Class DSAImplementation

Parameters:

• use_fast_math (bool) - Specify which mathematic library to use:

  • None (default). Use fastest math available.
  • True . Use fast math.
  • False . Use slow math.

• default_randfunc (callable) - Specify how to collect random data:

  • None (default). Use Random.new().read().
  • not None . Use the specified function directly.

Raises:

• RuntimeError - When use_fast_math =True but fast math is not available.

Overrides: object.__init__

Parameters:

• bits (int) - Key length, or size (in bits) of the DSA modulus p. It must be a multiple of 64, in the closed interval [512,1024].
• randfunc (callable) - Random number generation function; it should accept a single integer N and return a string of random data N bytes long. If not specified, a new one will be instantiated from Crypto.Random.
• progress_func (callable) - Optional function that will be called with a short string containing the key parameter currently being generated; it's useful for interactive applications where a user is waiting for a key to be generated.

Returns:

A DSA key object (_DSAobj).

Raises:

• ValueError - When bits is too little, too big, or not a multiple of 64.

Construct a DSA key from a tuple of valid DSA components.

The modulus p must be a prime.

The following equations must apply:

• p-1 = 0 mod q
• g^x = y mod p
• 0 < x < q
• 1 < g < p

Parameters:

• tup (tuple) - A tuple of long integers, with 4 or 5 items in the following order:

  1. Public key (y).
  2. Sub-group generator (g).
  3. Modulus, finite field order (p).
  4. Sub-group order (q).
  5. Private key (x). Optional.

Returns:

A DSA key object (_DSAobj).