(PureBasic) Verify a .p7m and get Algorithm Information

Demonstrates how to verify a .p7m and then examine the algorithms used by the signature.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCrypt2.pb"
IncludeFile "CkJsonObject.pb"

Procedure ChilkatExample()

    ; This example requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    inFile.s = "qa_data/p7m/brainpoolP256r1.p7m"
    outFile.s = "qa_output/something.dat"

    ; Verify and extract the signed data.
    success.i = CkCrypt2::ckVerifyP7M(crypt,inFile,outFile)
    If success = 0
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkCrypt2::ckDispose(crypt)
        ProcedureReturn
    EndIf

    ; Examine details about the signature(s)
    json.i = CkCrypt2::ckLastJsonData(crypt)
    CkJsonObject::setCkEmitCompact(json, 0)
    Debug CkJsonObject::ckEmit(json)

    ; Sample output

    ; {
    ;   "pkcs7": {
    ;     "verify": {
    ;       "digestAlgorithms": [
    ;         "sha256"
    ;       ],
    ;       "signerInfo": [
    ;         {
    ;           "cert": {
    ;             "serialNumber": "FFFFE552B302FFFFFF1E34C3ACEB2FFFF",
    ;             "issuerCN": "The common name of the cert...",
    ;             "issuerDN": "",
    ;             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    ;             "digestAlgName": "SHA256"
    ;           },
    ;           "contentType": "1.2.840.113549.1.7.1",
    ;           "signingTime": "190409140500Z",
    ;           "messageDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
    ;           "signingAlgOid": "1.2.840.10045.4.3.2",
    ;           "signerDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
    ;           "authAttr": [
    ;             {
    ;               "oid": "1.2.840.113549.1.9.3",
    ;               "oidName": "contentType"
    ;             },
    ;             {
    ;               "oid": "1.2.840.113549.1.9.5",
    ;               "oidName": "signingTime"
    ;             },
    ;             {
    ;               "oid": "1.2.840.113549.1.9.52",
    ;               "oidName": "1.2.840.113549.1.9.52",
    ;               "der": "MBs ... AwI="
    ;             },
    ;             {
    ;               "oid": "1.2.840.113549.1.9.4",
    ;               "oidName": "messageDigest"
    ;             },
    ;             {
    ;               "oid": "1.2.840.113549.1.9.16.2.47",
    ;               "oidName": "signingCertificateV2",
    ;               "der": "MCYw .. 7PlQ=="
    ;             },
    ;             {
    ;               "oid": "1.2.840.113549.1.9.20",
    ;               "oidName": "1.2.840.113549.1.9.20"
    ;             }
    ;           ]
    ;         }
    ;       ]
    ;     }
    ;   }
    ; }

    ; Code for parsing the above JSON...
    i.i
    count_i.i
    strVal.s
    certSerialNumber.s
    certIssuerCN.s
    certIssuerDN.s
    certDigestAlgOid.s
    certDigestAlgName.s
    contentType.s
    signingTime.s
    messageDigest.s
    signingAlgOid.s
    signerDigest.s
    j.i
    count_j.i
    oid.s
    oidName.s
    der.s

    i = 0
    count_i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.digestAlgorithms")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        strVal = CkJsonObject::ckStringOf(json,"pkcs7.verify.digestAlgorithms[i]")
        i = i + 1
    Wend
    i = 0
    count_i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.signerInfo")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        certSerialNumber = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.serialNumber")
        certIssuerCN = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.issuerCN")
        certIssuerDN = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.issuerDN")
        certDigestAlgOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.digestAlgOid")
        certDigestAlgName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.digestAlgName")
        contentType = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].contentType")
        signingTime = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signingTime")
        messageDigest = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].messageDigest")
        signingAlgOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signingAlgOid")
        signerDigest = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signerDigest")
        j = 0
        count_j = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.signerInfo[i].authAttr")
        While j < count_j
            CkJsonObject::setCkJ(json, j)
            oid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr[j].oid")
            oidName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr[j].oidName")
            der = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr[j].der")
            j = j + 1
        Wend
        i = i + 1
    Wend

    CkJsonObject::ckDispose(json)

    Debug "Success!"


    CkCrypt2::ckDispose(crypt)


    ProcedureReturn
EndProcedure