+@subsubsection BCAL-Basic context
+Besides the context types for individual ciphers there is a generic context
+type for BCAL. This is the context to use when using BCAL based functions.
+The BCAL context has the following structure:
+@verbatim
+typedef struct{
+ bcdesc_t* desc_ptr;
+ uint16_t keysize;
+ void* ctx;
+} bcgen_ctx_t;
+@end verbatim
+@table @code
+@item desc_ptr
+a pointer to the BCAL descriptor
+@item keysize
+the chosen keysize
+@item ctx
+pointer to the cipher specific context
+@end table
+
+
+
+@subsubsection BCAL-Basic
+BCAL-Basic provides the basic features of an block cipher on top of the
+BCAL. To use it you simply have to include the algorithms you want to use,
+the BCAL descriptor file and of course the BCAL-Basic implementation.
+
+The following functions are provided:
+@table @code
+@item bcal_cipher_init
+@code{uint8_t bcal_cipher_init(const bcdesc_t* cipher_descriptor, const void* key, uint16_t keysize_b, bcgen_ctx_t* ctx)}
+ this function initializes a BCAL context based on the given BCAL descriptor
+ pointer (first parameter) with a given key (second parameter) of a given length
+ (third parameter). The context to initialize is designated by the pointer
+ passed as fourth parameter.
+
+ If everything works fine @samp{0} is returned. In the case something fails
+ the following codes are returned:
+@table @samp
+ @item 1
+ The specified keysize is not available with this cipher
+ @item 2
+ It was not possible to allocate enough memory to hold the key.
+ (This is returned when there is no actual init function and you ran out
+ of memory)
+ @item 3
+ It was not possible to allocate enough memory to hold the context variable
+ for the selected cipher.
+@end table
+
+@item bcal_cipher_free
+@code{void bcal_cipher_free(bcgen_ctx_t* ctx)} this function frees the memory
+allocated by the init function and should be called whenever you are finished
+with BCAL context. It automatically also calls the @code{free} function if
+necessary.
+
+@item bcal_cipher_enc
+@code{void bcal_cipher_enc(void* block, const bcgen_ctx_t* ctx)}
+this function encrypts a block in-place using a given BCAL contex.