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Title: Bitcoin 4-bit computer? Post by: c6da9ef157ee76a9e913 on January 10, 2018, 06:31:49 PM Reading through the Opcodes [https://en.bitcoin.it/wiki/Script#Opcodes] the blockchain can be be used as a 4-bit computer.
Has anyone built any small 4-bit programs and tried them on a blockchain? Title: Re: Bitcoin 4-bit computer? Post by: colatkinson on January 10, 2018, 11:20:10 PM Reading through the Opcodes [https://en.bitcoin.it/wiki/Script#Opcodes] the blockchain can be be used as a 4-bit computer. Has anyone built any small 4-bit programs and tried them on a blockchain? What do you mean by this? Bitcoin script is intentionally not Turing-complete i.e. cannot be a "computer" in the typical sense. Could you give an example of a design? Title: Re: Bitcoin 4-bit computer? Post by: Colorblind on January 11, 2018, 11:06:12 AM Reading through the Opcodes [https://en.bitcoin.it/wiki/Script#Opcodes] the blockchain can be be used as a 4-bit computer. Has anyone built any small 4-bit programs and tried them on a blockchain? No it can't. You can use bitcoin script to write simple logic (for example time locked or hash locked contracts) but you can't do loops and length of your code is limited. Ethereum have much more advanced smart contract capabilities (see ethereum smart contracts, solidity programming). Title: Re: Bitcoin 4-bit computer? Post by: Andre_Goldman on January 13, 2018, 04:47:42 AM ::) This post let me thinking about ...
A trapdoor one-way function is a special type of one-way function, one with a secret trapdoor. It is easy to compute in one direction and hard to compute in the other direction. But, if you know the secret, you can easily compute the function in the other direction. That is, it is easy to compute f(x) given x, and hard to compute x given f(x). However, there is some secret information, y, such that given f(x) and y it is easy to compute x. Taking a watch apart is a good example of a trap-door one-way function. It is easy to disassemble a watch into hundreds of minuscule pieces. It is very difficult to put those tiny pieces back together into a working watch. However, with the secret information—the assembly instructions of the watch—it is much easier to put the watch back together. ISBN: 978-1-119-09672-6 Page,30 As far as I concern, SHA-2, does not have trapdoor ... BUT .... Title: Re: Bitcoin 4-bit computer? Post by: Spendulus on January 13, 2018, 05:17:38 PM Reading through the Opcodes [https://en.bitcoin.it/wiki/Script#Opcodes] the blockchain can be be used as a 4-bit computer. Has anyone built any small 4-bit programs and tried them on a blockchain? It's curious I have not even heard the phrase "4 bit computer" in decades. |