Dagger-Hashimoto is a research implementation and specification for the Ethereum 1.0 mining algorithm and the predecessor of Ethash.
Dagger Hashimoto aspires to achieve two objectives at the same time:
1- ASIC-resistance: design the algorithm so that specialized hardware like ASIC miners aren't much more profitable to mine with than non-specialist hardware like CPUs and GPUs, reducing the centralized nature of Ethereum mining.
2- Verifiability by a light client: a block should be relatively easy to verify by a light client.
Dagger Hashimoto was created on the foundation of two works: Hashimoto and Dagger. Thaddeus Dryja invented the Hashimoto method to make memory reads the limiting element in the mining process. Hashimoto based his argument on the notion that RAM is a more versatile component than compute, making RAM better for assessing algorithms. Vitalik Buterin devised the Dagger algorithm. It employs directed acyclic graphs to simultaneously perform memory-intensive calculations and memory-light validations. It's supposed to be a replacement for algorithms like Scrypt, however it's been shown to be vulnerable to shared memory hardware acceleration.