DataFlex

ECDSA Sign Data and Verify Signature

See more ECC Examples

Demonstrates using the Elliptic Curve Digital Signature Algorithm to hash data and sign it. Also demonstrates how to verify the ECDSA signature. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoCrypt
    String sHash1
    String sHash2
    Variant vPrivKey
    Handle hoPrivKey
    Variant vPrng
    Handle hoPrng
    Handle hoEcdsa
    String sEcdsaSigBase64
    Variant vPubKey
    Handle hoPubKey
    Integer iResult
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

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

    // To create an ECDSA signature, the data first needs to be hashed.  Then the hash
    // is signed.

    // Use Chilkat Crypt2 to generate a hash for any of the following
    // hash algorithms: SHA256, SHA384, SHA512, SHA1, MD5, MD2, HAVAL, RIPEMD128/160/256/320

    Get Create (RefClass(cComChilkatCrypt2)) To hoCrypt
    If (Not(IsComObjectCreated(hoCrypt))) Begin
        Send CreateComObject of hoCrypt
    End
    Set ComHashAlgorithm Of hoCrypt To "SHA256"
    Set ComCharset Of hoCrypt To "utf-8"
    Set ComEncodingMode Of hoCrypt To "base64"

    // Hash a string.
    Get ComHashStringENC Of hoCrypt "The quick brown fox jumps over the lazy dog" To sHash1
    Showln "hash1 = " sHash1

    // Or hash a file..
    Get ComHashFileENC Of hoCrypt "qa_data/hamlet.xml" To sHash2
    Showln "hash2 = " sHash2

    // (The Crypt2 API provides many other ways to hash data..)

    // -----------------------------------------------------------
    // An ECDSA private key is used for signing.  The public key is for signature verification.
    // Load our ECC private key.
    // Our private key file contains this:

    // 	// -----BEGIN PRIVATE KEY-----
    // 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
    // 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
    // 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
    // 	-----END PRIVATE KEY-----

    Get Create (RefClass(cComChilkatPrivateKey)) To hoPrivKey
    If (Not(IsComObjectCreated(hoPrivKey))) Begin
        Send CreateComObject of hoPrivKey
    End
    Get ComLoadPemFile Of hoPrivKey "qa_data/ecc/secp256r1-key-pkcs8.pem" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoPrivKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // We'll need a PRNG source for random number generation.
    // Use Chilkat's PRNG (for the Fortuna PRNG algorithm).
    Get Create (RefClass(cComChilkatPrng)) To hoPrng
    If (Not(IsComObjectCreated(hoPrng))) Begin
        Send CreateComObject of hoPrng
    End

    // Sign the hash..
    Get Create (RefClass(cComChilkatEcc)) To hoEcdsa
    If (Not(IsComObjectCreated(hoEcdsa))) Begin
        Send CreateComObject of hoEcdsa
    End
    Get pvComObject of hoPrivKey to vPrivKey
    Get pvComObject of hoPrng to vPrng
    Get ComSignHashENC Of hoEcdsa sHash1 "base64" vPrivKey vPrng To sEcdsaSigBase64
    Get ComLastMethodSuccess Of hoEcdsa To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoEcdsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "ECDSA signature = " sEcdsaSigBase64

    // -----------------------------------------------------------
    // Now let's verify the signature using the public key.

    Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
    If (Not(IsComObjectCreated(hoPubKey))) Begin
        Send CreateComObject of hoPubKey
    End
    Get ComLoadFromFile Of hoPubKey "qa_data/ecc/secp256r1-pubkey.pem" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoPubKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get pvComObject of hoPubKey to vPubKey
    Get ComVerifyHashENC Of hoEcdsa sHash1 sEcdsaSigBase64 "base64" vPubKey To iResult
    If (iResult = 1) Begin
        Showln "Signature is valid."
        Procedure_Return
    End

    If (iResult = 0) Begin
        Showln "Signature is invalid."
        Procedure_Return
    End

    If (iResult < 0) Begin
        Get ComLastErrorText Of hoEcdsa To sTemp1
        Showln sTemp1
        Showln "The VerifyHashENC method call failed."
        Procedure_Return
    End



End_Procedure