tls1_prf_P_hash
if (!tls1_prf_P_hash(mdctx, sec, L_S1,
if (!tls1_prf_P_hash(sha1ctx, sec + slen - L_S2, L_S2,
if (!tls1_prf_P_hash(mdctx, sec, slen, seed, seed_len, out, olen))