The following is a list of config settings for the class with short descriptions. Click on the links for further details.

AssociatedData Property (SymmetricCrypto Class)

Provides Associated Data for AEAD algorithms.

Syntax

public byte[] getAssociatedData();
public void setAssociatedData(byte[] associatedData);

Remarks

Use this property to set up Associated Data for AEAD encryption algorithms.

This property is not available at design time.

BlockSize Property (SymmetricCrypto Class)

The block size of the chosen symmetric cipher.

Syntax

public int getBlockSize();

Default Value

0

Remarks

This property returns the block size of the chosen symmetric cipher.

Modern symmetric algorithms typically use blocks of 16 bytes. Some older algorithms, such as DES or Blowfish, use 8-byte blocks.

This property is read-only.

EncryptionAlgorithm Property (SymmetricCrypto Class)

The encryption algorithm to use for encrypting the data.

Syntax

public String getEncryptionAlgorithm();
public void setEncryptionAlgorithm(String encryptionAlgorithm);

Default Value

"AES256"

Remarks

This property specifies the base symmetric algorithm to use (e.g. AES128). Use it in conjunction with Mode to set up the complete encryption scheme (such as AES128-CBC or AES128-GCM).

FIPSMode Property (SymmetricCrypto Class)

Reserved.

Syntax

public boolean isFIPSMode();
public void setFIPSMode(boolean FIPSMode);

Default Value

False

Remarks

This property is reserved for future use.

HashAlgorithm Property (SymmetricCrypto Class)

The hash algorithm to use during encryption.

Syntax

public String getHashAlgorithm();
public void setHashAlgorithm(String hashAlgorithm);

Default Value

"SHA256"

Remarks

Use this property to provide the hash algorithm to be used with the encryption operation. This only applies to certain encryption algorithms/modes.

InputEncoding Property (SymmetricCrypto Class)

The encoding to apply to the input data.

Syntax

public int getInputEncoding();
public void setInputEncoding(int inputEncoding);

Enumerated values:
  public final static int cetDefault = 0;
  public final static int cetBinary = 1;
  public final static int cetBase64 = 2;
  public final static int cetCompact = 3;
  public final static int cetJSON = 4;

Default Value

0

Remarks

Key Property (SymmetricCrypto Class)

The key to use for the cryptographic operation.

Syntax

public CryptoKey getKey();
public void setKey(CryptoKey key);

Remarks

Use this property to provide the symmetric key to use for the cryptographic operation. Remember that this key should be of appropriate type and length, and any required additional settings (such as IV or Nonce) should be adjusted where appropriate.

This property is not available at design time.

Please refer to the CryptoKey type for a complete list of fields.

KeySize Property (SymmetricCrypto Class)

Returns the cryptographic key size in bytes.

Syntax

public int getKeySize();

Default Value

0

Remarks

Use this property to read the cryptographic key size. For the majority of the symmetric algorithms this is hard-coded in the algorithm itself (such as 16 bytes for AES128), but may be variable for certain exceptions, such as Blowfish or RC4.

This property is read-only.

MACAlgorithm Property (SymmetricCrypto Class)

The (H)MAC algorithm to use during encryption.

Syntax

public String getMACAlgorithm();
public void setMACAlgorithm(String MACAlgorithm);

Default Value

""

Remarks

Use this property to configure the HMAC algorithm to use with the encryption operation. This only applies to a small subset of algorithms/modes.

Mode Property (SymmetricCrypto Class)

Specifies the symmetric cipher mode of operation.

Syntax

public int getMode();
public void setMode(int mode);

Enumerated values:
  public final static int scmDefault = 0;
  public final static int scmECB = 1;
  public final static int scmCBC = 2;
  public final static int scmCTR = 3;
  public final static int scmCFB8 = 4;
  public final static int scmGCM = 5;
  public final static int scmCCM = 6;
  public final static int scmPoly1305 = 7;
  public final static int scmOCB = 8;

Default Value

0

Remarks

Use this property to specify the mode of operation as required by your environment. The default setting is CBC.

Nonce Property (SymmetricCrypto Class)

Specifies the Nonce value to employ.

Syntax

public byte[] getNonce();
public void setNonce(byte[] nonce);

Remarks

Use this property to specify the Nonce value for the symmetric operation. Not every algorithm or mode uses nonce.

This property is not available at design time.

OutputEncoding Property (SymmetricCrypto Class)

The encoding to apply to the output data.

Syntax

public int getOutputEncoding();
public void setOutputEncoding(int outputEncoding);

Enumerated values:
  public final static int cetDefault = 0;
  public final static int cetBinary = 1;
  public final static int cetBase64 = 2;
  public final static int cetCompact = 3;
  public final static int cetJSON = 4;

Default Value

0

Remarks

Padding Property (SymmetricCrypto Class)

The padding type to apply to the encrypted data.

Syntax

public int getPadding();
public void setPadding(int padding);

Enumerated values:
  public final static int scpNone = 0;
  public final static int scpPKCS5 = 1;
  public final static int scpANSIX923 = 2;

Default Value

1

Remarks

Use this property to specify the padding type to use with the encrypted data. A padding type commonly used in modern security environments is PKCS#5.

PayloadSize Property (SymmetricCrypto Class)

Specifies the payload size, in bytes.

Syntax

public int getPayloadSize();
public void setPayloadSize(int payloadSize);

Default Value

0

Remarks

Use this property to specify the size of the input data in bytes. This is only used by a subset of algorithms/modes, such as CCM.

StreamCipher Property (SymmetricCrypto Class)

Returns true if the selected algorithms works as a stream cipher.

Syntax

public boolean isStreamCipher();

Default Value

False

Remarks

This property returns true if the selected algorithm processes data as a stream (byte-by-byte), rather than block-by-block. This affects the need to use a proper padding settings.

This property is read-only and not available at design time.

TagSize Property (SymmetricCrypto Class)

Specifies the AEAD tag size, in bytes.

Syntax

public int getTagSize();
public void setTagSize(int tagSize);

Default Value

16

Remarks

Use this property to specify/customize the tag size for AEAD encryption.

Config Method (SymmetricCrypto 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 (SymmetricCrypto Class)

Decrypts a buffer.

Syntax

public byte[] decrypt(byte[] buffer);

Remarks

Use this method to decrypt a byte array and get the encrypted message in another byte array.

Specify the decryption key in Key property.

DecryptFile Method (SymmetricCrypto Class)

Decrypts a file.

Syntax

public void decryptFile(String sourceFile, String destFile);

Remarks

Use this method to decrypt an encrypted file and save the decrypted data to another file.

Specify the decryption key in Key property before calling this method.

DecryptFinal Method (SymmetricCrypto Class)

Finalization of decryption by blocks.

Syntax

public byte[] decryptFinal();

Remarks

Use this method to finalize of decryption by blocks.

Specify decryption key in Key property.

DecryptInit Method (SymmetricCrypto Class)

Initializes a per-block decryption process.

Syntax

public void decryptInit();

Remarks

Use this method to start a block-by-block decryption process.

Specify the decryption key in Key property before starting the decryption.

DecryptStream Method (SymmetricCrypto Class)

Decrypts a stream.

Syntax

public void decryptStream(java.io.InputStream sourceStream, java.io.OutputStream destStream);

Remarks

Use this method to decrypt a stream and save the decrypted message to another stream.

Specify the decryption key in Key property before commencing the decryption.

DecryptUpdate Method (SymmetricCrypto Class)

Decrypts the next block of encrypted data.

Syntax

public byte[] decryptUpdate(byte[] buffer);

Remarks

When using block-by-block decryption, pass every subsequent block of the encrypted message to this method until the entire message is processed. For each encrypted block the method returns a piece of decrypted data.

Please note that in general case there is no direct correspondence between the data actually contained in the encrypted block with the output of this method. The component may choose to cache a piece of the provided buffer internally if it doesn't constitute a full block of encrypted data.

Remember to call DecryptInit before calling this method to prepare the control for the decryption process.

DoAction Method (SymmetricCrypto Class)

Performs an additional action.

Syntax

public String doAction(String actionID, String actionParams);

Remarks

DoAction is a generic method available in every class. It is used to perform an additional action introduced after the product major release. The list of actions is not fixed, and may be flexibly extended over time.

The unique identifier (case insensitive) of the action is provided in the ActionID parameter.

ActionParams contains the value of a single parameter, or a list of multiple parameters for the action in the form of PARAM1=VALUE1;PARAM2=VALUE2;....

Common ActionIDs:

Encrypt Method (SymmetricCrypto Class)

Encrypts a buffer.

Syntax

public byte[] encrypt(byte[] buffer);

Remarks

Use this method to encrypt a byte array and get the protected message in another byte array.

Specify the encryption key in Key property before calling this method.

This is a one-off encryption method. Don't use it with granular per-block methods (EncryptInit, EncryptUpdate, EncryptFinal).

EncryptFile Method (SymmetricCrypto Class)

Encrypts a file.

Syntax

public void encryptFile(String sourceFile, String destFile);

Remarks

Use this method to encrypt a file and save the protected message in another file.

Specify the encryption key in Key property before commencing encryption.

EncryptFinal Method (SymmetricCrypto Class)

Finalization of encryption by blocks.

Syntax

public byte[] encryptFinal();

Remarks

Use this method to finalize of encryption by blocks.

Specify encryption key in Key property.

EncryptInit Method (SymmetricCrypto Class)

Initializes a per-block encryption process.

Syntax

public void encryptInit();

Remarks

Use this method to initialize a block-by-block encryption process. Follow it with calls to EncryptUpdate (as many as needed), and complete the encryption with an EncryptFinal call.

Specify the encryption key in Key property before calling this method.

EncryptStream Method (SymmetricCrypto Class)

Encrypts a stream.

Syntax

public void encryptStream(java.io.InputStream sourceStream, java.io.OutputStream destStream);

Remarks

Use this method to encrypt a stream and save the protected message into another stream.

Specify the encryption key in the Key property before calling this method.

This is a one-off encryption method. Don't use it together with granular per-block encryption methods such as EncryptInit, EncryptUpdate, and EncryptFinal.

EncryptUpdate Method (SymmetricCrypto Class)

Encrypts the next block of data.

Syntax

public byte[] encryptUpdate(byte[] buffer);

Remarks

Use this method to encrypt the next block of data contained in Buffer.

Call this method after calling EncryptInit for as many times as needed, until the whole volume of data is processed. Having done that, call EncryptFinal to complete the encryption and get the terminating encrypted trailer.

Reset Method (SymmetricCrypto Class)

Resets the class settings.

Syntax

public void reset();

Remarks

Reset is a generic method available in every class.

Error Event (SymmetricCrypto Class)

Reports errors during encryption or decryption.

Syntax

public class DefaultSymmetricCryptoEventListener implements SymmetricCryptoEventListener {
  ...
  public void error(SymmetricCryptoErrorEvent e) {}
  ...
}

public class SymmetricCryptoErrorEvent {
  public int errorCode;
  public String description;
}

Remarks

class fires this event in case of exceptional conditions during a cryptographic operation.

ErrorCode contains an error code and Description contains a textual description of the error.

Notification Event (SymmetricCrypto Class)

This event notifies the application about an underlying control flow event.

Syntax

public class DefaultSymmetricCryptoEventListener implements SymmetricCryptoEventListener {
  ...
  public void notification(SymmetricCryptoNotificationEvent e) {}
  ...
}

public class SymmetricCryptoNotificationEvent {
  public String eventID;
  public String eventParam;
}

Remarks

The class fires this event to let the application know about some event, occurrence, or milestone in the class. For example, it may fire to report completion of the document processing. The list of events being reported is not fixed, and may be flexibly extended over time.

The unique identifier of the event is provided in the EventID parameter. EventParam contains any parameters accompanying the occurrence. Depending on the type of the class, the exact action it is performing, or the document being processed, one or both may be omitted.

Progress Event (SymmetricCrypto Class)

Reports the data encryption/decryption progress.

Syntax

public class DefaultSymmetricCryptoEventListener implements SymmetricCryptoEventListener {
  ...
  public void progress(SymmetricCryptoProgressEvent e) {}
  ...
}

public class SymmetricCryptoProgressEvent {
  public long total;
  public long current;
  public boolean cancel; //read-write
}

Remarks

This event fires periodically during a file encrypt/decrypt operation to report its progress.

Use the Cancel parameter to terminate the encryption/decryption if needed.

CryptoKey Type

This container represents a cryptographic key.

Remarks

This type is a universal placeholder for cryptographic keys.

Fields

Constructors

public CryptoKey();

Config Settings (SymmetricCrypto 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.

SymmetricCrypto Config Settings

Base Config Settings

Trappable Errors (SymmetricCrypto Class)

SymmetricCrypto Errors