Class Base64


  • public class Base64
    extends BaseNCodec
    Provides Base64 encoding and decoding as defined by RFC 2045.

    This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein.

    The class can be parameterized in the following manner with various constructors:

    • URL-safe mode: Default off.
    • Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    • Line separator: Default is CRLF ("\r\n")

    The URL-safe parameter is only applied to encode operations. Decoding seamlessly handles both modes.

    Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).

    This class is thread-safe.

    Since:
    1.0
    See Also:
    RFC 2045
    • Constructor Summary

      Constructors 
      Constructor Description
      Base64()
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
      Base64​(boolean urlSafe)
      Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
      Base64​(int lineLength)
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
      Base64​(int lineLength, byte[] lineSeparator)
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
      Base64​(int lineLength, byte[] lineSeparator, boolean urlSafe)
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    • Constructor Detail

      • Base64

        public Base64()
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.

        When decoding all variants are supported.

      • Base64

        public Base64​(boolean urlSafe)
        Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.

        When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.

        When decoding all variants are supported.

        Parameters:
        urlSafe - if true, URL-safe encoding is used. In most cases this should be set to false.
        Since:
        1.4
      • Base64

        public Base64​(int lineLength)
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.

        Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

        When decoding all variants are supported.

        Parameters:
        lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
        Since:
        1.4
      • Base64

        public Base64​(int lineLength,
                      byte[] lineSeparator)
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

        Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

        When decoding all variants are supported.

        Parameters:
        lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
        lineSeparator - Each line of encoded data will end with this sequence of bytes.
        Throws:
        IllegalArgumentException - Thrown when the provided lineSeparator included some base64 characters.
        Since:
        1.4
      • Base64

        public Base64​(int lineLength,
                      byte[] lineSeparator,
                      boolean urlSafe)
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

        Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

        When decoding all variants are supported.

        Parameters:
        lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
        lineSeparator - Each line of encoded data will end with this sequence of bytes.
        urlSafe - Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode operations. Decoding seamlessly handles both modes. Note: no padding is added when using the URL-safe alphabet.
        Throws:
        IllegalArgumentException - Thrown when the lineSeparator contains Base64 characters.
        Since:
        1.4
    • Method Detail

      • decodeBase64

        public static byte[] decodeBase64​(byte[] base64Data)
        Decodes Base64 data into octets.

        Note: this method seamlessly handles data encoded in URL-safe or normal mode.

        Parameters:
        base64Data - Byte array containing Base64 data
        Returns:
        Array containing decoded data.
      • decodeBase64

        public static byte[] decodeBase64​(byte[] base64Data,
                                          int off,
                                          int len)
      • decodeBase64

        public static byte[] decodeBase64​(String base64String)
        Decodes a Base64 String into octets.

        Note: this method seamlessly handles data encoded in URL-safe or normal mode.

        Parameters:
        base64String - String containing Base64 data
        Returns:
        Array containing decoded data.
        Since:
        1.4
      • decodeBase64URLSafe

        public static byte[] decodeBase64URLSafe​(String base64String)
      • decodeInteger

        public static BigInteger decodeInteger​(byte[] pArray)
        Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature.
        Parameters:
        pArray - a byte array containing base64 character data
        Returns:
        A BigInteger
        Since:
        1.4
      • encodeBase64

        public static byte[] encodeBase64​(byte[] binaryData)
        Encodes binary data using the base64 algorithm but does not chunk the output.
        Parameters:
        binaryData - binary data to encode
        Returns:
        byte[] containing Base64 characters in their UTF-8 representation.
      • encodeBase64

        public static byte[] encodeBase64​(byte[] binaryData,
                                          boolean isChunked)
        Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
        Parameters:
        binaryData - Array containing binary data to encode.
        isChunked - if true this encoder will chunk the base64 output into 76 character blocks
        Returns:
        Base64-encoded data.
        Throws:
        IllegalArgumentException - Thrown when the input array needs an output array bigger than Integer.MAX_VALUE
      • encodeBase64

        public static byte[] encodeBase64​(byte[] binaryData,
                                          boolean isChunked,
                                          boolean urlSafe)
        Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
        Parameters:
        binaryData - Array containing binary data to encode.
        isChunked - if true this encoder will chunk the base64 output into 76 character blocks
        urlSafe - if true this encoder will emit - and _ instead of the usual + and / characters. Note: no padding is added when encoding using the URL-safe alphabet.
        Returns:
        Base64-encoded data.
        Throws:
        IllegalArgumentException - Thrown when the input array needs an output array bigger than Integer.MAX_VALUE
        Since:
        1.4
      • encodeBase64

        public static byte[] encodeBase64​(byte[] binaryData,
                                          boolean isChunked,
                                          boolean urlSafe,
                                          int maxResultSize)
        Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
        Parameters:
        binaryData - Array containing binary data to encode.
        isChunked - if true this encoder will chunk the base64 output into 76 character blocks
        urlSafe - if true this encoder will emit - and _ instead of the usual + and / characters. Note: no padding is added when encoding using the URL-safe alphabet.
        maxResultSize - The maximum result size to accept.
        Returns:
        Base64-encoded data.
        Throws:
        IllegalArgumentException - Thrown when the input array needs an output array bigger than maxResultSize
        Since:
        1.4
      • encodeBase64Chunked

        public static byte[] encodeBase64Chunked​(byte[] binaryData)
        Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
        Parameters:
        binaryData - binary data to encode
        Returns:
        Base64 characters chunked in 76 character blocks
      • encodeBase64String

        public static String encodeBase64String​(byte[] binaryData)
        Encodes binary data using the base64 algorithm but does not chunk the output. NOTE: We changed the behavior of this method from multi-line chunking (commons-codec-1.4) to single-line non-chunking (commons-codec-1.5).
        Parameters:
        binaryData - binary data to encode
        Returns:
        String containing Base64 characters.
        Since:
        1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not).
      • encodeBase64URLSafe

        public static byte[] encodeBase64URLSafe​(byte[] binaryData)
        Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of + and / characters. Note: no padding is added.
        Parameters:
        binaryData - binary data to encode
        Returns:
        byte[] containing Base64 characters in their UTF-8 representation.
        Since:
        1.4
      • encodeBase64URLSafeString

        public static String encodeBase64URLSafeString​(byte[] binaryData)
        Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of + and / characters. Note: no padding is added.
        Parameters:
        binaryData - binary data to encode
        Returns:
        String containing Base64 characters
        Since:
        1.4
      • encodeInteger

        public static byte[] encodeInteger​(BigInteger bigInteger)
        Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature.
        Parameters:
        bigInteger - a BigInteger
        Returns:
        A byte array containing base64 character data
        Throws:
        NullPointerException - if null is passed in
        Since:
        1.4
      • isBase64

        public static boolean isBase64​(byte octet)
        Returns whether or not the octet is in the base 64 alphabet.
        Parameters:
        octet - The value to test
        Returns:
        true if the value is defined in the the base 64 alphabet, false otherwise.
        Since:
        1.4
      • isBase64

        public static boolean isBase64​(byte[] arrayOctet)
        Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.
        Parameters:
        arrayOctet - byte array to test
        Returns:
        true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise
        Since:
        1.5
      • isBase64

        public static boolean isBase64​(String base64)
        Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.
        Parameters:
        base64 - String to test
        Returns:
        true if all characters in the String are valid characters in the Base64 alphabet or if the String is empty; false, otherwise
        Since:
        1.5
      • isInAlphabet

        protected boolean isInAlphabet​(byte octet)
        Returns whether or not the octet is in the Base64 alphabet.
        Specified by:
        isInAlphabet in class BaseNCodec
        Parameters:
        octet - The value to test
        Returns:
        true if the value is defined in the the Base64 alphabet false otherwise.
      • isUrlSafe

        public boolean isUrlSafe()
        Returns our current encode mode. True if we're URL-SAFE, false otherwise.
        Returns:
        true if we're in URL-SAFE mode, false otherwise.
        Since:
        1.4