dw.crypto
Class Mac
Object
dw.crypto.Mac
This class provides the functionality of a "Message Authentication Code" (MAC) algorithm. A MAC provides a way to check the integrity of information transmitted over or stored in an unreliable medium, based on a secret key. Typically, message authentication codes are used between two parties that share a secret key in order to validate information transmitted between these parties. A MAC mechanism that is based on cryptographic hash functions is referred to as HMAC. HMAC can be used with any cryptographic hash function, e.g., MD5 or SHA-1, in combination with a secret shared key. HMAC is specified in RFC 2104.

Note: this class handles sensitive security-related data. Pay special attention to PCI DSS v3. requirements 2, 4, and 12.

Constants
HMAC_MD5  :  String = "HmacMD5"
Constant representing the HMAC-MD5 keyed-hashing algorithm as defined in RFC 2104 "HMAC: Keyed-Hashing for Message Authentication" (February 1997). This algorithm uses as MD5 cryptographic hash function
HMAC_SHA_1  :  String = "HmacSHA1"
Constant representing the HmacSHA1 algorithms as defined in RFC 2104 "HMAC: Keyed-Hashing for Message Authentication" (February 1997) with SHA-1 as the message digest algorithm.
HMAC_SHA_256  :  String = "HmacSHA256"
Constant representing the HmacSHA256 algorithms as defined in RFC 2104 "HMAC: Keyed-Hashing for Message Authentication" (February 1997) with SHA-256 as the message digest algorithm.
HMAC_SHA_384  :  String = "HmacSHA384"
Constant representing the HmacSHA384 algorithms as defined in RFC 2104 "HMAC: Keyed-Hashing for Message Authentication" (February 1997) with SHA-384 as the message digest algorithm.
HMAC_SHA_512  :  String = "HmacSHA512"
Constant representing the HmacSHA512 algorithms as defined in RFC 2104 "HMAC: Keyed-Hashing for Message Authentication" (February 1997) with SHA-512 as the message digest algorithm.
Constructor Summary
Mac(algorithm : String)
Construct a Mac encryption instance with the specified algorithm name.
Method Summary
digest(input : String, key : String) : Bytes
Computes the hash value for the passed string input using the passed secret key.
digest(input : String, key : Bytes) : Bytes
Computes the hash value for the passed string input using the passed secret key.
digest(input : Bytes, key : Bytes) : Bytes
Computes the hash value for the passed bytes input using the passed secret key.
Methods inherited from class Object
Constructor Detail
Mac
public Mac(algorithm : String)
Construct a Mac encryption instance with the specified algorithm name. The supported algorithms are:
  • MD5
  • SHA 1
  • SHA 256
  • SHA 384
  • SHA 512
Parameters:
algorithm - the standard name of the digest algorithm, must not be null.
Throws:
NullArgumentException - if algorithm is null.
IllegalArgumentException - if the specified algorithm name is not supported.

Method Detail
digest
digest(input : String, key : String) : Bytes
Computes the hash value for the passed string input using the passed secret key. Given input and the given key will be first converted with UTF-8 encoding into a byte array. The resulting hash is typically converted with base64 back into a string.
Parameters:
input - A string to calculate a RFC 2104 compliant HMAC hash value for.
key - The secret key ready for use with the algorithm. The key's format depends on the chosen algorithm and the keys are assumed to be correctly formulated for the algorithm used, for example that the lengths are correct. Keys are not checked for validity. Only such keys that have no key parameters associated with them.
Returns:
The resulting hash value as bytes.
Throws:
IllegalArgumentException - if algorithm is not null and the specified algorithm name is not supported.

digest
digest(input : String, key : Bytes) : Bytes
Computes the hash value for the passed string input using the passed secret key. Given input will be first converted with UTF-8 encoding into a byte array. The resulting hash is typically converted with base64 back into a string.
Parameters:
input - A string to calculate a RFC 2104 compliant HMAC hash value for.
key - The secret key as bytes ready for use with the algorithm. The key's format depends on the chosen algorithm and the keys are assumed to be correctly formulated for the algorithm used, for example that the lengths are correct. Keys are not checked for validity. Only such keys that have no key parameters associated with them.
Returns:
The resulting hash value as bytes.
Throws:
IllegalArgumentException - if algorithm is not null and the specified algorithm name is not supported.

digest
digest(input : Bytes, key : Bytes) : Bytes
Computes the hash value for the passed bytes input using the passed secret key.
Parameters:
input - The bytes to calculate a RFC 2104 compliant HMAC hash value.
key - The secret key as byte array ready for use with the algorithm. The key's format depends on the chosen algorithm and the keys are assumed to be correctly formulated for the algorithm used, for example that the lengths are correct. Keys are not checked for validity. Only such keys that have no key parameters associated with them.
Returns:
The resulting hash value as bytes.
Throws:
IllegalArgumentException - if algorithm is not null and the specified algorithm name is not supported.