Statements on Auditing Standards (SAS) 70 is a US standard and originated in April 1992 for reporting on controls. SAS 70, is a widely recognized auditing standard developed by the American Institute of Certified Public Accountants (AICPA).
International Standard on Assurance Engagements ISAE 3402, was issued in December 2009, by the International Auditing and Assurance Standards Board (IAASB). ISAE 3402 is an international standard on Service Organization Reporting.
Statement on Standards for Attestation Engagements (SSAE) No. 16, was issued in January 2010, by the American Institute of Certified Public Accountants (AICPA) Auditing Standards Board. SSAE is US Standard on Service Organization Reporting. SSAE 16 is quite similar to the other two standards and include changes for Service Organizations to provide better customer services.