CmValidateSignature

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CmValidateSignature

Contents

Description

CmValidateSignature validates a passed signature using the passed public key and the ECDSA algorithm.

Syntax

int CMAPIENTRY CmValidateSignature(CMAUTHENTICATE *pcmAuth, CMBYTE *pbSignature, CMUINT cbSignature, CMBYTE *pbPubKey, CMUINT cbPubKey);

Parameter

pcmAuth contains the specification of the validation process (see structure CMAUTHENTICATE).

Structure CMAUTHENTICATE

CMAUTHENTICATE contains all information needed for an authentication process.

Syntax

typedef struct __CMAUTHENTICATE {

CMULONG mflCtrl;
CMULONG mulKeyExtType;
CMULONG mulFirmCode;
CMULONG mulProductCode;
CMULONG mulEncryptionCodeOptions;
CMULONG mulFeatureCode;
CMBOXINFO mcmBoxInfo;
CMBYTE mabDigest[CM_DIGEST_LEN];

} CMAUTHENTICATE;

Parameter

mflCtrl contains one of the following commands:

CM_AUTH_HIDDENDATA specifies that the signature calculation is done with a Hidden Data field.

CM_AUTH_SECRETDATA specifies that the signature calculation is done with a Secret Data field.

CM_AUTH_SERIALKEY specifies that the signature calculation is done with the Serial Key.

CM_AUTH_BOXKEY specifies that the signature calculation is done with the Box Key.

CM_AUTH_KSMASK can be used to mask bits used for specifying the key source.

CM_AUTH_AMMASK can be used to mask bits used for specifying the authentication mode.

This commands can be or'ed with one of the following flags:

CM_AUTH_DIRECT uses the specified digest directly as input of the ECDSA algorithm.

CM_AUTH_EXTENDED defines that the specified Encryption Code Options and Feature Code influence the use of the Product Item and influences the signature calculation.

CM_AUTH_EXTENDED2 improves the definition that the specified Encryption Code Options and Feature Code influence the use of the Product Item and influences the signature calculation .
The flag has been introduced with CodeMeter Version 5.10.
Plese note that using CM_AUTH_EXTENDED2 requires at least hardware version 2.03.

CM_AUTH_SERIAL defines that the specified Encryption Code Options influence the use of the Product Item and influences together with the Serial Number of the CmContainer the signature calculation.

mulKeyExtType contains the extended type of the Hidden Data or Secret Data PIO, if in mflCtrl CM_AUTH_HIDDENDATA or CM_AUTH_SECRETDATA is specified. Otherwise this member must be set to 0.

mulFirmCode contains the Firm Code used for the authentication process.

mulProductCode contains the Product Code used for the authentication process.

mulEncryptionCodeOptions contains the Encryption Code Options, this are the higher 32 bits of the Encryption Code. This value is only used, if mflCtrl has set the CM_AUTH_EXTENDED,CM_AUTH_EXTENDED2 or CM_AUTH_SERIAL option. Otherwise it must be set to 0.

mulFeatureCode contains the used Feature Code, which must match the used Feature Map. This value is only used, if mflCtrl has set the CM_AUTH_EXTENDED, CM_AUTH_EXTENDED2 option. Otherwise it must be set to 0.

mcmBoxInfo contains the CmContainer information used for the authentication process.

mabDigest contains the 32-byte res. 256-bit digest which is signed.

pbSignature contains the buffer for the signature to validate.

cbSignature contains the length of the pbSignature buffer.

pbPubKey contains the buffer for the public key needed for validation.

cbPubKey contains the length of the pbPubKey buffer.

Return

The hash value used for the signature must always be set into pcmAuth->mabDigest. The value pcmAuth->mflCtrl is set to one of the following values: CM_AUTH_DIRECT, CM_AUTH_EXTENDED,CM_AUTH_EXTENDED2, CM_AUTH_SERIAL. Depending on this value the following values must be set accordingly:

•CM_AUTH_DIRECT: All other values are ignored and can be set to 0.

•CM_AUTH_EXTENDED, CM_AUTH_EXTENDED2: pcmAuth->mulEncryptionCodeOptions and pcmAuth->mulFeatureCode have to have the same value as for CmValidateSignature. pcmAuth->mulFirmCode and pcmAuth->mulProductCode have to match the values used for CmAccess2 performed for CmCalculateSignature.

•CM_AUTH_SERIAL: pcmAuth->mulEncryptionCodeOptions has to have the same value as for CmCalculateSignature. pcmAuth->mcmBoxInfo.musBoxMask and pcmAuth->mcmBoxInfo.mulSerialNumber have to be set to identify the signing box. pcmAuth->mulFirmCode and pcmAuth->mulProductCode have to match the values used for CmAccess2 performed for CmValidateSignature.

performed for CmValidateSignature.

•Serial: Auth->EncryptionCodeOptions has to have the same value as for CmCalculateSignature: Auth->BoxInfo.BoxMask and Auth->BoxInfo.SerialNumber have to be set to identify the signing box. Auth->FirmCode and Auth->ProductCode have to match the values used for CmAccess2 performed for CmValidateSignature.