**javacard.security** ====Class MessageDigest ==== *[[javacard:java-card-api:object|java.lang.Object]] \\ **Direct Known Subclasses:** [[javacard:java-card-api:InitializedMessageDigest|InitializedMessageDigest]] ---- public abstract class **MessageDigest**extends [[javacard:java-card-api:Object|Object]] The MessageDigest class is the base class for hashing algorithms. Implementations of MessageDigest algorithms must extend this class and implement all the abstract methods. A tear or card reset event resets a MessageDigest object to the initial state (state upon construction). Even if a transaction is in progress, update of intermediate result state in the implementation instance shall not participate in the transaction. ---- ^ Field Summary ^^ | **static byte** | **[[javacard:java-card-api:MessageDigest#ALG_MD5|ALG_MD5]] **          Message Digest algorithm MD5. | | **static byte** | **[[javacard:java-card-api:MessageDigest#ALG_RIPEMD160|ALG_RIPEMD160]] **          Message Digest algorithm RIPE MD-160. | | **static byte** | **[[javacard:java-card-api:MessageDigest#ALG_SHA|ALG_SHA]] **          Message Digest algorithm SHA. | | **static byte** | **[[javacard:java-card-api:MessageDigest#ALG_SHA_256|ALG_SHA_256]] **          Message Digest algorithm SHA-256. | | **static byte** | **[[javacard:java-card-api:MessageDigest#ALG_SHA_384|ALG_SHA_384]] **          Message Digest algorithm SHA-384. | | **static byte** | **[[javacard:java-card-api:MessageDigest#ALG_SHA_512|ALG_SHA_512]] **          Message Digest algorithm SHA-512. | | **static byte** | **[[javacard:java-card-api:MessageDigest#LENGTH_MD5|LENGTH_MD5]] **          Length of digest in bytes for SHA | | **static byte** | **[[javacard:java-card-api:MessageDigest#LENGTH_RIPEMD160|LENGTH_RIPEMD160]] **          Length of digest in bytes for RIPE MD-160 | | **static byte** | **[[javacard:java-card-api:MessageDigest#LENGTH_SHA|LENGTH_SHA]] **          Length of digest in bytes for SHA-256 | | **static byte** | **[[javacard:java-card-api:MessageDigest#LENGTH_SHA_256|LENGTH_SHA_256]] **          Length of digest in bytes for MD5 | | **static byte** | **[[javacard:java-card-api:MessageDigest#LENGTH_SHA_384|LENGTH_SHA_384]] **          Length of digest in bytes for SHA-384 | | **static byte** | **[[javacard:java-card-api:MessageDigest#LENGTH_SHA_512|LENGTH_SHA_512]] **          Length of digest in bytes for SHA-512 |   ^ Constructor Summary ^^ | **protected ** | **[[javacard:java-card-api:MessageDigest#MessageDigest()|MessageDigest]] **()          Protected Constructor |   ^ Method Summary ^^ | **abstract  short** | **[[javacard:java-card-api:MessageDigest#doFinal(byte[], short, short, byte[], short)|doFinal]] **(byte[] inBuff,short inOffset,short inLength,byte[] outBuff,short outOffset)          Generates a hash of all/last input data. | | **abstract  byte** | **[[javacard:java-card-api:MessageDigest#getAlgorithm()|getAlgorithm]] **()          Gets the Message digest algorithm. | | **static [[javacard:java-card-api:InitializedMessageDigest|InitializedMessageDigest]] ** | **[[javacard:java-card-api:MessageDigest#getInitializedMessageDigestInstance(byte, boolean)|getInitializedMessageDigestInstance]] **(byte algorithm,boolean externalAccess)          Creates a InitializedMessageDigest object instance of the selected algorithm. | | **static [[javacard:java-card-api:MessageDigest|MessageDigest]] ** | **[[javacard:java-card-api:MessageDigest#getInstance(byte, boolean)|getInstance]] **(byte algorithm,boolean externalAccess)          Creates a MessageDigest object instance of the selected algorithm. | | **abstract  byte** | **[[javacard:java-card-api:MessageDigest#getLength()|getLength]] **()          Returns the byte length of the hash. | | **abstract  void** | **[[javacard:java-card-api:MessageDigest#reset()|reset]] **()          Resets the MessageDigest object to the initial state for further use. | | **abstract  void** | **[[javacard:java-card-api:MessageDigest#update(byte[], short, short)|update]] **(byte[] inBuff,short inOffset,short inLength)          Accumulates a hash of the input data. |   ^ Methods inherited from class java.lang.Object ^ | [[javacard:java-card-api:Object#equals(java.lang.Object)|equals]] |   ^ Field Detail ^ === ALG_SHA === public static final byte **ALG_SHA** Message Digest algorithm SHA. The block size used by this algorithm is 64 bytes. **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.ALG_SHA|Constant Field Values]] ---- === ALG_MD5 === public static final byte **ALG_MD5** Message Digest algorithm MD5. The block size used by this algorithm is 64 bytes. **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.ALG_MD5|Constant Field Values]] ---- === ALG_RIPEMD160 === public static final byte **ALG_RIPEMD160** Message Digest algorithm RIPE MD-160. The block size used by this algorithm is 64 bytes. **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.ALG_RIPEMD160|Constant Field Values]] ---- === ALG_SHA_256 === public static final byte **ALG_SHA_256** Message Digest algorithm SHA-256. The block size used by this algorithm is 64 bytes. **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.ALG_SHA_256|Constant Field Values]] ---- === ALG_SHA_384 === public static final byte **ALG_SHA_384** Message Digest algorithm SHA-384. The block size used by this algorithm is 128 bytes. **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.ALG_SHA_384|Constant Field Values]] ---- === ALG_SHA_512 === public static final byte **ALG_SHA_512** Message Digest algorithm SHA-512. The block size used by this algorithm is 128 bytes. **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.ALG_SHA_512|Constant Field Values]] ---- === LENGTH_MD5 === public static final byte **LENGTH_MD5** Length of digest in bytes for SHA **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.LENGTH_MD5|Constant Field Values]] ---- === LENGTH_RIPEMD160 === public static final byte **LENGTH_RIPEMD160** Length of digest in bytes for RIPE MD-160 **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.LENGTH_RIPEMD160|Constant Field Values]] ---- === LENGTH_SHA === public static final byte **LENGTH_SHA** Length of digest in bytes for SHA-256 **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.LENGTH_SHA|Constant Field Values]] ---- === LENGTH_SHA_256 === public static final byte **LENGTH_SHA_256** Length of digest in bytes for MD5 **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.LENGTH_SHA_256|Constant Field Values]] ---- === LENGTH_SHA_384 === public static final byte **LENGTH_SHA_384** Length of digest in bytes for SHA-384 **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.LENGTH_SHA_384|Constant Field Values]] ---- === LENGTH_SHA_512 === public static final byte **LENGTH_SHA_512** Length of digest in bytes for SHA-512 **See Also:**[[javacard:java-card-api:constant-values#javacard.security.MessageDigest.LENGTH_SHA_512|Constant Field Values]] ^ Constructor Detail ^ === MessageDigest === protected **MessageDigest**() Protected Constructor ^ Method Detail ^ === getInstance === public static final [[javacard:java-card-api:MessageDigest|MessageDigest]] **getInstance**(byte algorithm, boolean externalAccess) throws [[javacard:java-card-api:CryptoException|CryptoException]] Creates a MessageDigest object instance of the selected algorithm. **Parameters:**algorithm - the desired message digest algorithm. Valid codes listed in ALG_* constants above, for example, [[javacard:java-card-api:MessageDigest#ALG_SHA|ALG_SHA]] . externalAccess - true indicates that the instance will be shared among multiple applet instances and that the MessageDigest instance will also be accessed (via a Shareable. interface) when the owner of the MessageDigest instance is not the currently selected applet. If true the implementation must not allocate CLEAR_ON_DESELECT transient space for internal data. **Returns:**the MessageDigest object instance of the requested algorithm **Throws:** [[javacard:java-card-api:CryptoException|CryptoException]] - with the following reason codes: \\ *CryptoException.NO_SUCH_ALGORITHM if the requested algorithm or shared access mode is not supported. \\ ---- === getInitializedMessageDigestInstance === public static final [[javacard:java-card-api:InitializedMessageDigest|InitializedMessageDigest]] **getInitializedMessageDigestInstance**(byte algorithm, boolean externalAccess) throws [[javacard:java-card-api:CryptoException|CryptoException]] Creates a InitializedMessageDigest object instance of the selected algorithm. **Parameters:**algorithm - the desired message digest algorithm. Valid codes listed in ALG_* constants above, for example, [[javacard:java-card-api:MessageDigest#ALG_SHA|ALG_SHA]] . externalAccess - true indicates that the instance will be shared among multiple applet instances and that the InitializedMessageDigest instance will also be accessed (via a Shareable. interface) when the owner of the InitializedMessageDigest instance is not the currently selected applet. If true the implementation must not allocate CLEAR_ON_DESELECT transient space for internal data. **Returns:**the InitializedMessageDigest object instance of the requested algorithm **Throws:** [[javacard:java-card-api:CryptoException|CryptoException]] - with the following reason codes: \\ *CryptoException.NO_SUCH_ALGORITHM if the requested algorithm or shared access mode is not supported. \\ **Since:** 2.2.2 ---- === getAlgorithm === public abstract byte **getAlgorithm**() Gets the Message digest algorithm. **Returns:**the algorithm code defined above ---- === getLength === public abstract byte **getLength**() Returns the byte length of the hash. **Returns:**hash length ---- === doFinal === public abstract short **doFinal**(byte[] inBuff, short inOffset, short inLength, byte[] outBuff, short outOffset) throws [[javacard:java-card-api:CryptoException|CryptoException]] Generates a hash of all/last input data. Completes and returns the hash computation after performing final operations such as padding. The MessageDigest object is reset to the initial state after this call is made. The input and output buffer data may overlap. **Parameters:**inBuff - the input buffer of data to be hashed inOffset - the offset into the input buffer at which to begin hash generation inLength - the byte length to hash outBuff - the output buffer, may be the same as the input buffer outOffset - the offset into the output buffer where the resulting hash value begins **Returns:**number of bytes of hash output in outBuff **Throws:** [[javacard:java-card-api:CryptoException|CryptoException]] - with the following reason codes: \\ *CryptoException.ILLEGAL_USE if the accumulated message length is greater than the maximum length supported by the algorithm. \\ ---- === update === public abstract void **update**(byte[] inBuff, short inOffset, short inLength) throws [[javacard:java-card-api:CryptoException|CryptoException]] Accumulates a hash of the input data. This method requires temporary storage of intermediate results. In addition, if the input data length is not block aligned (multiple of block size) then additional internal storage may be allocated at this time to store a partial input data block. This may result in additional resource consumption and/or slow performance. This method should only be used if all the input data required for the hash is not available in one byte array. If all of the input data required for the hash is located in a single byte array, use of the doFinal() method is recommended. The doFinal() method must be called to complete processing of input data accumulated by one or more calls to the update() method. Note: \\ *//If //inLength// is 0 this method does nothing.// \\ **Parameters:**inBuff - the input buffer of data to be hashed inOffset - the offset into the input buffer at which to begin hash generation inLength - the byte length to hash **Throws:** [[javacard:java-card-api:CryptoException|CryptoException]] - with the following reason codes: \\ *CryptoException.ILLEGAL_USE if the accumulated message length is greater than the maximum length supported by the algorithm. \\ **See Also:**[[javacard:java-card-api:MessageDigest#doFinal(byte[], short, short, byte[], short)|doFinal]] ---- === reset === public abstract void **reset**() Resets the MessageDigest object to the initial state for further use.