What is a PDA?

In the Solana blockchain, a PDA is a Program Derived Address, a special type of address that is generated by a program in Solana rather than directly by a user's private key. This is a special type of address that is generated by Solana's program, rather than being directly derived from a user's private key.

The main purpose of a PDA is to allow a program to own and control certain data or assets without the need for a traditional private key signature. Read this and still confused, it's okay, let's take this concept apart and explain it in more detail. Solana, like Ethereum, has three things: private keys, public keys, and mnemonics.

The private key is kept private, and when we authorize a transaction, we need to sign and "authorize" the transaction with the private key. The private key is a garbled string of code, not easy to remember, with a corresponding mnemonic string. The mnemonic can be derived from the private key by an algorithm, so in practice all we need to do is memorize the mnemonic when using the wallet. And we can deduce the public key from the private key by using a cryptographic algorithm. The public key can be shown to others, who transfer money to you through your public key, and also the public key is the address of the program, which is also called program_id.

It's important to note that we can only derive the private key from the mnemonic word through the encryption algorithm, and the public key from the private key, and we can't reverse the process of deriving the private key from the public key, and the mnemonic word from the private key. Otherwise all the tokens in our encrypted addresses could be controlled by anyone.

The process of this is calculated through the ECDSA algorithm, so if you wish to understand the exact principles you can start by understanding the ECDSA algorithm. But understanding PDA accounts can be done without going so deep.