Supported Algorithms

This page provides a high-level overview of algorithm support across the logical layers involved in EJBCA certificate signing. Detailed information about enrollment protocols, Certificate Authority (CA) types, and Hardware Security Module (HSM) support is documented in their respective documentation sections.

This overview is intended as a reference and may not always reflect the latest changes to individual features or components. In case of inconsistencies, the feature-specific or component-specific documentation is considered authoritative.

Supported Algorithms for Certificate Signing

EJBCA supports the following key algorithms, signature algorithms, and key specifications for certificate signing.

Note that HSM support depends on vendor implementation, firmware capabilities, and operational mode. Confirm with your HSM supplier that the required algorithms are supported in your target configuration, including FIPS mode where applicable. Operating an HSM in FIPS mode may impose additional restrictions, such as disallowing SHA1-based signature algorithms.

Key Algorithm / Key Specification	Signature Algorithm	Enrollment Protocol	CA Type	HSM Support
RSA (RSASSA-PKCS1_v1.5 and RSASSA-PSS) Security level: Security strength depends on key size. For comparison, RSA 2048 provides approximately 112-bit security, while RSA 3072 provides approximately 128-bit security.
Keys up to and including 8192 bits.	SHA1withRSA	ACME, EST, CMP, SCEP, REST Interface, Web Service Interface	X509 CA, CVC CA, SSH CA	Supported Hardware Security Modules (HSMs)
	SHA224withRSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA
	SHA256withRSA	ACME, EST, CMP, SCEP, REST Interface, Web Service Interface	X509 CA, CVC CA, SSH CA
	SHA384withRSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA
	SHA512withRSA	ACME, EST, CMP, SCEP, REST Interface, Web Service Interface	X509 CA, SSH CA
	SHA1withRSAandMGF1	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA, SSH CA
	SHA224withRSAandMGF1	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA
	SHA256withRSAandMGF1	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA, SSH CA
	SHA384withRSAandMGF1	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA
	SHA512withRSAandMGF1	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA
ECDSA Security level: Security strength depends on the selected curve. For comparison, P-256 provides approximately 128-bit security, while P-521 provides approximately 256-bit security.
Algorithm with named curves.	SHA1withECDSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA, SSH CA	Supported Hardware Security Modules (HSMs)
	SHA224withECDSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA
	SHA256withECDSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA
	SHA384withECDSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA
	SHA512withECDSA	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, CVC CA
EdDSA Security level: Ed25519 provides approximately 128-bit security, while Ed448 provides approximately 224-bit security.
Ed25519	Ed25519	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA	Supported Hardware Security Modules (HSMs)
Ed448	Ed448	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA, SSH CA	Supported Hardware Security Modules (HSMs)
ML-DSA Post-quantum cryptography (PQC) algorithms. Security level: ML-DSA-44 provides approximately 128-bit security, ML-DSA-65 provides a security level between 128 and 192 bits, and ML-DSA-87 provides approximately 256-bit security.
ML-DSA-44	ML-DSA-44	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA	AWS Key Management Service (KMS) Crypto4A QxHSM Entrust nShield Connect 5c Fortanix Data Security Manager (DSM) Thales Luna 7 Thales TCT Securosys Primus HSM and CloudHSM Service Utimaco u.trust Anchor
ML-DSA-65	ML-DSA-65	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87	ML-DSA-87	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA	ML-DSA-EXTERNAL-MU	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA	AWS Key Management Service (KMS) Thales Luna 7 Utimaco u.trust Anchor
ML-DSA Composite Post-quantum cryptography (PQC) algorithms. Composite signature schemes combine post-quantum and classical algorithms. Their effective security depends on the component algorithms and the composite signature construction.
ML-DSA-44 & RSA 2048	MLDSA44-RSA2048-PSS-SHA256	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA	AWS Key Management Service (KMS) Crypto4A QxHSM Entrust nShield Connect 5c Fortanix Data Security Manager (DSM) Thales Luna 7 Thales TCT Securosys Primus HSM and CloudHSM Service Utimaco u.trust Anchor
ML-DSA-44 & ECDSA	MLDSA44-ECDSA-P256-SHA256	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-44 & Ed25519	MLDSA44-Ed25519-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-65 & RSA 3072	MLDSA65-RSA3072-PSS-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-65 & RSA 4096	MLDSA65-RSA4096-PSS-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-65 & ECDSA	MLDSA65-ECDSA-P256-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-65 & ECDSA	MLDSA65-ECDSA-P384-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-65 & ECDSA	MLDSA65-ECDSA-brainpoolP256r1-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-65 & Ed25519	MLDSA65-Ed25519-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87 & RSA 3072	MLDSA87-RSA3072-PSS-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87 & RSA 4096	MLDSA87-RSA4096-PSS-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87 & ECDSA	MLDSA87-ECDSA-P384-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87 & ECDSA	MLDSA87-ECDSA-P521-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87 & ECDSA	MLDSA87-ECDSA-brainpoolP384r1-SHA512	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
ML-DSA-87 & Ed448	MLDSA87-Ed448-SHAKE256	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA Post-quantum cryptography (PQC) algorithms. Security level: Approximately 128-, 192-, or 256-bit security depending on the selected variant.
SLH-DSA	SLH-DSA-SHA2-128F	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA	Securosys Primus HSM and CloudHSM Service
SLH-DSA	SLH-DSA-SHA2-128S	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHA2-192F	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHA2-192S	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHA2-256F	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHA2-256S	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHAKE-128F	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHAKE-128S	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHAKE-192F	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHAKE-192S	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHAKE-256F	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA
SLH-DSA	SLH-DSA-SHAKE-256S	ACME, EST, CMP, REST Interface, Web Service Interface	X509 CA