# Migrate to Cryptonote v8

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Author: Andrew Chiw


Status: proposal/rejected









QRL Improvement Proposal (QIP-001)

## Overview & status

Author: Andrew Chiw
Status: proposal/rejected
Created: 2018-10-30
Discussions: https://github.com/theQRL/qips/pull/2

[View more QRL Improvement Proposals](/roadmap/#qips).





Abstract This QIP explores the feasibility of migrating to Cryptonote v8, and continuing to change the POW algorithm just like Monero.
Motivation ASIC resistance is the most obvious reason, so that GPU miners can participate, thus making mining truly decentralized, instead of the select few who can afford to buy and setup ASICs.
Implementation at library level Currently, qryptonight implements Cryptonote v7 via hooking into a few important files in xmr-stak, and putting a SWIG wrapper around it.
Since xmr-stak 2.5.0 (931bd5fef17f908afc62836ae7b6ea087d1441ca, unify cpu cryptonight implementations), the internals have changed enough that qryptonight needs to be modified, and xmr-stak needs to be forked.
Once this is done, having qryptonight use Cryptonote v8 is as simple as changing this line:
1 Cryptonight_hash<1>::template hash<cryptonight_monero, false, false>(input.data(), input.size(), output.data(), &context); to this:
1 Cryptonight_hash<1>::template hash<cryptonight_monero_v8, false, false>(input.data(), input.size(), output.data(), &context); Implementation at node level This breaks the following tests:
1 2 3 4 5 6 7 8 TestChainManagerReal.test_add_block TestChainManagerReal.test_multi_output_transaction_add_block TestChainManagerReal.test_simple_add_block TestBlockHeader.test_hash TestBlockHeader.test_hash_nonce TestQryptonight.test_hash TestQryptonight.test_hash2 TestQryptonight.test_hash3 From these tests it appears that the code does not depend too much on the POW algorithm, which is good news.
Backwards compatibility Both algorithms will need to be present in qryptonight, and qryptonight must be modified to accept an extra argument that specifies which hashing algorithm should be used.
The best place for the node to decide which hashing algorithm should be used is BlockHeader, specifically generate_headerhash() and validate().
The exact block height from which Cryptonote v8 should be used instead of v7 should be defined in config.dev.
Considerations This work will have to be duplicated in go-qrl.
Should Monero’s future POW algorithms require a different amount of memory than Cryptonight v7/v8, further modifications need to be made to qryptonight and xmr-stak in cryptonote_alloc_ctx().