> For the complete documentation index, see [llms.txt](https://satoshichain.gitbook.io/satoshi-chain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://satoshichain.gitbook.io/satoshi-chain/developers/4.2-satoshichain-cross-chain-protocol.md).

# 4.2 SatoshiChain Cross-Chain Protocol

This SatoshiChain Cross-Chain Protocol is essential to linking the original Bitcoin blockchain to the SatoshiChain. This protocol uses a fixed ratio of `1:100,000,000 BTC:SAT` to enter or exit the SatoshiChain. When users peg their Bitcoin to the SatoshiChain, the SatoshiChain protocol mints Satoshi tokens ($SAT). \
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Conversely, when a user destroys $SAT tokens, he can withdraw bitcoin from the SatoshiChain chain using a ratio of 100,000,000:1. In this context, a cross-chain bridge protocol module will be utilized to achieve cross-chain transactions. . \
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The primary features of the cross-chain protocol are:

1. Decentralized and secure cross-chain support of Bitcoin to SatoshiChain
2. A trustless key generation for threshold signature schemes. Generated private shares of the signing key will be used to calculate final signed transactions. 
3. The private key shares will also be managed by the community and third-party partners to eliminate any risk of a single-point-of-failure (i.e., centralization). 
4. The protocol governance mechanism supports voting capabilities for organizations that run on the cross-chain protocol.

<figure><img src="/files/wNC8qTfQtox5VrX97wNr" alt=""><figcaption><p><strong>Fig 3.</strong> SatoshiChain Cross-Chain Protocol</p></figcaption></figure>