This publication seems to indicate that "Credential Service Provider" is analogous with "Identity Service Provider", but the definition provided for CSP doesn't align 1:1 with the ITU definition for IdSP [1]. The former assigns credentials, the latter may or may not assign credentials to individuals associated with such identities. A CSP seems to be an IdSP that only assigns identities to individuals whom have also been credentialed.
This publication seems to indicate that "Credential Service Provider" is analogous with "Identity Service Provider", but the definition provided for CSP doesn't align 1:1 with the ITU definition for IdSP [1]. The former assigns credentials, the latter may or may not assign credentials to individuals associated with such identities. A CSP seems to be an IdSP that only assigns identities to individuals whom have also been credentialed.