# Soft Covenants at CRC Garden How a CRC\-20 soft covenant holds LEAF tokens on Bitcoin, using a waiting time, an owner's signature and a Simplicity program fingerprint as its only exit\. By Crc20 Topic: Society & Business [Open the interactive Jig](https://ask.jig.com/j/DO4HVQYkE1jY) ## Transcript ### 1. A garden that keeps tokens The website crc\.garden runs CRC\-20, a way to keep tokens on Bitcoin\. Its first token is called LEAF\. A soft covenant is a special Bitcoin address that holds LEAF, like this walled garden holds its seedlings\. It has exactly one gate out\. Drag anywhere to turn the garden and look around\. ### 2. One gate, three parts Every way to spend from a Bitcoin address is a small rule called a script\. A soft covenant has only one, its single “script leaf”\. That leaf bundles three things: a program fingerprint, a waiting time and the owner’s key\. ### 3. The sealed fingerprint tag The tag is a CMR: a 32\-byte fingerprint of a program written in Simplicity, a small language for Bitcoin contracts\. The fingerprint is built into the address, but Bitcoin never runs the program\. It runs nowhere on chain, and that is why the covenant is called “soft”\. The CRC\-20 indexer, the software that keeps the LEAF ledger, reads the fingerprint only when the contract is deployed and minted\. ### 4. The waiting time The dial is the delay: from 1 to 65,535 blocks\. Bitcoin adds a block about every 10 minutes, so that is 10 minutes to about 455 days\. Each pot is one coin of the address, and a coin can only go out once it is at least that many blocks old\. The wait locks coins, not tokens: LEAF that just arrived can leave by spending an older coin of the same address\. ### 5. The owner’s lock The padlock needs a Schnorr signature: a proof made with the owner’s secret key that matches the 32\-byte public key built into the gate\. Without this lock, anyone could walk out as soon as the wait was over\. ### 6. No back door A Bitcoin Taproot address usually has a second, quicker door: one key that can spend directly\. Here that key is a “nothing up my sleeve” point that nobody holds a secret for\. The back door is bricked shut, so the gate is the only way out\. ### 7. Walking out the gate To send LEAF out, the owner spends an old enough coin and signs\. Bitcoin checks only two things: the coin’s age and the signature\. Then the CRC\-20 indexer writes the LEAF into its new home\. Sign with the normal mode \(SIGHASH\_DEFAULT or ALL\)\. Any other mode can confirm on Bitcoin but move no LEAF\. ### 8. Why soft is still safe “Soft” does not mean weak\. Bitcoin fully enforces the wait and the signature, the only two guards on the way out\. The fingerprint gives the contract its identity: the same owner and wait with a different program makes a different address\. The CRC\-20 guide warns: never use a soft covenant as a deposit address\.