I'm createing RSA public and private key pairs like below.var statusCode: OSStatus var publicKey: SecKey? var privateKey: SecKey? let publicKeyAttribute: [NSObject : NSObject] = [kSecAttrIsPermanent: true as NSObject, kSecAttrApplicationTag: "com.anu.keys.apppublic".data(using: String.Encoding.utf8)! as NSObject] let privateKeyAtrribute: [NSObject: NSObject] = [kSecAttrIsPermanent: true as NSObject, kSecAttrApplicationTag: "com.anu.keys.appprivate".data(using: String.Encoding.utf8)! as NSObject] var keyPairAttr = [NSObject: Any]() keyPairAttr[kSecAttrType] = kSecAttrKeyTypeRSA keyPairAttr[kSecAttrKeySizeInBits] = 2048 keyPairAttr[kSecReturnData] = true keyPairAttr[kSecPublicKeyAttrs] = publicKeyAttribute keyPairAttr[kSecPrivateKeyAttrs] = privateKeyAtrribute statusCode = SecKeyGeneratePair(keyPairAttr as CFDictionary, &publicKey, &privateKey)This generates two keys properly and keys are like below,public key<SecKeyRef algorithm id: 1, key type: RSAPublicKey, version: 4, block size: 2048 bits, exponent: {hex: 10001, decimal: 65537}, modulus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addr: 0x608000420e80>private key<SecKeyRef algorithm id: 1, key type: RSAPrivateKey, version: 4, block size: 2048 bits, addr: 0x60000003b960>But I cannot use those keys with any other platforms such as .net or android. it says invalid key format. in android the key can see like below,***** key-----BEGIN RSA PUBLIC KEY----- MIIBCgKCAQEA0bipoOhkkvPxcsyOzcqsIUeVe0+iwe8W7N4EbHZMgujRERu1TPpy UcCO0uuKmm1TU09Kl40rRvDbtgB1YcGV3FPnNp3sOyFVsdyZ5bzxZtyyLrSWtj/n bLnGwaG9xJSwd2R/pTQLzOLV5KldwD2eUb3Z4Z4e9Z8II7eWgGaCLLqbrtEAa05N EqARckxrzJ1S3j+59h4AQovF72KI90/kRPryT2OGDiVlJ6CTjn2ZnTYcx65X6Rwf AeJKHZAGhw96j9tXyS+dJcXy4IBUTi3PXw0aEfhHQr/JsSHuMp/8mrhVJEokXb1C gKDZgJXujpGhCBdztHBAJxLBQMlODg7srwIDAQAB -----END RSA PUBLIC KEY-----Private key-----BEGIN RSA PRIVATE KEY----- MIIEowIBAAKCAQEAsfxMagVKY5++61Kot0esyhEOesqyQlZNvWbqMBcOoaOAb3pk LvwaGJ2YtD12u4yDEKcY5rpX7B/2t8GBHf+74NG47zAutf4Gf6qgQRUmIx2b7i4k WBt3KIifb/Zfs9KVJLhD4007bg1OtXA4kIhhXiuvhajDjDLOEthogF45CkJe+N67 JnH5hVW5CqBxPyRCrWCFbEHcXs5H515JV/Kz1+JVrB2/M03fW751wptO2GdGwsde ofqQzY+WUzqUihXigIjAVLFRemky3HpwuhzXUJn6A0ZD4tkk1JLstpSSJdBpH+L2 b9QlOitehxFgRsYmto+idpD1XrS9UyUtmpbTuwIDAQABAoIBAQCYvrAJcJ7lnmtn Ytm96LoF89tcT+Xpfk1bFR43xSHeYAXSJdQiamIu69joHbNuwuib+vsoz5Sy5L+D 9YHMb/MZvoIaa1w6/VUwbQr4r6C6FCgEoP65ymBZnd5OZL6/ASLTj3tbb6VoDe2V UkiI6TG+cnlAmJOxFsy5aZVNTQ9gmCMS0+AdpTbDsxTPg3y0EKFXeVRyKjq0lO9m p3G5yHkFjzWWY6s5XHx27gDTt8eXg/un72Qsz1rh5iUnAoxrga0Oco3Yk9DMvMwz a1I1Lo5fpB6FbTGX3k24heSnLDFEnlBvsBBg0g/n/qgwoZJ81MgG8Q4kAfeScuCI sYVnHEBpAoGBAOpnrKEkyhk1rXG4Md+z1/odhqx89mV7mF1ttW4IhFcwpJSMohsG r27Ic87whkpRxz2Mwj3B5WPGne4UkbvniH46n3jEW7ZIUF+ASVWkjMaGJWtOqSLC I19Snie9WvpREwaCVuvT2l4IeM1WL5gKotBwa3csZgGYH6gcyW5Ipbo/AoGBAMJh /+WXbohF4+A989q0jYjRRhKwUJAYeK8/AePrx8MnAXnRd09TiqeGn0Xig/RNZ0RE 96/TC1dTIBIHk5aDMy3vQhhYF0KbwcQWmCOnGo1qNTTaWTa3UitFMWf0hO0HuZtp RyD1YwhHP0W2tiK2GVjCreqIYASCpYKLq5Qq1K+FAoGARk2h8RLfqn/27UyZaMa/ 2DxS0BkKrZVMNXlaGQ5k4uGr+wHS/NgcddWZJk/tdwzf/Q3ilDM7YZmIdIemzfy7 a2CZw9bgyuMVeA85733S2xgQ0QZepBYmFcjptnGMf9chJaqh90krDVjtImjfDXLj MjEFilC+p2vA0uMPZwxS6HECgYAc5dLUQBoHmlRRTwSEvBjagToopxujAHBYpUZT qwbMpWzbvl89ZM8VLrdY/V7en+89P/+OnRJvjgUTiRrQ4npmVs59rgLvPRamXzGJ A1u4MFTuoZNnxgMqOaQprzlfv6lBSHpxlOl/HpByfcJAENBd2LtgRZv4r6+JY9hD M8bgvQKBgCDTSCLj5c1CYyuJMdrz9L5+xLFmrmL48djhK460ZcmcZ/gP808CyXx/ sDneow+JWt7Jb3p5zyUvvq1aDGNSsn4plB2rg7AqtoHcZYyFFZGI/K/b6JZna1yu FUYOfcanunabxY1wPQxuvR+AEuufBjB0aKg+qkLCCN1HYQtLs+N8 -----END RSA PRIVATE KEY-----why is this. why ios(Apple) cannot provide standard public/private keys that can use with rest APIs and with other platforms. I don't want to use any third party libraries. hope your help with this.