Ravencoin code works on the PoW consensus algorithm and the x16r cryptographic algorithm, which is a combination of 16 hash functions, the order of which constantly changes depending on the hash of the previous block (its last 8 bytes are taken into account).
Ravencoin is using following hash algorithms:

• blake;
  bmw;
  groestl;
  jh;
  Keccak;
  Skein;
  Luffa;
  Cubehash;
  Shavite;
  Simd;
  Echo;
  Hamsi;
  Fugue;
  Shabal;
  Whirlpool;
  sha512.

The set of hash functions are currently identical to the X15 algorithm with the addition of SHA512. In the future the algorithms can be modified and extended to protect against ASICs.