PKCS8 format scheme not available.

[chetan15aggarwal]

Hi,

I am trying to implement a specific test case with this lib. I want to generate PKCS8 format keypair. As of now I am unable to figure out how I can achieve.

Other details - 2048 bit, SHA256

Trying on XCode 11.

[Abdmin01]

I'm trying to do this too. Did you solve it?

[chetan15aggarwal]

Yes, I have added PKCS8 Hearder explicitly. Below is its implementation and source code.

` internal func getPublicKeyBase64String() -> String { guard let lpublicKey = publicKey else { return "" } do { let data = try lpublicKey.data() let pkcs8Key = addPKCS8Header(data) return pkcs8Key.base64EncodedString() } catch { print(error.localizedDescription) } return "" }

private func addPKCS8Header(_ derKey: Data) -> Data {
    var result = Data()

    let encodingLength: Int = encodedOctets(derKey.count + 1).count
    let OID: [UInt8] = [0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
                        0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05, 0x00]

    var builder: [UInt8] = []

    // ASN.1 SEQUENCE
    builder.append(0x30)

    // Overall size, made of OID + bitstring encoding + actual key
    let size = OID.count + 2 + encodingLength + derKey.count
    let encodedSize = encodedOctets(size)
    builder.append(contentsOf: encodedSize)
    result.append(builder, count: builder.count)
    result.append(OID, count: OID.count)
    builder.removeAll(keepingCapacity: false)

    builder.append(0x03)
    builder.append(contentsOf: encodedOctets(derKey.count + 1))
    builder.append(0x00)
    result.append(builder, count: builder.count)

    // Actual key bytes
    result.append(derKey)

    return result
}

private func encodedOctets(_ int: Int) -> [UInt8] {
    // Short form
    if int < 128 {
        return [UInt8(int)]
    }

    // Long form
    let i = (int / 256) + 1
    var len = int
    var result: [UInt8] = [UInt8(i + 0x80)]

    for _ in 0..<i {
        result.insert(UInt8(len & 0xFF), at: 1)
        len = len >> 8
    }

    return result
}`

[feixue299]

Currently, it appears that the library Padding, or SecPadding, does not have the PKCS8 format.