Package com.blockchyp.client.crypto

Class CryptoUtils

java.lang.Object

com.blockchyp.client.crypto.CryptoUtils

public final class CryptoUtils
extends Object

This is utility class providing cryptography support for the BlockChyp client. It handles the authorization headers required for direct gateway requests along with AES encryption for the offline route cache.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	AES_KEY_SIZE_IN_BYTES
static final String	AUTH_SCHEME_DUAL
static final String	HEADER_AUTHORIZATION
static final String	HEADER_NONCE
static final String	HEADER_TIMESTAMP
static final int	NONCE_SIZE_IN_BYTES

Method Summary

Modifier and Type	Method	Description
String	computeSHA256(String hex)	Computes a SHA 256 hash of the given hex.
String	decrypt(String cipherText, byte[] key)	Decrypts ciphertext previously encoded with encrypt(java.lang.String,byte[]).
String	encrypt(String plainText, byte[] key)	Encrypts the given plain text using the given key using AES with PKCS#5 padding.
Map<String,String>	generateApiHeaders(String apiKey, String bearerToken, String signingKey)	Generates the big three API request headers based on the input credentials.
String	generateTimestamp()	Generates a timestamp encoded for use in Gateway API request headers.
static CryptoUtils	getInstance()	Returns the CryptoUtils singleton.
byte[]	randomBytes(int len)	Returns an array of random bytes of the given length.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

HEADER_NONCE

public static final String HEADER_NONCE

See Also:

• Constant Field Values

HEADER_TIMESTAMP

public static final String HEADER_TIMESTAMP

See Also:

• Constant Field Values

HEADER_AUTHORIZATION

public static final String HEADER_AUTHORIZATION

See Also:

• Constant Field Values

AUTH_SCHEME_DUAL

public static final String AUTH_SCHEME_DUAL

See Also:

• Constant Field Values

AES_KEY_SIZE_IN_BYTES

public static final int AES_KEY_SIZE_IN_BYTES

See Also:

• Constant Field Values

NONCE_SIZE_IN_BYTES

public static final int NONCE_SIZE_IN_BYTES

See Also:

• Constant Field Values

Method Details

getInstance

public static CryptoUtils getInstance()

Returns the CryptoUtils singleton.

Returns:

an instance of CryptoUtils

computeSHA256

public String computeSHA256(String hex)

Computes a SHA 256 hash of the given hex.

Parameters:

hex - data to be hashed in hex format.

Returns:

hex encoded hash of the input data

generateApiHeaders

public Map<String,String> generateApiHeaders(String apiKey,
 String bearerToken,
 String signingKey)

Generates the big three API request headers based on the input credentials.

Parameters:

apiKey - BlockChyp API Key (root or transient)

bearerToken - BlockChyp Bearer Token (root or transient)

signingKey - BlockChyp Signing Key (root or transient)

Returns:

a Map containing the API request headers.

generateTimestamp

public String generateTimestamp()

Generates a timestamp encoded for use in Gateway API request headers.

Returns:

ISO encoded UTC timestamp string.

decrypt

public String decrypt(String cipherText,
 byte[] key)
               throws Exception

Decrypts ciphertext previously encoded with encrypt(java.lang.String,byte[]).

Parameters:

cipherText - the initialization vector and ciphertext separated by a pipe character.

key - the AES encryption to use.

Returns:

the plain text

Throws:

Exception - if the decryption or associated encoding operations fail.

encrypt

public String encrypt(String plainText,
 byte[] key)
               throws Exception

Encrypts the given plain text using the given key using AES with PKCS#5 padding. Generates and returns a CBC initialization vector prepended to the main ciphertext.

Parameters:

plainText - the message to be encrypted

key - AES encryption key

Returns:

return hex encoded initialization vector and ciphertext, pipe delimited.

Throws:

Exception - if an error occurs during encryption or encoding.

randomBytes

public byte[] randomBytes(int len)

Returns an array of random bytes of the given length.

Parameters:

len - Number of random bytes to return.

Returns:

byte[]