Keychain password ***** ***** as the login or administrator password. Did you try those ? If they are not working, then try iCloud password.
If you don't remember it, then you can reset the password ***** booting into Mac OS X Utilities screen. If you are using 10.7 or later version of OS X, then follow the steps below to fix the issue (if you are using 10.6 or lower version or if this Mac is 6+ years old, then let me know as the instructions are slightly different)
Follow the steps below to reset the password.
Turn off your Mac by holding down the Power button for 5-10 seconds.
Turn it back on and immediately hold down Command and R keys at same time for 10 seconds.
This will boot your Mac to "Mac OS X Utilities” menu.
Click on the“Utilities” menu in top bar and select “Terminal".
In Terminal, type (without space)--> resetpassword
Press return. This will bring Reset Password ***** Select the hard disk at top column,select the user account from the drop down under it, confirm the user account and then change password ***** Save. Then click on the Apple icon and select Shutdown.
Turn it back on. After restarting, if you get any message about Keychain then click Create New Keychain.
If you are still getting keychain error, then reset the keychain access database. Follow the steps below to reset Keychain;
Go to System Preferences > iCloud and click Sign Out. If asked to keep or delete stuffs, click Keep. If you only see Delete, then do it. Then in Finder, hold down Option key on your keyboard, click on Go menu at the top bar and select Library. This will open Library folder. Trash Keychain folder in there and restart your Mac. Login with the password ***** reset.
Please let me know if that didn't work, so we can continue troubleshooting. If you face any issues, please let me know and I will walk you through it