It depends on the blockchain platform as well, but usually public blockchain platforms are pseudonym,
    meaning there is no identity information associated to the addresses.
    The transactions between different addresses are visible however,
    so with the help of transaction graph analysis there is a chance to conclude to the real identity.
    Transaction graph analysis is made usually more difficult, like with the help of creating a new address for each transaction at Bitcoin, or with built in mixing services in Dash.

    Consortium Blockchain solutions provide a different philosophy, they are usually not anonym at all, like with built in identity services at Hyperledger.

    In blockchain systems (i.e. Bitcoin and Ethereum) you must have an account to participate in the system. These are not traditional accounts like Facebook where you provide personally identifiable information such as email to create it. Blockchain accounts are created by generating a cryptographic public/private keypair (i.e. you generate 2 strings called a public key and a private key that look something like “0x7891E7682e00d5760b127887A00eE334B8C759d8”). Your public key serves as the uniquely identifiable address for your blockchain account, so if someone wants to send you money they would send it to this address. Since you participate in the blockchain using this public address, no transactions are specifically traceable to you.

    HOWEVER, this does not mean your activity is 100% anonymous but rather pseudonymous i.e. you operate under another name like “0x7891E7682e00d5760b127887A00eE334B8C759d8”. As long as this pseudonym cannot be linked to you, your personal identity remains secret. For example, let’s say the authorities seized an enterprise operating using Bitcoin. The authorities could see which Bitcoin addresses sent money to this enterprise using the public blockchain. They could then cross-reference these Bitcoin addresses with information from third parties (like a Bitcoin exchange) to try and link a personal identity to the Bitcoin address. Another way for identity leaks to occur is when interacting with an online merchant that uses browser cookies, a common web tracking tool. If the merchant is not careful, their cookies can expose personal information (such as email) and Bitcoin addresses, allowing an eavesdropper sniffing the cookies to link the identities.