(Swift 3,4,5...) Generate RSA Key and Sign a String

See more RSA Examples

Demonstrates how to generate a new RSA public/private key pair and use it to generate a signature for a string. The (binary) digital signature is returned as a hexidecimalized string.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let rsa = CkoRsa()!

    // Generate a 2048-bit RSA key.
    var success: Bool = rsa.generateKey(2048)

    // To return the signature in hex.
    rsa.encodingMode = "hex"

    var strData: String? = "This is the string to be signed."

    // Sign the SHA256 hash of the string.
    var hexSig: String? = rsa.signStringENC(strData, hashAlg: "sha256")

    print("\(hexSig!)")
    print("\(rsa.lastErrorText!)")

    // Now verify the signature:
    success = rsa.verifyStringENC(strData, hashAlg: "sha256", sig: hexSig)
    if success == true {
        print("Signature verified!")
    }
    else {
        print("\(rsa.lastErrorText!)")
    }

    // Try it with an invalid signature:
    success = rsa.verifyStringENC(strData, hashAlg: "sha256", sig: "not a valid sig")
    if success == true {
        print("Signature verified!")
    }
    else {
        print("\(rsa.lastErrorText!)")
    }

    // Try it with invalid data:
    success = rsa.verifyStringENC("Not the original data", hashAlg: "sha256", sig: hexSig)
    if success == true {
        print("Signature verified!")
    }
    else {
        print("\(rsa.lastErrorText!)")
    }

    // Try it with the wrong hash algorithm:
    success = rsa.verifyStringENC(strData, hashAlg: "sha-1", sig: hexSig)
    if success == true {
        print("Signature verified!")
    }
    else {
        print("\(rsa.lastErrorText!)")
    }


}