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Also known as: RSA Probabilistic Signature Scheme
A probabilistic RSA signature scheme providing strong security by salting and MGF1, recommended over deterministic PKCS#1 v1.5 signatures.
DESCRIPTION
RSA-PSS (RSASSA-PSS) is the modern RSA signature scheme defined in PKCS #1 (RFC 8017). It uses a random salt and MGF1 to achieve provable security properties under standard assumptions. RSA-PSS is widely recommended in modern standards and supported by libraries and PKI. Correct parameter alignment (hash and salt length) and side-channel resistant implementations are critical. RSASSA-PKCS1-v1_5 is considered legacy compared to PSS.
ALTERNATIVE DEFINITIONS
IETF RFC 8017 (PKCS #1 v2.2)
RSASSA-PSS: RSA Signature Scheme with Appendix - Probabilistic Signature Scheme.
Normative specification title describing the RSA-PSS signature scheme.
NIST
RSASSA-PSS is a method for generating and verifying RSA signatures that adds a random salt to provide additional security.
Emphasizes the role of a random salt in RSA-PSS security.
Wikipedia
In cryptography, a probabilistic signature scheme is a type of digital signature by which, on each signature generation, the signer includes a random value.
Provides the general context for probabilistic signatures including RSA-PSS.
RELATED TERMS
RSA PKCS #1 Digital Signature Hash Function MGF1 Salt Certificate FIPS 186-5 NIST SP 800-186 Asymmetric Encryption
COMPETING TERMS
RSASSA-PKCS1-v1_5
KNOWLEDGE AREAS
Data Security Data Privacy & Compliance Infrastructure
TARGET AUDIENCE
Security Architect Cybersecurity Engineer Software Developer Chief Information Security Officer IT Auditor
EXTERNAL SOURCES
- Wikipedia - RSASSA-PSS
- IETF - PKCS #1 v2.2 signature specifications
- NIST - Digital Signature Standard (DSS) guidance
TOP QUESTIONS
Why is RSA-PSS preferred over RSASSA-PKCS1-v1_5?
PSS provides stronger security proofs and uses randomness (salt), reducing certain attack surfaces present in deterministic v1_5 signatures.
Category: Opinion
What parameters matter in RSA-PSS?
Hash function, MGF1 hash, and salt length must be consistently set across systems to ensure interoperability and security.
Category: Requirements
Where is RSA-PSS commonly used?
In modern PKI, code signing, and protocols that adopt stronger RSA signature schemes by default.
Category: Overview
What are common mistakes with RSA-PSS?
Mismatched parameters across systems, improper salt handling, and timing leaks in verification procedures.
Category: Mistakes
Is RSA-PSS quantum-safe?
No; RSA-based schemes are vulnerable to quantum attacks. Consider post-quantum signatures for long-term security.
Category: Risks
How does RSA-PSS achieve better security?
Random salting and MGF1 produce probabilistic signatures that thwart certain forgery strategies and strengthen security proofs.
Category: Example
Does RSA-PSS work with existing certificate infrastructures?
Yes, many CAs and libraries support PSS; ensure algorithms and parameters are declared in certificates.
Category: Management
What standards specify RSA-PSS?
PKCS #1 (RFC 8017) and FIPS 186-5 provide normative definitions and guidance.
Category: Overview
How should systems migrate to RSA-PSS?
Audit compatibility, align parameters, update libraries, and test interoperability with partners and CAs.
Category: Requirements