Appendix A
Minimum Cryptographic Algorithm and Key Size Requirements
Certificates and Timestamp tokens issued after the effective date of these guidelines MUST meet the following requirements for algorithm type and key size.
(1) Code Signing Root, Subordinate CA, and Code Signing Certificates
The table below defines cryptographic requirements for Code Signing Certificates issued within the specified time and their corresponding Root Certificates and Subordinate CA Certificates.
Note: The digest algorithm used to issue the Root Certificate does not have security relevance and need not conform to the requirements in the table below.
Code Signing Certificates issued prior to January 1, 2021and their corresponding Root Certificates and Subordinate CA Certificates
Code Signing Certificates issued on or after January 1, 2021 and their corresponding Root Certificates and Subordinate CA Certificates
Digest algorithm
SHA-256, SHA-384 or SHA-512 (SHA-1 for legacy implementations only)*
SHA-256, SHA-384 or SHA-512
Minimum RSA modulus size (bits)
2048
3072
ECC curve
NIST P-256, P-384, or P-521
NIST P-256, P-384, or P-521
Minimum DSA modulus and divisor size (bits)
L= 2048, N= 224 or L= 2048, N=256
L= 2048, N= 224 or L= 2048, N= 256
*CAs can issue SHA-1 certificates to legacy platforms that do not support SHA-2 only for code signing and timestamping certificates.
(2) Timestamp Root, Subordinate CA, and Timestamp Certificates
The table below defines cryptographic requirements for Timestamp Certificates issued within the specified time and their corresponding Root Certificates and Subordinate CA Certificates.
Note: The digest algorithm used to issue the Root Certificate does not have security relevance and need not conform to the requirements in the table below.
Timestamp Certificates issued prior to January 1, 2021 and their corresponding Root Certificates and Subordinate CA Certificates
Timestamp Certificates issued on or after January 1, 2021 and their corresponding Root Certificates and Subordinate CA Certificates
Digest algorithm
SHA-256, SHA-384 or SHA-512 (SHA-1 for legacy implementations only)*
SHA-256, SHA-384 or SHA-512
Minimum RSA modulus size (bits)
2048
3072
ECC curve
NIST P-256, P-384, or P-521
NIST P-256, P-384, or P-521
Minimum DSA modulus and divisor size (bits)
L= 2048, N= 224 or L= 2048, N=256
L= 2048, N= 224 or L= 2048, N= 256
*CAs can issue SHA-1 certificates to legacy platforms that do not support SHA-2 only for code signing and timestamping certificates.
(3) Timestamp Tokens
The digest algorithms used to sign Timestamp tokens must match the digest algorithm used to sign the Timestamp Certificate.
Generated prior to January 1, 2021
Generated on or after January 1, 2021
Digest algorithm
SHA-256, SHA-384 or SHA-512 (SHA-1 for legacy implementations only)*
SHA-256, SHA-384 or SHA-512
*CAs can issue SHA-1 certificates to legacy platforms that do not support SHA-2 only for code signing and timestamping certificates.