Keyless Signature Infrastructure (KSI) is a web-scale digital signature/timestamp system for electronic data. The term ‘keyless’ denotes that the signatures can be reliably verified without assuming secrecy of cryptographic keys. Keyless signatures are not vulnerable to key compromise implying that their lifetime is based only on the security properties of the cryptographic hash function and also that their security properties will survive intact when practical quantum computing becomes a reality.


Please refer to materials and code below for an overview of the KSI format.

Guardtime SDK for C (libgt)
For integrating KSI into C and C++ based applications. The SDK contains libraries to obtain signatures from the KSI Gateways and later use the signature to authenticate the signed data.
Contributed by: Guardtime
License: Apache 2.0
Downloads: libgt source (@guardtime) | libgt documentation (@guardtime)

Command line utility for accessing KSI services
Contributed by: Risto Laanoja
License: Apache 2.0
Downloads: gtime (@github)


contact for this page: Ahto Buldas ahto@openksi.org