LibItsSecurity_Functions.ttcn3

/**
 *  @author   ETSI / STF481
 *  @version  $URL$
 *            $Id$
 *  @desc     Module containing functions for Security Protocol
 *
 */
module LibItsSecurity_Functions {
    
    // Libcommon
    import from LibCommon_BasicTypesAndValues all;
    import from LibCommon_DataStrings all;

    // LibItsCommon
    import from LibItsCommon_Functions all;
    
    // LibItsSecurity
    import from LibItsSecurity_TypesAndValues all;
    import from LibItsSecurity_Templates all;
    import from LibItsSecurity_Pixits all;
    import from LibItsSecurity_TestSystem all;
    
    group helpersFunctions {
        
        /**
        * @desc    Produces a 256-bit (32-byte) hash value
        * @param   p_toBeHashedData Data to be used to calculate the hash value
        * @return  The hash value
        */
        function f_hashWithSha256(
                                  in octetstring p_toBeHashedData
        ) return Oct32 {
            return fx_hashWithSha256(p_toBeHashedData);
        } // End of function f_hashWithSha256
        
        /**
        * @desc    Produces a Elliptic Curve Digital Signature Algorithm (ECDSA) signaturee
        * @param   p_toBeSignedSecuredMessage    The data to be signed
        * @return  The signature value
        */
        function f_signWithEcdsaNistp256WithSha256(
                                                   in Oct32 p_toBeSignedSecuredMessage
        ) runs on ItsSecurityBaseComponent return octetstring {
            return fx_signWithEcdsaNistp256WithSha256(
                p_toBeSignedSecuredMessage,
                vc_signingPrivateKey
            );
            
        } // End of function f_signWithEcdsaNistp256WithSha256
        
        /**
        * @desc Compute the HashedId8 value from the hash value
        * @param p_hash The hash value
        * @return The HashedId8 value
        * @verdict
        */
        function f_HashedId8FromSha256(
                                       in Oct32 p_hash
        ) return HashedId8 {
            return substr(p_hash, lengthof(p_hash) - 8, 8);
        } // End of function f_HashedId8FromSha256
        
        /**
        * @desc Compute the HashedId3 value from the HashedId8 value
        * @param p_hashp_hashedId8 The HashedId8 value
        * @return The HashedId3 value
        * @verdict Unchanged
        */
        function f_HashedId3FromHashedId8(
                                          in HashedId8 p_hashedId8
        ) return HashedId3 {
            return substr(p_hashedId8, lengthof(p_hashedId8) - 3, 3);
        }  // End of function f_HashedId3FromHashedId8
        
        /**
        * @desc    Verify the signature of the specified data
        * @param   p_toBeVerifiedData          The data to be verified
        * @param   p_signature                 The signature
        * @param   p_ecdsaNistp256PublicKeyX   The public key (x coordinate)
        * @param   p_ecdsaNistp256PublicKeyY   The public key (y coordinate)
        * @return  true on success, false otherwise
        */
        function f_verifyWithEcdsaNistp256WithSha256(
                                                     in octetstring p_toBeVerifiedData,
                                                     in octetstring p_signature,
                                                     in octetstring p_ecdsaNistp256PublicKeyX,
                                                     in octetstring p_ecdsaNistp256PublicKeyY
        ) return boolean {
            return fx_verifyWithEcdsaNistp256WithSha256(
                p_toBeVerifiedData,
                p_signature,
                p_ecdsaNistp256PublicKeyX,
                p_ecdsaNistp256PublicKeyY);
        } // End of function f_verifyWithEcdsaNistp256WithSha256
        
        /**
        * @desc    Calculate digest over the certificate
        * @param   p_cert The certificate
        * @return  the HashedId8 value
        * @see Draft ETSI TS 103 097 V1.1.14 Clause 4.2.13   HashedId8
        */
        function f_calculateDigestFromCertificate(
                                                  in Certificate p_cert
        ) return HashedId8 {
            var octetstring v_toBeHashedData;
            var octetstring v_hash;
                        
            v_toBeHashedData := bit2oct(encvalue(p_cert));
            v_hash := f_hashWithSha256(v_toBeHashedData);
            return substr(v_hash, lengthof(v_hash) - 8, 8);
        } // End of function f_calculateDigestFromCertificate
        
        group hostSignatureHelpers {
            
            /**
            * @desc    Initialize [out] certificates according to the specified certificate name
            * @param   p_certificateName The certificate name to be used
            * @param   p_aaCertificate The AA certificate [out]
            * @param   p_atCertificate The AT certificate [out]
            * @return  true on succes, false otherwise
            * @see Draft ETSI TS 103 097 V1.1.14 Clause 4.2.13   HashedId8
            */
            function f_prepareCertificates(
                                           in template (omit) charstring p_certificateName,
                                           out Certificate p_aaCertificate,
                                           out Certificate p_atCertificate
            ) runs on ItsSecurityBaseComponent return boolean {
                
                // Load certificates if required
                if (ispresent(p_certificateName) and (valueof(p_certificateName) != cc_taCertA)) {
                    if (f_readCertificate(valueof(p_certificateName) & ".AA_CERT", p_aaCertificate) == false) {
                        return false;
                    }
                    if (f_readCertificate(valueof(p_certificateName) & ".AT_CERT", p_atCertificate) == false) {
                        return false;
                    }
                } else {
                    p_aaCertificate := vc_aaCertificate;
                    p_atCertificate := vc_atCertificate;
                }
                // Store the certificte to build this message
                vc_lastAtCertificateUsed := p_atCertificate;
                
                return true;
            } // End of function f_prepareCertificates
            
            /**
            * @desc Build a template of a secured beacon to be used for the Test Adapter secured beaconing processing
            */
            function f_buildSecuredMessagePayloadToBeSigned(
                                                            in boolean p_includeCertificate := false
            ) runs on ItsSecurityBaseComponent return ToBeSignedSecuredMessage {
                
                // Local variables
                var template (value) ToBeSignedSecuredMessage v_toBeSignedSecuredMessage;
                
                // Build the beacon template
                if (p_includeCertificate == true) {
                    v_toBeSignedSecuredMessage := m_toBeSignedSecuredMessage(
                        { // Field HeaderFields
                            m_header_field_signer_info(
                                m_signerInfo_certificate(
                                    vc_atCertificate
                                ) // End of template m_signerInfo_certificate
                            ), // End of template m_header_field_signer_info
                            m_header_field_generation_time(oct2int('BBBBBBBB'O)),   // To be replaced by TA with generation time
                            m_header_field_generation_location(
                                vc_location
                            )
                        }, // End of field HeaderFields
                        m_payload_signed(
                            'AAAAAAAAAA'O                                           // To be replaced by TA with real payload
                        ),
                        e_signature
                    );
                } else {
                    v_toBeSignedSecuredMessage := m_toBeSignedSecuredMessage(
                        { // Field HeaderFields
                            m_header_field_signer_info(
                                m_signerInfo_digest(
                                    vc_atCertificate.signer_info.signerInfo.digest
                                ) // End of template m_signerInfo_certificate
                            ), // End of template m_header_field_signer_info
                            m_header_field_generation_time(oct2int('BBBBBBBB'O)),   // To be replaced by TA with generation time
                            m_header_field_generation_location(
                                vc_location
                            )
                        }, // End of field HeaderFields
                        m_payload_signed(
                            'AAAAAAAAAA'O                                           // To be replaced by TA with real payload
                        ),
                        e_signature
                    );
                }
                
                return valueof(v_toBeSignedSecuredMessage);
            }
            
            /**
             * @desc  This function build and sign the SecureMessage part covered by the signature process
             * @param p_securedMessage      The signed  SecureMessage part
             * @param p_payloadField       Payloads to be included in the message
             * @param p_mandatoryHeaders    Mandatory headers for the selected profile 
             * @param p_headerFields        HeaderFields to be inserted in the message
             * @param p_securityProfile     Selected security profile
             * @return true on success, false otherwise
             */
            function f_buildGnSecuredMessage(
                                             out template (value) SecuredMessage p_securedMessage,
                                             in template (value) SecPayload p_payloadField,
                                             in template (value) HeaderFields p_mandatoryHeaders,
                                             in template (omit) HeaderFields p_headerFields := omit
            ) runs on ItsSecurityBaseComponent return boolean {
                
                // Local variables
                var octetstring v_secPayload, v_signature;
                var Oct32 v_hash;
                var template (value) ToBeSignedSecuredMessage v_toBeSignedSecuredMessage;
                var integer i, j, k, n;
                var HeaderFields v_headerFields := {};
                var SecPayload v_toBeSignedPayload;
                
                // Prepare headers
                if (not(ispresent(p_headerFields))) {
                    v_headerFields := valueof(p_mandatoryHeaders);
                } else {
                    // Merge p_headerFields and v_mandatoryHeaders into v_headerFields
                        
                    i := 0; // index for p_headerFields
                    j := 0; // index for v_mandatoryHeaders
                    k := 0; // index for v_headerFields
                        
                    // Special processing for signer_info
                    if (lengthof(valueof(p_headerFields)) > 0 and valueof(p_headerFields[i].type_) == e_signer_info) {
                        v_headerFields[k] := valueof(p_headerFields[i]);
                        k := k + 1;
                        i := i + 1;
                    }
                    
                    for (j := j; j < lengthof(p_mandatoryHeaders); j := j + 1) {
                        // Search for mandatory header in p_HeaderFields
                        for (n := 0; n < lengthof(p_headerFields); n := n + 1) {
                            if (valueof(p_headerFields[n].type_) == valueof(p_mandatoryHeaders[j].type_)) {
                                // mandatory header already in p_HeaderFields
                                break;
                            }
                        } // End of 'for' statement
                        if (n >= lengthof(p_headerFields)) {
                            if (valueof(p_mandatoryHeaders[j].type_) != e_signer_info) {
                                // Add headers from p_headerFields having lower number than mandatory header
                                for (n := i; n < lengthof(p_headerFields) and valueof(p_headerFields[n].type_) < valueof(p_mandatoryHeaders[j].type_); n := n + 1) {
                                    v_headerFields[k] := valueof(p_headerFields[n]);
                                    k := k + 1;
                                    i := i + 1;
                                }
                            }
                            // Add mandatory header
                            v_headerFields[k] := valueof(p_mandatoryHeaders[j]);
                            k := k + 1;
                        }
                    } // End of 'for' statement
                        
                    // Add remaining headers from p_HeaderFields
                    for ( i := i; i < lengthof(p_headerFields); i := i + 1) {
                        // Add headers from p_headerFields having lower number than mandatory header
                        v_headerFields[k] := valueof(p_headerFields[i]);
                        k := k + 1;
                    } // End of 'for' statement
                }
                
                // Prepare payload to be signed
                if (
                    (valueof(p_payloadField.type_) == e_signed) or 
                    (valueof(p_payloadField.type_) == e_signed_and_encrypted
                )) {
                    v_toBeSignedPayload := valueof(p_payloadField);
                } // TODO else, check draft
                
                v_toBeSignedSecuredMessage := m_toBeSignedSecuredMessage(
                    v_headerFields,
                    v_toBeSignedPayload,
                    e_signature
                );
                
                v_secPayload := bit2oct(encvalue(v_toBeSignedSecuredMessage));
                
                // Calculate the hash of the SecuredMessage payload to be signed
                v_hash := f_hashWithSha256(v_secPayload);
                
                // Signed payload
                v_signature := f_signWithEcdsaNistp256WithSha256(
                    v_hash
                );
                
                p_securedMessage := m_securedMessage(
                    v_toBeSignedSecuredMessage.header_fields,
                    p_payloadField,
                    {
                        m_trailer_field_signature(
                            m_signature(
                                m_ecdsaSignature(
                                    m_eccPointecdsa_nistp256_with_sha256_y_coordinate_only(
                                        substr(v_signature, 2, 32)
                                    ),
                                    substr(v_signature, 34, 32)
                                )
                            )
                        )
                    }
                );
                
                return true;
            }
            
            /**
            * @desc This function build and sign the SecureMessage part covered by the signature process
            * @param p_securedMessage       The signed  SecureMessage part
            * @param p_payloadField         Payloads to be included in the message
            * @param p_signerInfoType       Add digest or AT certificate or certificate chain
            * @param p_threeDLocation       The 3D location
            * @param p_headerFields         HeaderFields to be inserted in the message
            * @param p_certificateName      The certificate identifier to be used. Default: TA_CERT_A
            * @param p_addMissingHeaders    Whether to add mandatory headers not present in p_headerFields
            * @return true on success, false otherwise
            * 
            * @see Draft ETSI TS 103 097 V1.1.14 Clause 7.1  Security profile for CAMs
            */
            function f_buildGnSecuredCam(
                                         out template (value) SecuredMessage p_securedMessage,
                                         in template (value) SecPayload p_payloadField,
                                         in template (omit) SignerInfoType p_signerInfoType := e_certificate_digest_with_sha256,
                                         in template (omit) HeaderFields p_headerFields := omit,
                                         in template (omit) charstring p_certificateName := omit,
                                         in boolean p_addMissingHeaders := true
            ) runs on ItsSecurityBaseComponent return boolean {
                
                // Local variables
                var Certificate v_aaCertificate, v_atCertificate;
                var HeaderFields v_mandatoryHeaders := {};
                var HeaderField v_signerInfo;
                 
                // Load certificates if required
                if (f_prepareCertificates(p_certificateName, v_aaCertificate, v_atCertificate) == false) {
                    return false;
                }
                
                if (p_addMissingHeaders == true) {
                    // Prepare mandatory headers
                    if (valueof(p_signerInfoType) == e_certificate) { // Add the AT certificate
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_certificate(
                                    v_atCertificate
                        )));
                    }
                    if (valueof(p_signerInfoType) == e_certificate_chain) { // Add the AT certificate + AA Certificate
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_certificates(
                                    {
                                        v_aaCertificate,
                                        v_atCertificate
                                    }
                                )
                        ));
                    }
                    if (valueof(p_signerInfoType) == e_certificate_digest_with_sha256) { // Add the AT certificate digest
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_digest(
                                    v_atCertificate.signer_info.signerInfo.digest
                        )));
                    }
                    v_mandatoryHeaders := {
                        v_signerInfo,
                        valueof(m_header_field_generation_time(1000 * f_getCurrentTime())), // In us
                        valueof(m_header_field_its_aid(c_its_aid_CAM))
                    }
                }
                
                return f_buildGnSecuredMessage(p_securedMessage, p_payloadField, v_mandatoryHeaders, p_headerFields);
                
            } // End of function f_buildGnSecuredCam

            /**
            * @desc This function build and sign the SecureMessage part covered by the signature process
            * @param p_securedMessage       The signed  SecureMessage part
            * @param p_payloadField        Payloads to be included in the message
            * @param p_signerInfoType       Add digest or AT certificate or certificate chain
            * @param p_threeDLocation       The 3D location
            * @param p_headerFields         HeaderFields to be inserted in the message
            * @param p_certificateName      The certificate identifier to be used. Default: TA_CERT_A
            * @param p_addMissingHeaders    Whether to add mandatory headers not present in p_headerFields
            * @return true on success, false otherwise
            */
            function f_buildGnSecuredDenm(
                                          out template (value) SecuredMessage p_securedMessage,
                                          in template (value) SecPayload p_payloadField,
                                          in template (omit) SignerInfoType p_signerInfoType := e_certificate_digest_with_sha256,
                                          in ThreeDLocation p_threeDLocation,
                                          in template (omit) HeaderFields p_headerFields := omit,
                                          in template (omit) charstring p_certificateName := omit,
                                          in boolean p_addMissingHeaders := true
            ) runs on ItsSecurityBaseComponent return boolean {
                
                // Local variables
                var Certificate v_aaCertificate, v_atCertificate;
                var HeaderFields v_mandatoryHeaders := {};
                var HeaderField v_signerInfo;
                 
                // Load certificates if required
                if (f_prepareCertificates(p_certificateName, v_aaCertificate, v_atCertificate) == false) {
                    return false;
                }
                
                // Add additional headers if required
                if (p_addMissingHeaders == true) {
                    // Prepare mandatory headers
                    if (valueof(p_signerInfoType) == e_certificate) { // Add the AT certificate
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_certificate(
                                    v_atCertificate
                        )));
                    }
                    if (valueof(p_signerInfoType) == e_certificate_chain) { // Add the AT certificate + AA Certificate
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_certificates(
                                    {
                                        v_aaCertificate,
                                        v_atCertificate
                                    }
                                )
                        ));
                    }
                    if (valueof(p_signerInfoType) == e_certificate_digest_with_sha256) { // Add the AT certificate digest
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_digest(
                                    v_atCertificate.signer_info.signerInfo.digest
                        )));
                    }
                    v_mandatoryHeaders := {
                        v_signerInfo,
                        valueof(m_header_field_generation_time(1000 * f_getCurrentTime())), // In us
                        valueof(m_header_field_generation_location(p_threeDLocation)),
                        valueof(m_header_field_its_aid(c_its_aid_DENM))
                    }
                }
                
                // Build the secured message and return it
                return f_buildGnSecuredMessage(p_securedMessage, p_payloadField, v_mandatoryHeaders, p_headerFields);
                
            } // End of function f_buildGnSecuredDenm
            
            /**
            * @desc This function build and sign the SecureMessage part covered by the signature process
            * @param p_securedMessage       The signed  SecureMessage part
            * @param p_payloadField         Payloads to be included in the message
            * @param p_signerInfoType       Add digest or AT certificate or certificate chain
            * @param p_threeDLocation       The 3D location
            * @param p_headerFields         HeaderFields to be inserted in the message
            * @param p_certificateName      The certificate identifier to be used. Default: TA_CERT_A
            * @param p_addMissingHeaders    Whether to add mandatory headers not present in p_headerFields
            * @return true on success, false otherwise
            */
            function f_buildGnSecuredOtherMessage(
                                                  out template (value) SecuredMessage p_securedMessage,
                                                  in template (value) SecPayload p_payloadField,
                                                  in template (omit) SignerInfoType p_signerInfoType := e_certificate_digest_with_sha256,
                                                  in ThreeDLocation p_threeDLocation,
                                                  in template (omit) HeaderFields p_headerFields := omit,
                                                  in template (omit) charstring p_certificateName := omit,
                                                  in boolean p_addMissingHeaders := true
            ) runs on ItsSecurityBaseComponent return boolean {
                
                // Local variables
                var Certificate v_aaCertificate, v_atCertificate;
                var HeaderFields v_mandatoryHeaders := {};
                var HeaderField v_signerInfo;
                 
                // Load certificates if required
                if (f_prepareCertificates(p_certificateName, v_aaCertificate, v_atCertificate) == false) {
                    return false;
                }
                
                // Add additional headers if required
                if (p_addMissingHeaders == true) {
                    // Prepare mandatory headers
                    if (valueof(p_signerInfoType) == e_certificate) { // Add the AT certificate
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_certificate(
                                    v_atCertificate
                        )));
                    }
                    if (valueof(p_signerInfoType) == e_certificate_chain) { // Add the AT certificate + AA Certificate
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_certificates(
                                    {
                                        v_aaCertificate,
                                        v_atCertificate
                                    }
                                )
                        ));
                    }
                    if (valueof(p_signerInfoType) == e_certificate_digest_with_sha256) { // Add the AT certificate digest
                        v_signerInfo := valueof(
                            m_header_field_signer_info(
                                m_signerInfo_digest(
                                    v_atCertificate.signer_info.signerInfo.digest
                        )));
                    }
                    v_mandatoryHeaders := {
                        v_signerInfo,
                        valueof(m_header_field_generation_time(1000 * f_getCurrentTime())), // In us
                        valueof(m_header_field_generation_location(p_threeDLocation))
                    }
                }
                
                // Build the secured message and return it
                return f_buildGnSecuredMessage(p_securedMessage, p_payloadField, v_mandatoryHeaders, p_headerFields);
            } // End of function f_buildGnSecuredOtherMessage
            
        } // End of group hostSignatureHelpers
        
        group deviceSignatureHelpers {
             
            /**
            * @desc Verify the signature of the provided certificate
            * @param p_certificateToBeVerified Certificate to be verified
            * @param p_publicKey               Public key to verify the certificate signature
            * @return true on success, false otherwise
            * @verdict
            */
            function f_verifyCertificateSignatureWithPublicKey(
                                                               in template (value) Certificate p_certificateToBeVerified,
                                                               in template (value) PublicKey   p_publicKey
            ) return boolean {
                // Local variables
                var octetstring toBeVerifiedData;
                var octetstring v_signature;
                var boolean v_result := false;
                var template (value) ToBeSignedCertificate v_toBeSignedCertificate;
                
                // Create Certificate payload to be verified
                v_toBeSignedCertificate := m_toBeSignedCertificate(p_certificateToBeVerified);
                toBeVerifiedData := bit2oct(encvalue(v_toBeSignedCertificate));
                
                // Build the signature
                v_signature :=
                    '0000'O &
                    valueof(p_certificateToBeVerified.signature_.signature_.ecdsa_signature.r.x) &
                    valueof(p_certificateToBeVerified.signature_.signature_.ecdsa_signature.s);
                
                // Verify the certificate
                v_result := f_verifyWithEcdsaNistp256WithSha256(
                    toBeVerifiedData,
                    v_signature,
                    valueof(p_publicKey.public_key.eccPoint.x),
                    valueof(p_publicKey.public_key.eccPoint.y.y)
                );
                
                return v_result;
            } // End of finction f_verifyCertificateSignatureWithPublicKey
            
            /**
            * @desc Verify the signature of the provided secured message
            * @param p_certificateToBeVerified Certificate to be verified
            * @param p_issuingCertificate      Issuing certificate
            * @return true on success, false otherwise
            * @verdict
            */
            function f_verifyCertificateSignatureWithIssuingCertificate(
                                                                        in template (value) Certificate p_certificateToBeVerified,
                                                                        in template (value) Certificate p_issuingCertificate
            ) return boolean {
                for (var integer v_counter := 0; v_counter < lengthof(p_issuingCertificate.subject_attributes); v_counter := v_counter + 1) {
                    if (valueof(p_issuingCertificate.subject_attributes[v_counter].type_) == e_verification_key) {
                        return f_verifyCertificateSignatureWithPublicKey(
                            p_certificateToBeVerified,
                            p_issuingCertificate.subject_attributes[v_counter].attribute.key);
                    }
                } // End of 'for' statement
                
                return false;
            } // End of function f_verifyCertificateSignatureWithIssuingCertificate
            
            /**
            * @desc Verify the signature of the provided secured message
            * @param p_securedMessage  The message to be verified
            * @param p_publicKey       The ECDSA public key to verify a signature
            * @param p_certificate     Certificate to be used to verify the message
            * @return true on success, false otherwise
            * @verdict
            */
            function f_verifyGnSecuredMessageSignatureWithPublicKey(
                                                                    in template (value) SecuredMessage p_securedMessage,
                                                                    in template (value) PublicKey p_publicKey
            ) return boolean {
                
                // Local variables
                var octetstring v_secPayload;
                var octetstring v_signedData;
                var Oct32 v_hash;
                var integer v_counter;
                var boolean v_result := false;
                var template (value) ToBeSignedSecuredMessage v_toBeSignedSecuredMessage;
                
                log(">>> f_verifyGnSecuredMessageSignatureWithPublicKey: ", p_securedMessage, p_publicKey);
                
                // Create SecuredMessage payload to be signed
                v_toBeSignedSecuredMessage := m_toBeSignedSecuredMessage(
                    p_securedMessage.header_fields,
                    p_securedMessage.payload_field,
                    e_signature
                );
                log("f_verifyGnSecuredMessageSignatureWithPublicKey: v_toBeSignedSecuredMessage=", v_toBeSignedSecuredMessage);
                
                v_secPayload := bit2oct(encvalue(v_toBeSignedSecuredMessage));
                log("f_verifyGnSecuredMessageSignatureWithPublicKey: v_secPayload=", v_secPayload);
                
                // Calculate the hash of the SecuredMessage payload to be signed
                v_hash := fx_hashWithSha256(v_secPayload);
                log("f_verifyGnSecuredMessageSignatureWithPublicKey: v_hash=", v_hash);
                
                // Verify payload
                for (v_counter := 0; v_counter < lengthof(p_securedMessage.trailer_fields); v_counter := v_counter + 1) {
                    var SecuredMessage v_securedMessage := valueof(p_securedMessage);
                    if (
                        (v_securedMessage.trailer_fields[v_counter].type_ == e_signature) and
                        (v_securedMessage.trailer_fields[v_counter].trailerField.signature_.algorithm == e_ecdsa_nistp256_with_sha256)
                    ) {
                        v_signedData :=
                        '0000'O &
                        v_securedMessage.trailer_fields[v_counter].trailerField.signature_.signature_.ecdsa_signature.r.x &
                        v_securedMessage.trailer_fields[v_counter].trailerField.signature_.signature_.ecdsa_signature.s;
                        log("f_verifyGnSecuredMessageSignatureWithPublicKey: v_signedData=", v_signedData);
                        v_result := f_verifyWithEcdsaNistp256WithSha256(
                            v_hash,
                            v_signedData,
                            valueof(p_publicKey.public_key.eccPoint.x),
                            valueof(p_publicKey.public_key.eccPoint.y.y)
                        );
                        break;
                    }
                } // End of 'for' statement
                
                log("f_verifyGnSecuredMessageSignatureWithPublicKey: v_result=", v_result);
                return v_result;
            } // End of function f_verifyCertificateSignatureWithPublicKey
            
            /**
            * @desc Verify the signature of the provided secured message
            * @param p_securedMessage
            * @param p_certificate     Certificate to be used to verify the message
            * @return true on success, false otherwise
            * @verdict
            */
            function f_verifyGnSecuredMessageSignatureWithCertificate(
                                                                      in template (value) SecuredMessage p_securedMessage,
                                                                      in template (value) Certificate p_certificate
            ) return boolean {
                
                for (var integer v_counter := 0; v_counter < lengthof(p_certificate.subject_attributes); v_counter := v_counter + 1) {
                    var SubjectAttribute v_subjectAttribute := valueof(p_certificate.subject_attributes[v_counter]);
                    
                    log("f_verifyGnSecuredMessageSignatureWithCertificate: processing ", v_subjectAttribute);
                    if (v_subjectAttribute.type_ == e_verification_key) {
                        return f_verifyGnSecuredMessageSignatureWithPublicKey(
                            p_securedMessage,
                            p_certificate.subject_attributes[v_counter].attribute.key);
                    }
                } // End of 'for' statement
                
                return false;
            } // End of function f_verifyGnSecuredOtherMessageWithDeviceCertificate
            
        } // End of group deviceSignatureHelpers
        
        group messageGetters {
            
            /**
            * @desc    return SecuredMessage header field of given type or null if none
            * @param   p_msg the SecuredMessage
            * @param   p_type header field type
            * @return  HeaderField of given type if any or null
            */
            function f_getMsgHeaderField(
                                         in  SecuredMessage p_securedMessage,
                                         in  HeaderFieldType p_headerFieldType,
                                         out HeaderField p_return
            ) return boolean {
                var integer v_length := lengthof(p_securedMessage.header_fields);
                
                for (var integer i := 0; i < v_length; i := i + 1) {
                    if (p_securedMessage.header_fields[i].type_ == p_headerFieldType) {
                        p_return := p_securedMessage.header_fields[i];
                        return true;
                    }
                }
                
                log("f_getMsgHeaderField: return false");
                return false;
            }
            
            /**
            * @desc    return SignerInfo SecuredMessage field
            */
            function f_getMsgSignerInfo (
                                         in SecuredMessage p_securedMessage,
                                         out SignerInfo p_signerInfo
            ) return boolean {
                var HeaderField v_hf;
                
                if (f_getMsgHeaderField(p_securedMessage, e_signer_info, v_hf) == true) {
                    if (isbound(v_hf.headerField.signer)) {
                        p_signerInfo := v_hf.headerField.signer;
                        return true;
                    }
                }
                
                log("f_getMsgSignerInfo: return false");
                return false;
            }
            
        }// End of group messageGetters
        
        group certificateGetters {
            
            /**
            * @desc Set the generation location as defined in Draft ETSI TS 103 097 V1.1.14 Clause 7.2 Security profile for DENMs
            * @param p_latitude    The latitude value of the ITS-S position
            * @param p_longitude   The longitude value of the ITS-S position
            * @param p_elevation   The elevation value of the ITS-S position
            * @verdict Unchanged
            */
            function f_setGenerationLocation(
                                             in WGSLatitude p_latitude,
                                             in WGSLongitude p_longitude,
                                             in Oct2 p_elevation := '0000'O
            ) runs on ItsSecurityBaseComponent {
                vc_location := {
                    p_latitude,
                    p_longitude,
                    p_elevation
                }
            } // End of function f_setGenerationLocation
            
            /**
            * @desc    Load in memory cache the certificates available
            * @param   p_configId      A configuration identifier
            * @remark  This method SHALL be call before any usage of certificates
            * @return  true on success, false otherwise
            */
            function f_loadCertificates(
                                        in charstring p_configId
            ) runs on ItsSecurityBaseComponent return boolean {
                var boolean v_result;
                
                // Setup certificates memory cache
                if (fx_loadCertificates(PX_ROOT_PATH_FOR_SECURITY, p_configId) == true) {
                    // Setup security component variables
                    f_readCertificate(cc_taCertA & ".AA_CERT", vc_aaCertificate);
                    f_readCertificate(cc_taCertA & ".AT_CERT", vc_atCertificate);
                    f_readPrivateKeys(cc_taCertA & ".PRIVATE_KEYS", vc_signingPrivateKey, vc_encryptPrivateKey);
                    
                    return true;
                }
                
                log("f_loadCertificates: Failed to access ", p_configId);
                return false;
            } // End of function f_loadCertificates
            
            /**
            * @desc    Unload from memory cache the certificates available
            * @return  true on success, false otherwise
            */
            function f_unloadCertificates() runs on ItsSecurityBaseComponent return boolean {
                // Reset security component variables
                vc_signingPrivateKey := '0000000000000000000000000000000000000000000000000000000000000000'O;
                vc_encryptPrivateKey := '0000000000000000000000000000000000000000000000000000000000000000'O;
                // Clear certificates memory cache
                return fx_unloadCertificates();
            } // End of function f_unloadCertificates
            
            /**
            * @desc    Read the specified certificate
            * @param   p_certificateId the certificate identifier
            * @param   p_certificate   the expected certificate
            * @return  true on success, false otherwise
            */
            function f_readCertificate(
                                       in charstring p_certificateId,
                                       out Certificate p_certificate
            ) runs on ItsSecurityBaseComponent return boolean {
                var octetstring v_certificate;
                
                if (fx_readCertificate(p_certificateId, v_certificate) == true) {
                    var bitstring v_oct2bit;
                    var integer v_result;
                    
                    v_oct2bit := oct2bit(v_certificate);
                    v_result := decvalue(v_oct2bit, p_certificate);
                    if (v_result == 0) {
                        return true;
                    }
                }
                
                log("f_readCertificate: Failed to retrieve ", p_certificateId);
                return false;
            } // End of function f_readCertificate
            
            /**
            * @desc    Read the private keys for the specified certificate
            * @param   p_keysId            the keys identifier
            * @param   p_signingPrivateKey the signing private key
            * @param   p_encryptPrivateKey the encrypt private key
            * @return  true on success, false otherwise
            */
            function f_readPrivateKeys(
                                       in charstring p_keysId,
                                       out Oct32 p_signingPrivateKey,
                                       out Oct32 p_encryptPrivateKey
            ) runs on ItsSecurityBaseComponent return boolean {
                return fx_readPrivateKeys(p_keysId, p_signingPrivateKey, p_encryptPrivateKey);
            } // End of function f_readPrivateKeys
            
            function f_getCertificateValidityRestriction(
                                                         in template (value) Certificate p_cert,
                                                         in ValidityRestrictionType p_type,
                                                         out ValidityRestriction p_return
            ) return boolean {
                
                for (var integer i := 0; i < lengthof(p_cert.validity_restrictions); i := i + 1) {
                    if (valueof(p_cert).validity_restrictions[i].type_ == p_type) {
                        p_return := valueof(p_cert).validity_restrictions[i];
                        return true;
                    }
                } // End of 'for' statement
                
                log("f_getCertificateValidityRestriction: Failed to retrieve ", p_type);
                return false;
            } // End of function f_getCertificateValidityRestriction
            
            function f_getCertificateSignerInfo(
                                                in template (value) Certificate p_cert,
                                                out SignerInfo p_si
            ) return boolean {
                if (isbound(valueof(p_cert.signer_info))) {
                    p_si := valueof(p_cert.signer_info);
                    return true;
                }
                return false;
            }
            
            function f_getCertificateSubjectAttribute(
                                                      in template (value) Certificate p_cert,
                                                      in SubjectAttributeType p_type,
                                                      out SubjectAttribute p_return
            ) return boolean {
                for (var integer i := 0; i < lengthof(p_cert.subject_attributes); i := i + 1) {
                    if (valueof(p_cert).subject_attributes[i].type_ == p_type) {
                        p_return := valueof(p_cert).subject_attributes[i];
                        return true;
                    }
                }
                
                log("f_getCertificateSubjectAttribute: Failed to retrieve ", p_type);
                return false;
            }
            
        }// End of group certificateGetters
        
    } // End of group helpersFunctions

    group externalFunctions {
        
        group signing {
            
            /**
            * @desc    Produces a 256-bit (32-byte) hash value
            * @param   p_toBeHashedData Data to be used to calculate the hash value
            * @return  The hash value
            */
            external function fx_hashWithSha256(in octetstring p_toBeHashedData) return Oct32;
            
            /**
            * @desc    Produces a Elliptic Curve Digital Signature Algorithm (ECDSA) signaturee
            * @param   p_toBeSignedSecuredMessage    The data to be signed
            * @param   p_privateKey        The private key
            * @return  The signature value
            */
            external function fx_signWithEcdsaNistp256WithSha256(in octetstring p_toBeSignedSecuredMessage, in octetstring/*UInt64*/ p_privateKey) return octetstring;
            
            /**
            * @desc    Verify the signature of the specified data
            * @param   p_toBeVerifiedData          The data to be verified
            * @param   p_signature                 The signature
            * @param   p_ecdsaNistp256PublicKeyX   The public key (x coordinate)
            * @param   p_ecdsaNistp256PublicKeyY   The public key (y coordinate)
            * @return  true on success, false otherwise
            */
            external function fx_verifyWithEcdsaNistp256WithSha256(in octetstring p_toBeVerifiedData, in octetstring p_signature, in octetstring p_ecdsaNistp256PublicKeyX, in octetstring p_ecdsaNistp256PublicKeyY) return boolean;
            
            /**
            * @desc    Produce a new public/private key pair based on Elliptic Curve Digital Signature Algorithm (ECDSA) algorithm.
            *          This function should not be used by the ATS
            * @param   p_privateKey    The new private key value
            * @param   p_publicKeyX    The new public key value (x coordinate)
            * @param   p_publicKeyX    The new public key value (y coordinate)
            * @return  true on success, false otherwise
            */
            external function fx_generateKeyPair(out octetstring/*UInt64*/ p_privateKey, out octetstring p_publicKeyX, out octetstring p_publicKeyY) return boolean;
            
        } // End of group signing
        
        group encryption {
            
        } // End of group encryption
        
        group certificatesLoader {
            
            /**
            * @desc    Load in memory cache the certificates available in the specified directory
            * @param   p_rootDirectory Root directory to access to the certificates identified by the certificate ID
            * @param   p_configId      A configuration identifier
            * @remark  This method SHALL be call before any usage of certificates
            * @return  true on success, false otherwise
            */
            external function fx_loadCertificates(in charstring p_rootDirectory, in charstring p_configId) return boolean;
            
            /**
            * @desc    Unload from memory cache the certificates
            * @return  true on success, false otherwise
            */
            external function fx_unloadCertificates() return boolean;
            
            /**
            * @desc    Read the specified certificate
            * @param   p_certificateId the certificate identifier
            * @param   p_certificate   the expected certificate
            * @return  true on success, false otherwise
            */
            external function fx_readCertificate(in charstring p_certificateId, out octetstring p_certificate) return boolean;
            
            /**
            * @desc    Read the private keys for the specified certificate
            * @param   p_keysId            the keys identifier
            * @param   p_signingPrivateKey the signing private key
            * @param   p_encryptPrivateKey the encrypt private key
            * @return  true on success, false otherwise
            */
            external function fx_readPrivateKeys(in charstring p_keysId, out Oct32 p_signingPrivateKey, out Oct32 p_encryptPrivateKey) return boolean;
            
        } // End of group certificatesLoader
        
        group geodesic {
            
            /**
            * @desc    Check that given polygon doesn't have neither self-intersections nor holes.
            * @param   p_region   Polygonal Region
            * @return  true on success, false otherwise
            * @verdict Unchanged
            */
            external function fx_isValidPolygonalRegion(in PolygonalRegion p_region) return boolean;
            
            /**
            * @desc Check if a polygonal regin is inside another one
            * @param p_parent  The main polygonal region
            * @param p_region  The polygonal region to be included
            * @return true on success, false otherwise
            * @verdict Unchanged
            */
            external function fx_isPolygonalRegionInside(in PolygonalRegion p_parent, in PolygonalRegion p_region) return boolean;
            
            /**
            * @desc Check that the location is inside a circular region
            * @param p_region      The circular region to consider
            * @param p_location    The device location
            * @return true on success, false otherwise
            * @verdict Unchanged
            */
            external function fx_isLocationInsideCircularRegion(in CircularRegion p_region, in ThreeDLocation p_location) return boolean;
            
            /**
            * @desc Check that the location is inside a rectangular region
            * @param p_region      The rectangular region to consider
            * @param p_location    The device location
            * @return true on success, false otherwise
            * @verdict Unchanged
            */
            external function fx_isLocationInsideRectangularRegion(in RectangularRegions p_region, in ThreeDLocation p_location) return boolean;
            
            /**
            * @desc Check that the location is inside a polygonal region
            * @param p_region      The polygonal region to consider
            * @param p_location    The device location