importprivkey "privkey" ( "label" ) ( rescan )

The importprivkey RPC adds a private key to your wallet. The key should be formatted in the wallet import format created by the `dumpprivkey` RPC.

*bitcoin-cli help importprivkey

importprivkey "privkey" ( "label" ) ( rescan )

Adds a private key (as returned by dumpprivkey) to your wallet. Requires a new wallet backup.
Hint: use importmulti to import more than one private key.

Arguments:
1. "privkey"          (string, required) The private key (see dumpprivkey)
2. "label"            (string, optional, default="") An optional label
3. rescan               (boolean, optional, default=true) Rescan the wallet for transactions

Note: This call can take over an hour to complete if rescan is true, during that time, other rpc calls
may report that the imported key exists but related transactions are still missing, leading to temporarily incorrect/bogus balances and unspent outputs until rescan completes.

Examples:

Dump a private key
> bitcoin-cli dumpprivkey "myaddress"

Import the private key with rescan
> bitcoin-cli importprivkey "mykey"

Import using a label and without rescan
> bitcoin-cli importprivkey "mykey" "testing" false

Import using default blank label and without rescan
> bitcoin-cli importprivkey "mykey" "" false

As a JSON-RPC call
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "importprivkey", "params": ["mykey", "testing", false] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/