1 files changed, 51 insertions, 0 deletions
diff --git a/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber512_ref/symmetric-shake.c b/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber512_ref/symmetric-shake.c
new file mode 100644
index 000000000..2317c0627
--- /dev/null
+++ b/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber512_ref/symmetric-shake.c
@@ -0,0 +1,51 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include "params.h"
+#include "symmetric.h"
+#include "fips202.h"
+
+/*************************************************
+* Name:        kyber_shake128_absorb
+*
+* Description: Absorb step of the SHAKE128 specialized for the Kyber context.
+*
+* Arguments:   - keccak_state *state: pointer to (uninitialized) output Keccak state
+*              - const uint8_t *seed: pointer to KYBER_SYMBYTES input to be absorbed into state
+*              - uint8_t i: additional byte of input
+*              - uint8_t j: additional byte of input
+**************************************************/
+void kyber_shake128_absorb(shake128incctx *state,
+                           const uint8_t seed[KYBER_SYMBYTES],
+                           uint8_t x,
+                           uint8_t y)
+{
+  uint8_t extseed[KYBER_SYMBYTES+2];
+
+  memcpy(extseed, seed, KYBER_SYMBYTES);
+  extseed[KYBER_SYMBYTES+0] = x;
+  extseed[KYBER_SYMBYTES+1] = y;
+
+  shake128_absorb_once(state, extseed, sizeof(extseed));
+}
+
+/*************************************************
+* Name:        kyber_shake256_prf
+*
+* Description: Usage of SHAKE256 as a PRF, concatenates secret and public input
+*              and then generates outlen bytes of SHAKE256 output
+*
+* Arguments:   - uint8_t *out: pointer to output
+*              - size_t outlen: number of requested output bytes
+*              - const uint8_t *key: pointer to the key (of length KYBER_SYMBYTES)
+*              - uint8_t nonce: single-byte nonce (public PRF input)
+**************************************************/
+void kyber_shake256_prf(uint8_t *out, size_t outlen, const uint8_t key[KYBER_SYMBYTES], uint8_t nonce)
+{
+  uint8_t extkey[KYBER_SYMBYTES+1];
+
+  memcpy(extkey, key, KYBER_SYMBYTES);
+  extkey[KYBER_SYMBYTES] = nonce;
+
+  shake256(out, outlen, extkey, sizeof(extkey));
+}