RSA_VERIFY_HASH()

Procedural SQL (PSQL) StatementsAggregate Functions

`RSA_VERIFY_HASH()`

Verifies a message hash against a signature using an RSA public key

Result type

BOOLEAN

Syntax

RSA_VERIFY_HASH (message_digest
  SIGNATURE signature KEY public_key
  [HASH <hash>] [SALT_LENGTH salt_length]
  [PKCS_1_5])

<hash> ::= MD5 | SHA1 | SHA256 | SHA512

Table 1. `RSA_VERIFY` Function Parameters
Parameter	Description
message_digest	Hash of message to verify.The hash algorithm used should match hash
signature	Expected signature of input generated by `RSA_SIGN_HASH`
public_key	RSA public key in PKCS#1 format matching the private key used to sign
hash	Hash to use for the message digest;default is `SHA256`.This should be the same hash as used to generate message_digest, and as used in `RSA_SIGN_HASH`
salt_length	Length of the salt in bytes;default is 8;minimum 1, maximum 32.Value must match the length used in `RSA_SIGN_HASH`.

RSA_VERIFY_HASH performs PSS encoding of the message_digest to be verified, and verifies the digital signature using the provided RSA public key.

By default, OAEP padding is used.The PKCS_1_5 option will switch to the less secure PKCS 1.5 padding.

Warning

The PKCS_1_5 option is only for backward compatibility with systems applying PKCS 1.5 padding.For security reasons, it should not be used in new projects.

Caution

This function expects the hash of a message (or message digest), not the actual message.The hash argument should specify the algorithm that was used to generate that hash.

A function that accepts the actual message to hash might be introduced in a future version of Firebird.

`RSA_VERIFY_HASH` Examples

Tip	Run the examples of the `RSA_PRIVATE`, `RSA_PUBLIC` and `RSA_SIGN_HASH` functions first.

select rsa_verify_hash(
  crypt_hash('Test message' using sha256)
  signature rdb$get_context('USER_SESSION', 'msg')
  key rdb$get_context('USER_SESSION', 'public_key'))
from rdb$database

RSA_VERIFY_HASH()

RSA_VERIFY_HASH()

RSA_VERIFY_HASH Examples

`RSA_VERIFY_HASH()`

`RSA_VERIFY_HASH` Examples