How do the four eCH-0170 trust levels roughly map onto NIST SP 800-63, eIDAS and ISO/IEC 29115?

VS1 to NIST AAL1/IAL1/FAL1, no eIDAS level, ISO LoA1; VS2 to AAL1/FAL2, eIDAS low, LoA2; VS3 to AAL2/IAL2/FAL2, eIDAS substantial, LoA3; VS4 to AAL3/IAL3/FAL3, eIDAS high, LoA4.

This is the coarse comparison that eCH-0170 itself publishes; it warns that the mapping is approximate. Some reasons:

• eIDAS has only three levels. eIDAS "low" requires only one authentication factor, but it does demand at least one piece of evidence at registration and an internal audit, so eCH places it at VS2 rather than VS1.
• NIST has only three IALs, matching VS1, VS3 and VS4; there is no NIST counterpart for VS2 registration. NIST also does not accept an existing E-ID as identity evidence, which eCH-0170 does.
• Federation is a stand-alone model only in NIST (FAL) and eCH (VSF); eIDAS and ISO treat it as part of authentication.
• eCH-0170 V2.0.1 still compares against NIST 800-63-3; the July 2025 revision 800-63-4 changed details such as the FAL criteria and re-authentication timeouts.

Go deeper:

• eCH-0170 V2.0.1 — the full standard PDF, whose chapter 8 holds the comparison tables (in German).
• NIST SP 800-63-4: Select initial assurance levels — how NIST derives IAL, AAL and FAL from impact levels.