READ THIS AND DON'T PANIC ! >> https://support.apple.com/en-us/102651
The word's "DON'T PANIC" were written large and in bold on The Hitchhikers Guide To The Galaxy.
iCloud uses strong security methods, employs strict policies to protect your information, and leads the industry in using privacy-preserving security technologies like end-to-end encryption for your data.
iCloud data security and encryptionThe security of your data in iCloud starts with the security of your Apple Account. All new Apple Accounts require two-factor authentication to help protect you from fraudulent attempts to gain access to your account. Two-factor authentication is also required for many features across Apple’s ecosystem, including end-to-end encryption.
Apple offers two options to encrypt and protect the data you store in iCloud:
Standard data protection is the default setting for your account. Your iCloud data is encrypted, the encryption keys are secured in Apple data centers so we can help you with data recovery, and only certain data is end-to-end encrypted.
In the USA and elsewhere, you can switch on this...
Advanced Data Protection for iCloud is an optional setting that offers our highest level of cloud data security. If you choose to enable Advanced Data Protection, your trusted devices retain sole access to the encryption keys for the majority of your iCloud data, thereby protecting it using end-to-end encryption. Additional data protected includes iCloud Backup, Photos, Notes, and more.
Advanced Data Protection for iCloud is an optional setting that offers our highest level of cloud data security. If you choose to enable Advanced Data Protection, your trusted devices retain sole access to the encryption keys for the majority of your iCloud data, thereby protecting it using end-to-end encryption. Additional data protected includes iCloud Backup, Photos, Notes, and more.
So DON'T PANIC (yet, until the data breaches take place and you can sue the government !)