List of trusted certification authorities to communicate with CS OTE
When requesting the inclusion of an authority in the list of trusted qualified authorities by CS OTE, it is necessary for the authority's certificate to have the required identification for a qualified electronic signature or seal issuance service, in accordance with the EU eIDAS Regulation No. 910/2014.
The URI for identifying this service is http://uri.etsi.org/TrstSvc/TrustedList/SvcInfoExt/ForeSignatures. Alternatively, for creating electronic seals, the URI is http://uri.etsi.org/TrstSvc/TrustedList/SvcInfoExt/ForeSeals.
You can find more information here.
Supported Algorithms and Minimum Key Lengths
CS OTE supports certificates using RSA and ECDSA algorithms. For RSA, a minimum key length of 2048 bits is required; algorithms MD5 and SHA‑1 are not accepted. ECDSA certificates are supported with prime elliptic curves (e.g., NIST P‑256, P‑384, P‑521).
These requirements apply to access via the CS OTE web portal, the OTECOM application, and automatic communication.
The list is updated and valid as of 12/2025.
Certification Authority |
Supported certificate |
| První certifikační autorita, a.s. http://www.ica.cz  |
Qualified:
Commercial:
|
|
Česká pošta, s.p. (PostSignum)
http://www.postsignum.cz/  |
Qualified:
Commercial:
|
|
EIdentity a.s.
|
Qualified:
Commercial:
|
|
NetLock Ltd
 |
Qualified:
Commercial:
|
|
GLOBALTRUST
  |
Commercial:
|
|
DigiCert
  |
Commercial:
|
|
QuoVadis
|
Qualified:
Commercial:
|
|
ArubaPEC S.p.A.
  |
Qualified:
Commercial:
|
|
Asseco Data Systems S.A.
  |
Qualified:
Commercial:
|
|
Unizeto Sp. z o.o.
|
Qualified:
|
|
Krajowa Izba Rozliczeniowa S.A.,
|
Qualified:
|
|
EuroCert Sp. z o.o.
https://eurocert.pl/ |
Qualified:
|
|
Actalis S.p.A.
|
Qualified:
|
|
InfoCert S.p.A.,
|
Qualified:
Commercial:
|
|
POSTA SLOVENIJE d.o.o.
  |
Qualified:
|
|
Latvian State Radio and Television center
 |
Qualified:
|
|
GlobalSign
  |
Qualified:
Commercial:
|
|
Qualified:
|
|
|
InfoNotary PLC
 |
Qualified:
|
|
Microsec Ltd.
  |
Qualified:
Commercial:
|
|
D-Trust GmbH
 |
Commercial:
|
|
|
Qualified:
|
|
Buypass AS
|
Qualified:
|
|
Certigna
  |
Commercial:
|
|
Commercial:
|
|
|
COMODO CA Limited
  |
Commercial:
|
|
Sectigo Limited
|
Qualified:
Commercial:
|
|
Amazon
|
Commercial:
|
|
Let's Encrypt
|
Commercial:
|
|
GoDaddy Inc.
|
Commercial:
|
