Botan::PSS_Params Class Reference

#include <pss_params.h>

Inheritance diagram for Botan::PSS_Params:

Public Member Functions
std::vector< uint8_t >	BER_encode () const
void	encode_into (DER_Encoder &to) const override
const AlgorithmIdentifier &	hash_algid () const
std::string	hash_function () const
const AlgorithmIdentifier &	mgf_algid () const
std::string	mgf_function () const
const AlgorithmIdentifier &	mgf_hash_algid () const
BOTAN_FUTURE_EXPLICIT	PSS_Params (std::span< const uint8_t > der)
	PSS_Params (std::string_view hash_fn, size_t salt_len)
size_t	salt_length () const
std::vector< uint8_t >	serialize () const
size_t	trailer_field () const

Static Public Member Functions
static PSS_Params	from_emsa_name (std::string_view padding_name)
static PSS_Params	from_padding_name (std::string_view padding_name)

Detailed Description

PSS parameters type

Handles encoding/decoding of RSASSA-PSS-params from RFC 3447

Only MGF1 is supported, and the trailer field must 1 (ie the variant from IEEE 1363a using a hash identifier is not supported)

Definition at line 24 of file pss_params.h.

Constructor & Destructor Documentation

PSS_Params() [1/2]

Botan::PSS_Params::PSS_Params	(	std::string_view	hash_fn,
		size_t	salt_len )

Create PSS parameters using MGF1 with the same hash as the message hash

Parameters

hash_fn	the name of the hash function to use
salt_len	the salt length in bytes

Definition at line 32 of file pss_params.cpp.

                                                              :
      m_hash(hash_fn, AlgorithmIdentifier::USE_NULL_PARAM),
      m_mgf("MGF1", m_hash.BER_encode()),
      m_mgf_hash(m_hash),
      m_salt_len(salt_len),
      m_trailer_field(1) {}

References Botan::ASN1_Object::BER_encode().

Referenced by from_emsa_name(), and from_padding_name().

PSS_Params() [2/2]

Botan::PSS_Params::PSS_Params

(

std::span< const uint8_t >

der

)

Decode an encoded RSASSA-PSS-params

Definition at line 39 of file pss_params.cpp.

                                                 : m_salt_len(0), m_trailer_field(1) {
   BER_Decoder decoder(der, BER_Decoder::Limits::DER());
   this->decode_from(decoder);
   decoder.verify_end();
}

References Botan::BER_Decoder::Limits::DER(), and Botan::BER_Decoder::verify_end().

Member Function Documentation

BER_encode()

std::vector< uint8_t > Botan::ASN1_Object::BER_encode ( ) const

inherited

Return the encoding of this object. This is a convenience method when just one object needs to be serialized. Use DER_Encoder for complicated encodings.

Definition at line 21 of file asn1_obj.cpp.

                                                 {
   std::vector<uint8_t> output;
   DER_Encoder der(output);
   this->encode_into(der);
   return output;
}

References encode_into().

Referenced by decode_from(), Botan::PKCS12::export_to(), Botan::Certificate_Store_In_SQL::find_all_certs(), Botan::Certificate_Store_In_SQL::find_cert(), Botan::X509_Certificate::fingerprint(), Botan::Certificate_Store_In_SQL::insert_cert(), Botan::X509_Object::PEM_encode(), and Botan::PSS_Params::PSS_Params().

encode_into()

void Botan::PSS_Params::encode_into ( DER_Encoder & to ) const

overridevirtual

Encode whatever this object is into to

Parameters

to	the DER_Encoder that will be written to

Implements Botan::ASN1_Object.

Definition at line 51 of file pss_params.cpp.

                                                  {
   to.start_sequence()
      .start_context_specific(0)
      .encode(m_hash)
      .end_cons()
      .start_context_specific(1)
      .encode(m_mgf)
      .end_cons()
      .start_context_specific(2)
      .encode(m_salt_len)
      .end_cons()
      .end_cons();
}

References Botan::DER_Encoder::encode(), Botan::DER_Encoder::end_cons(), Botan::DER_Encoder::start_context_specific(), and Botan::DER_Encoder::start_sequence().

from_emsa_name()

PSS_Params Botan::PSS_Params::from_emsa_name ( std::string_view padding_name )

inlinestatic

Note that the only valid strings you can pass to this function are values returned by SignaturePaddingScheme::name() and these may change in a minor release.

Definition at line 39 of file pss_params.h.

                                                                    {
         return PSS_Params::from_padding_name(padding_name);
      }

References from_emsa_name(), from_padding_name(), and PSS_Params().

Referenced by from_emsa_name().

from_padding_name()

PSS_Params Botan::PSS_Params::from_padding_name ( std::string_view padding_name )

static

Note that the only valid strings you can pass to this function are values returned by SignaturePaddingScheme::name() and these may change in a minor release.

Definition at line 19 of file pss_params.cpp.

                                                                    {
   const SCAN_Name scanner(padding_name);
 
   if((scanner.algo_name() != "PSS" && scanner.algo_name() != "PSS_Raw") || scanner.arg_count() != 3) {
      throw Invalid_Argument(fmt("PSS_Params::from_padding_name unexpected param '{}'", padding_name));
   }
 
   const std::string hash_fn = scanner.arg(0);
   BOTAN_ARG_CHECK(scanner.arg(1) == "MGF1", "PSS requires MGF1");
   const size_t salt_len = scanner.arg_as_integer(2);
   return PSS_Params(hash_fn, salt_len);
}

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_as_integer(), Botan::SCAN_Name::arg_count(), BOTAN_ARG_CHECK, Botan::fmt(), and PSS_Params().

Referenced by from_emsa_name().

hash_algid()

const AlgorithmIdentifier & Botan::PSS_Params::hash_algid ( ) const

inline

Return the AlgorithmIdentifier of the hash used to hash the message

Definition at line 59 of file pss_params.h.

{ return m_hash; }

Referenced by hash_function().

hash_function()

std::string Botan::PSS_Params::hash_function ( ) const

inline

Return the name of the hash used to hash the message

Definition at line 84 of file pss_params.h.

{ return hash_algid().oid().to_formatted_string(); }

References hash_algid().

mgf_algid()

const AlgorithmIdentifier & Botan::PSS_Params::mgf_algid ( ) const

inline

Return the AlgorithmIdentifier of the mask generation function

Definition at line 64 of file pss_params.h.

{ return m_mgf; }

Referenced by mgf_function().

mgf_function()

std::string Botan::PSS_Params::mgf_function ( ) const

inline

Return the name of the mask generation function; only MGF1 is supported

Definition at line 89 of file pss_params.h.

{ return mgf_algid().oid().to_formatted_string(); }

References mgf_algid().

mgf_hash_algid()

const AlgorithmIdentifier & Botan::PSS_Params::mgf_hash_algid ( ) const

inline

Return the AlgorithmIdentifier of the hash used within the mask generation function

Definition at line 69 of file pss_params.h.

{ return m_mgf_hash; }

salt_length()

size_t Botan::PSS_Params::salt_length ( ) const

inline

Return the salt length in bytes

Definition at line 74 of file pss_params.h.

{ return m_salt_len; }

serialize()

std::vector< uint8_t > Botan::PSS_Params::serialize

(

)

const

Return the DER encoding of these RSASSA-PSS-params

Definition at line 45 of file pss_params.cpp.

                                               {
   std::vector<uint8_t> output;
   DER_Encoder(output).encode(*this);
   return output;
}

References Botan::DER_Encoder::encode().

trailer_field()

size_t Botan::PSS_Params::trailer_field ( ) const

inline

Return the trailer field; only a value of 1 is supported

Definition at line 79 of file pss_params.h.

{ return m_trailer_field; }

---

The documentation for this class was generated from the following files:

• src/lib/asn1/pss_params.h
• src/lib/asn1/pss_params.cpp