Returns an autoreleased data instance initialised with pseudo-random bytes of the specified length.
On failure returns nil. This may be due to:
A zero length or unreasonably large length argument or,
Failure to allocate memory to hold the random data or,
Failure of the underlying random data generation.

Returns an NSString object containing a backslash escaped representation of the receiver.

Returns a buffer containing an ASCII backslash escaped representation of the receiver, (and optionally the size of the buffer excluding the trailing nul terminator).

Returns data formed by gunzipping the contents of the receiver.
If the receiver did not contain data produced by gzip, this method simply returns the receiver.
If the gnuzipping failed, this method returns nil.
Otherwise, the returned object is an autorelease mutable data object.

Returns data formed by gzipping the contents of the receiver using the specified compression level (from 0 to 9 with 0 meaning no compression and 9 meaning maximum compression). Use a value outside the 0 to 9 range (eg -1) to employ the default compression.
NB. It is permissable to gzip an empty data object, and it is also permissable to gzip a data object which already contains gzipped data.
Returns nil on failure.

Returns an NSString object containing an ASCII hexadecimal representation of the receiver. This means that the returned object will contain exactly twice as many characters as there are bytes as the receiver, as each byte in the receiver is represented by two hexadecimal digits.
The high order four bits of each byte is encoded before the low order four bits. Capital letters 'A' to 'F' are used to represent values from 10 to 15.

Returns a buffer containing an ASCII string with a nul terminated hexadecimal representation of the receiver, (and optionally the size of the buffer excluding the trailing nul terminator).

Initialises the receiver with the supplied string data which contains a hexadecimal coding of the bytes. The parsing of the string is fairly tolerant, ignoring whitespace and permitting both upper and lower case hexadecimal digits (the -hexadecimalRepresentation method produces a string using only uppercase digits with no white space).
If the string does not contain one or more pairs of hexadecimal digits then an exception is raised.

Returns YES if the receiver is a non-empty data object with a gzip header, NO otherwise.

Creates an MD5 digest of the information stored in the receiver and returns it as an autoreleased 16 byte NSData object.
If you need to produce a digest of string information, you need to decide what character encoding is to be used and convert your string to a data object of that encoding type first using the [NSString -dataUsingEncoding:] method -

   myDigest = [[myString dataUsingEncoding: NSUTF8StringEncoding] md5Digest];
 

If you need to use the digest in a human readable form, you will probably want it to be seen as 32 hexadecimal digits, and can do that using the -hexadecimalRepresentation method.

Decodes the source data from uuencoded and return the result.
Returns the encoded file name in namePtr if it is not null. Returns the encoded file mode in modePtr if it is not null.

Encode the source data to uuencoded.
Uses the supplied name as the filename in the encoded data, and says that the file mode is as specified.
If no name is supplied, uses untitled as the name.