Package org.owasp.esapi.reference.crypto

Class JavaEncryptor

  • All Implemented Interfaces:
    Encryptor
    public final class JavaEncryptor
extends java.lang.Object
implements Encryptor
    Reference implementation of the Encryptor interface. This implementation layers on the JCE provided cryptographic package. Algorithms used are configurable in the ESAPI.properties file. The main property controlling the selection of this class is ESAPI.Encryptor. Most of the other encryption related properties have property names that start with the string "Encryptor.".
    Since:
    June 1, 2007; some methods since ESAPI Java 2.0
    Author:
    Jeff Williams (jeff.williams .at. aspectsecurity.com) Aspect Security, kevin.w.wall@gmail.com, Chris Schmidt (chrisisbeef .at. gmail.com)
    See Also:
    Encryptor

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      PlainText decrypt​(javax.crypto.SecretKey key, CipherText ciphertext)
      Decrypts the provided CipherText using the information from it and the specified secret key.
      PlainText decrypt​(CipherText ciphertext)
      Decrypts the provided CipherText using the information from it and the master encryption key as specified by the property Encryptor.MasterKey as defined in the ESAPI.properties file.
      CipherText encrypt​(javax.crypto.SecretKey key, PlainText plain)
      Encrypts the provided plaintext bytes using the cipher transformation specified by the property Encryptor.CipherTransformation as defined in the ESAPI.properties file and the specified secret key.
      CipherText encrypt​(PlainText plaintext)
      Encrypts the provided plaintext bytes using the cipher transformation specified by the property Encryptor.CipherTransformation and the master encryption key as specified by the property Encryptor.MasterKey as defined in the ESAPI.properties file.
      static Encryptor getInstance()  
      long getRelativeTimeStamp​(long offset)
      Gets an absolute timestamp representing an offset from the current time to be used by other functions in the library.
      long getTimeStamp()
      Gets a timestamp representing the current date and time to be used by other functions in the library.
      java.lang.String hash​(java.lang.String plaintext, java.lang.String salt)
      Returns a string representation of the hash of the provided plaintext and salt.
      java.lang.String hash​(java.lang.String plaintext, java.lang.String salt, int iterations)
      Returns a string representation of the hash of the provided plaintext and salt.
      static void main​(java.lang.String[] args)
      Generates a new strongly random secret key and salt that can be copy and pasted in the ESAPI.properties file.
      java.lang.String seal​(java.lang.String data, long expiration)
      Creates a seal that binds a set of data and includes an expiration timestamp.
      java.lang.String sign​(java.lang.String data)
      Create a digital signature for the provided data and return it in a string.
      java.lang.String unseal​(java.lang.String seal)
      Unseals data (created with the seal method) and throws an exception describing any of the various problems that could exist with a seal, such as an invalid seal format, expired timestamp, or decryption error.
      boolean verifySeal​(java.lang.String seal)
      Verifies a seal (created with the seal method) and throws an exception describing any of the various problems that could exist with a seal, such as an invalid seal format, expired timestamp, or data mismatch.
      boolean verifySignature​(java.lang.String signature, java.lang.String data)
      Verifies a digital signature (created with the sign method) and returns the boolean result.

      • Methods inherited from class java.lang.Object

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

    • Method Detail

      • main

        public static void main​(java.lang.String[] args)
                 throws java.lang.Exception
        Generates a new strongly random secret key and salt that can be copy and pasted in the ESAPI.properties file.
        Parameters:
        args - Set first argument to "-print" to display available algorithms on standard output.
        Throws:
        java.lang.Exception - To cover a multitude of sins, mostly in configuring ESAPI.properties.

      • hash

        public java.lang.String hash​(java.lang.String plaintext,
                             java.lang.String salt)
                      throws EncryptionException
        Returns a string representation of the hash of the provided plaintext and salt. The salt helps to protect against a rainbow table attack by mixing in some extra data with the plaintext. Some good choices for a salt might be an account name or some other string that is known to the application but not to an attacker. See this article for more information about hashing as it pertains to password schemes. Hashes the data with the supplied salt and the number of iterations specified in the ESAPI SecurityConfiguration.
        Specified by:
        hash in interface Encryptor
        Parameters:
        plaintext - the plaintext String to encrypt
        salt - the salt to add to the plaintext String before hashing
        Returns:
        the encrypted hash of 'plaintext' stored as a String
        Throws:
        EncryptionException - if the specified hash algorithm could not be found or another problem exists with the hashing of 'plaintext'

      • hash

        public java.lang.String hash​(java.lang.String plaintext,
                             java.lang.String salt,
                             int iterations)
                      throws EncryptionException
        Returns a string representation of the hash of the provided plaintext and salt. The salt helps to protect against a rainbow table attack by mixing in some extra data with the plaintext. Some good choices for a salt might be an account name or some other string that is known to the application but not to an attacker. See this article for more information about hashing as it pertains to password schemes. Hashes the data using the specified algorithm and the Java MessageDigest class. This method first adds the salt, a separator (":"), and the data, and then rehashes the specified number of iterations in order to help strengthen weak passwords.
        Specified by:
        hash in interface Encryptor
        Parameters:
        plaintext - the plaintext String to encrypt
        salt - the salt to add to the plaintext String before hashing
        iterations - the number of times to iterate the hash
        Returns:
        the encrypted hash of 'plaintext' stored as a String
        Throws:
        EncryptionException - if the specified hash algorithm could not be found or another problem exists with the hashing of 'plaintext'

      • encrypt

        public CipherText encrypt​(PlainText plaintext)
                   throws EncryptionException
        Encrypts the provided plaintext bytes using the cipher transformation specified by the property Encryptor.CipherTransformation and the master encryption key as specified by the property Encryptor.MasterKey as defined in the ESAPI.properties file.

        Specified by:
        encrypt in interface Encryptor
        Parameters:
        plaintext - The PlainText to be encrypted.
        Returns:
        the CipherText object from which the raw ciphertext, the IV, the cipher transformation, and many other aspects about the encryption detail may be extracted.
        Throws:
        EncryptionException - Thrown if something should go wrong such as the JCE provider cannot be found, the cipher algorithm, cipher mode, or padding scheme not being supported, specifying an unsupported key size, specifying an IV of incorrect length, etc.
        See Also:
        Encryptor.encrypt(SecretKey, PlainText)

      • encrypt

        public CipherText encrypt​(javax.crypto.SecretKey key,
                          PlainText plain)
                   throws EncryptionException
        Encrypts the provided plaintext bytes using the cipher transformation specified by the property Encryptor.CipherTransformation as defined in the ESAPI.properties file and the specified secret key.

        This method is similar to Encryptor.encrypt(PlainText) except that it permits a specific SecretKey to be used for encryption.

        Specified by:
        encrypt in interface Encryptor
        Parameters:
        key - The SecretKey to use for encrypting the plaintext.
        plain - The byte stream to be encrypted. Note if a Java String is to be encrypted, it should be converted using "some string".getBytes("UTF-8").
        Returns:
        the CipherText object from which the raw ciphertext, the IV, the cipher transformation, and many other aspects about the encryption detail may be extracted.
        Throws:
        EncryptionException - Thrown if something should go wrong such as the JCE provider cannot be found, the cipher algorithm, cipher mode, or padding scheme not being supported, specifying an unsupported key size, specifying an IV of incorrect length, etc.
        See Also:
        Encryptor.encrypt(PlainText)

      • decrypt

        public PlainText decrypt​(CipherText ciphertext)
                  throws EncryptionException
        Decrypts the provided CipherText using the information from it and the master encryption key as specified by the property Encryptor.MasterKey as defined in the ESAPI.properties file.

        Specified by:
        decrypt in interface Encryptor
        Parameters:
        ciphertext - The CipherText object to be decrypted.
        Returns:
        The PlainText object resulting from decrypting the specified ciphertext. Note that it it is desired to convert the returned plaintext byte array to a Java String is should be done using new String(byte[], "UTF-8"); rather than simply using new String(byte[]); which uses native encoding and may not be portable across hardware and/or OS platforms.
        Throws:
        EncryptionException - Thrown if something should go wrong such as the JCE provider cannot be found, the cipher algorithm, cipher mode, or padding scheme not being supported, specifying an unsupported key size, or incorrect encryption key was specified or a PaddingException occurs.
        See Also:
        Encryptor.decrypt(SecretKey, CipherText)

      • decrypt

        public PlainText decrypt​(javax.crypto.SecretKey key,
                         CipherText ciphertext)
                  throws EncryptionException,
                         java.lang.IllegalArgumentException
        Decrypts the provided CipherText using the information from it and the specified secret key.

        This decrypt method is similar to Encryptor.decrypt(CipherText) except that it allows decrypting with a secret key other than the master secret key.

        Specified by:
        decrypt in interface Encryptor
        Parameters:
        key - The SecretKey to use for encrypting the plaintext.
        ciphertext - The CipherText object to be decrypted.
        Returns:
        The PlainText object resulting from decrypting the specified ciphertext. Note that it it is desired to convert the returned plaintext byte array to a Java String is should be done using new String(byte[], "UTF-8"); rather than simply using new String(byte[]); which uses native encoding and may not be portable across hardware and/or OS platforms.
        Throws:
        EncryptionException - Thrown if something should go wrong such as the JCE provider cannot be found, the cipher algorithm, cipher mode, or padding scheme not being supported, specifying an unsupported key size, or incorrect encryption key was specified or a PaddingException occurs.
        java.lang.IllegalArgumentException
        See Also:
        Encryptor.decrypt(CipherText)

      • sign

        public java.lang.String sign​(java.lang.String data)
                      throws EncryptionException
        Create a digital signature for the provided data and return it in a string.

        Limitations: A new public/private key pair used for ESAPI 2.0 digital signatures with this method and Encryptor.verifySignature(String, String) are dynamically created when the default reference implementation class, JavaEncryptor is first created. Because this key pair is not persisted nor is the public key shared, this method and the corresponding Encryptor.verifySignature(String, String) can not be used with expected results across JVM instances. This limitation will be addressed in ESAPI 2.1.

        Specified by:
        sign in interface Encryptor
        Parameters:
        data - the data to sign
        Returns:
        the digital signature stored as a String
        Throws:
        EncryptionException - if the specified signature algorithm cannot be found

      • verifySignature

        public boolean verifySignature​(java.lang.String signature,
                               java.lang.String data)
        Verifies a digital signature (created with the sign method) and returns the boolean result.

        Limitations: A new public/private key pair used for ESAPI 2.0 digital signatures with this method and Encryptor.sign(String) are dynamically created when the default reference implementation class, JavaEncryptor is first created. Because this key pair is not persisted nor is the public key shared, this method and the corresponding Encryptor.sign(String) can not be used with expected results across JVM instances. This limitation will be addressed in ESAPI 2.1.

        Specified by:
        verifySignature in interface Encryptor
        Parameters:
        signature - the signature to verify against 'data'
        data - the data to verify against 'signature'
        Returns:
        true, if the signature is verified, false otherwise

      • seal

        public java.lang.String seal​(java.lang.String data,
                             long expiration)
                      throws IntegrityException
        Creates a seal that binds a set of data and includes an expiration timestamp.
        Specified by:
        seal in interface Encryptor
        Parameters:
        expiration -
        data - the data to seal
        Returns:
        the seal
        Throws:
        IntegrityException

      • unseal

        public java.lang.String unseal​(java.lang.String seal)
                        throws EncryptionException
        Unseals data (created with the seal method) and throws an exception describing any of the various problems that could exist with a seal, such as an invalid seal format, expired timestamp, or decryption error.
        Specified by:
        unseal in interface Encryptor
        Parameters:
        seal - the sealed data
        Returns:
        the original (unsealed) data
        Throws:
        EncryptionException - if the unsealed data cannot be retrieved for any reason

      • verifySeal

        public boolean verifySeal​(java.lang.String seal)
        Verifies a seal (created with the seal method) and throws an exception describing any of the various problems that could exist with a seal, such as an invalid seal format, expired timestamp, or data mismatch.
        Specified by:
        verifySeal in interface Encryptor
        Parameters:
        seal - the seal to verify
        Returns:
        true, if the seal is valid. False otherwise

      • getTimeStamp

        public long getTimeStamp()
        Gets a timestamp representing the current date and time to be used by other functions in the library.
        Specified by:
        getTimeStamp in interface Encryptor
        Returns:
        a timestamp representing the current time

      • getRelativeTimeStamp

        public long getRelativeTimeStamp​(long offset)
        Gets an absolute timestamp representing an offset from the current time to be used by other functions in the library.
        Specified by:
        getRelativeTimeStamp in interface Encryptor
        Parameters:
        offset - the offset to add to the current time
        Returns:
        the absolute timestamp