# Package javax.crypto

package javax.crypto
Provides the classes and interfaces for cryptographic operations. The cryptographic operations defined in this package include encryption, key generation and key agreement, and Message Authentication Code (MAC) generation.

Support for encryption includes symmetric, asymmetric, block, and stream ciphers. This package also supports secure streams and sealed objects.

Many of the classes provided in this package are provider-based. The class itself defines a programming interface to which applications may write. The implementations themselves may then be written by independent third-party vendors and plugged in seamlessly as needed. Therefore, application developers may take advantage of any number of provider-based implementations without having to add or rewrite code.

- Java Security Standard Algorithm Names Specification

## Related Documentation

For further documentation, please see:

- Java Cryptography Architecture (JCA) Reference Guide
- How to Implement a Provider in the Java Cryptography Architecture

Since:
  1.4
External Specifications
  - Java Security Standard Algorithm Names

Related Packages
Package
Description
javax.crypto.interfaces
Provides interfaces for Diffie-Hellman keys as defined in RSA Laboratories' PKCS #3.
javax.crypto.spec
Provides classes and interfaces for key specifications and algorithm parameter specifications.
Class
Description
AEADBadTagException
This exception is thrown when a `Cipher` operating in an AEAD mode (such as GCM/CCM) is unable to verify the supplied authentication tag.
BadPaddingException
This exception is thrown when a particular padding mechanism is expected for the input data but the data is not padded properly.
Cipher
This class provides the functionality of a cryptographic cipher for encryption and decryption.
CipherInputStream
A `CipherInputStream` is composed of an `InputStream` and a `Cipher` object so that read() methods return data that are read in from the underlying `InputStream` but have been additionally processed by the `Cipher` object.
CipherOutputStream
A `CipherOutputStream` is composed of an `OutputStream` and a `Cipher` object so that write() methods first process the data before writing them out to the underlying `OutputStream`.
CipherSpi
This class defines the Service Provider Interface (SPI) for the `Cipher` class.
DecapsulateException
An exception that is thrown by the `KEM.Decapsulator.decapsulate(byte[])` method to denote an error during decapsulation.
EncryptedPrivateKeyInfo
This class implements the `EncryptedPrivateKeyInfo` type as defined in PKCS #8.
ExemptionMechanism
This class provides the functionality of an exemption mechanism, examples of which are key recovery, key weakening, and key escrow.
ExemptionMechanismException
This is the generic ExemptionMechanism exception.
ExemptionMechanismSpi
This class defines the Service Provider Interface (SPI) for the `ExemptionMechanism` class.
IllegalBlockSizeException
This exception is thrown when the length of data provided to a block cipher is incorrect, i.e., does not match the block size of the cipher.
KDF
This class provides the functionality of a Key Derivation Function (KDF), which is a cryptographic algorithm for deriving additional keys from input keying material (IKM) and (optionally) other data.
KDFParameters
A specification of Key Derivation Function (`KDF`) parameters.
KDFSpi
This class defines the Service Provider Interface (SPI) for the Key Derivation Function (`KDF`) class.
KEM
This class provides the functionality of a Key Encapsulation Mechanism (KEM).
KEM.Decapsulator
A decapsulator, generated by `KEM.newDecapsulator(PrivateKey)` on the KEM receiver side.
KEM.Encapsulated
This class specifies the return value of the encapsulate method of a Key Encapsulation Mechanism (KEM), which includes the shared secret (as a `SecretKey`), the key encapsulation message, and optional parameters.
KEM.Encapsulator
An encapsulator, generated by `KEM.newEncapsulator(PublicKey)` on the KEM sender side.
KEMSpi
This class defines the Service Provider Interface (SPI) for the `KEM` class.
KEMSpi.DecapsulatorSpi
The KEM decapsulator implementation, generated by `KEMSpi.engineNewDecapsulator(PrivateKey, AlgorithmParameterSpec)` on the KEM receiver side.
KEMSpi.EncapsulatorSpi
The KEM encapsulator implementation, generated by `KEMSpi.engineNewEncapsulator(PublicKey, AlgorithmParameterSpec, SecureRandom)` on the KEM sender side.
KeyAgreement
This class provides the functionality of a key agreement (or key exchange) protocol.
KeyAgreementSpi
This class defines the Service Provider Interface (SPI) for the `KeyAgreement` class.
KeyGenerator
This class provides the functionality of a secret (symmetric) key generator.
KeyGeneratorSpi
This class defines the Service Provider Interface (SPI) for the `KeyGenerator` class.
Mac
This class provides the functionality of a "Message Authentication Code" (MAC) algorithm.
MacSpi
This class defines the Service Provider Interface (SPI) for the `Mac` class.
NoSuchPaddingException
This exception is thrown when a particular padding mechanism is requested but is not available in the environment.
NullCipher
The `NullCipher` class is a class that provides an "identity cipher" -- one that does not transform the plain text.
SealedObject
This class enables a programmer to create an object and protect its confidentiality with a cryptographic algorithm.
SecretKey
A secret (symmetric) key.
SecretKeyFactory
This class represents a factory for secret keys.
SecretKeyFactorySpi
This class defines the Service Provider Interface (SPI) for the `SecretKeyFactory` class.
ShortBufferException
This exception is thrown when an output buffer provided by the user is too short to hold the operation result.