Keyless Signature Infrastructure (KSI) provides data integrity, timestamping, and verification without public/private keys. It works by having a service calculate hashes of data stored in the cloud each second and publish the hashes in a calendar database and newspaper. To check integrity later, one compares the stored hash value to the current one. However, simultaneous updates may go undetected, and an attacker could theoretically alter data and forge the published record if they compromised the cloud, hashing service, and newspaper. KSI aims to make public key infrastructure key management more efficient but has high computational costs for large datasets.