Ethereum Classic (ETC) is a cryptocurrency that operates on a decentralized platform, allowing users to build, deploy, and run smart contracts and decentralized applications. It is a continuation of the original Ethereum blockchain after the infamous hard fork in 2016.

Ethereum Classic stands out for its immutable blockchain, which means that past transactions or data recorded on the blockchain cannot be changed. This is achieved through the use of cryptographic hashes, unique identifiers for each block. Tampering with a previous block's data would alter the hash, revealing any attempt to tamper with the blockchain.

The immutability of ETC's blockchain has important implications. It guarantees the security and transparency of the historical record of transactions. Anyone can independently verify transactions recorded on the Ethereum Classic blockchain, establishing a high level of trust. This is especially vital for financial transactions and applications that require an unalterable record.

The Russian Ruble (RUB) is the official currency of Russia, issued by the Central Bank of Russia. It is widely used in trade across Eastern Europe and Asia, especially in energy markets. In the crypto space, RUB trading pairs are available on select exchanges, and Russia has explored blockchain-based financial systems as part of its digital economy initiatives.