CAST_ofb64_encrypt
CAST_ofb64_encrypt(in, out, (long)chunk, &((EVP_CAST_KEY *)ctx->cipher_data)->ks, ctx->iv, &ctx->num);
CAST_ofb64_encrypt(in, out, (long)inl, &((EVP_CAST_KEY *)ctx->cipher_data)->ks, ctx->iv, &ctx->num);
void CAST_ofb64_encrypt(const unsigned char *in, unsigned char *out,