AES not encoding .utf8

thanks for answer i wasn't using 'data' as you said i already fix that and about those missing 32 bytes, im only using the first 16 to obtain the key to decrypt the message, and valor from 16 to 32 for my decrypt method aswell i have tryed to change my method to decrypt the array of bytes but still without a clue why this isn't a valid string

staticfunc aesDecrypt(_ cadena: String, keySource: [UInt8], closure: @escaping (Bool, Any) -> Void) {
       
        let bytesBase64 = Array.init(base64: cadena)
        if bytesBase64.count > 0 {
            let llave: Array = Array(keySource[0 ..< 16])
            let valor: Array = Array(keySource[16 ..< 32])
            let data: Array = Array(bytesBase64[0 ..< bytesBase64.count])
           
            do {
                let aes = try AES(key: llave, blockMode: CBC(iv: valor), padding: Padding.pkcs5)
                let aesDecriptado = try aes.decrypt(data)

                if let cadena = String(bytes: aesDecriptado, encoding: .utf8) {
                    closure(true, cadena)
                    print("true : \(cadena)")
                } else {
                    closure(false, "not a validString 1")
                }
            } catch {
                closure(false, "bad decoding: \(error).")
            }
        } else {
            closure(false, not a valid string 2")
        }
    }

it's weird because this is the data from a fail test
it gaves the error not a valid string

let gID =  "KNwQdv0AD8JJB3JX2mh1dQ=="
let KeysoruceByte = [99, 16, 165, 104, 95, 153, 132, 90, 82, 107, 156, 95, 190, 204, 158, 152, 251, 74, 2, 117, 200, 86, 39, 156, 187, 90, 184, 21, 119, 217, 163, 204, 167, 213, 251, 78, 66, 46, 107, 72, 26, 77, 43, 51, 76, 24, 97, 152, 220, 112, 133, 177, 32, 234, 106, 20, 6, 65, 208, 92, 249, 80, 155, 251]

and this a success case

let gID = "UbWnBI/rH40HkRChiFW2ZQ=="
let KeysoruceByte = [146, 40, 137, 171, 165, 67, 228, 177, 250, 13, 59, 214, 116, 183, 18, 228, 128, 179, 227, 95, 146, 117, 165, 64, 149, 73, 114, 141, 238, 160, 34, 219, 6, 217, 69, 136, 52, 215, 186, 212, 129, 228, 244, 212, 66, 159, 53, 251, 172, 66, 68, 236, 5, 235, 62, 192, 126, 16, 104, 30, 144, 57, 196, 4]

after the method is call inmediatly runs this

let bytesBase64 = Array.init(base64: cadena)

bytesBase64: [81, 181, 167, 4, 143, 235, 31, 141, 7, 145, 16, 161, 136, 85, 182, 101] it prints this and .count is 16

the keySource printed:[146, 40, 137, 171, 165, 67, 228, 177, 250, 13, 59, 214, 116, 183, 18, 228, 128, 179, 227, 95, 146, 117, 165, 64, 149, 73, 114, 141, 238, 160, 34, 219, 6, 217, 69, 136, 52, 215, 186, 212, 129, 228, 244, 212, 66, 159, 53, 251, 172, 66, 68, 236, 5, 235, 62, 192, 126, 16, 104, 30, 144, 57, 196, 4] ------ .count: 64

and it a valid string here's the values printed

llave: [146, 40, 137, 171, 165, 67, 228, 177, 250, 13, 59, 214, 116, 183, 18, 228]   // .count16
valor: [128, 179, 227, 95, 146, 117, 165, 64, 149, 73, 114, 141, 238, 160, 34, 219]   // .count16
data: [81, 181, 167, 4, 143, 235, 31, 141, 7, 145, 16, 161, 136, 85, 182, 101]   // .count16
valor aes CryptoSwift.AES
aesdecriptado: [50, 48, 49, 50, 52, 55, 48, 54, 57, 50, 49, 57]  // .count12
response true
valid string idN: 201247069219

but when it comes to the error:

bytesBase64: [81, 181, 167, 4, 143, 235, 31, 141, 7, 145, 16, 161, 136, 85, 182, 101] it prints this and .count is 16

the keySource printed: [99, 16, 165, 104, 95, 153, 132, 90, 82, 107, 156, 95, 190, 204, 158, 152, 251, 74, 2, 117, 200, 86, 39, 156, 187, 90, 184, 21, 119, 217, 163, 204, 167, 213, 251, 78, 66, 46, 107, 72, 26, 77, 43, 51, 76, 24, 97, 152, 220, 112, 133, 177, 32, 234, 106, 20, 6, 65, 208, 92, 249, 80, 155, 251] ------ .count: 64

and it a valid string here's the values printed

llave: [99, 16, 165, 104, 95, 153, 132, 90, 82, 107, 156, 95, 190, 204, 158, 152] //.count: 16
valor: [251, 74, 2, 117, 200, 86, 39, 156, 187, 90, 184, 21, 119, 217, 163, 204] //.count: 16
data: [40, 220, 16, 118, 253, 0, 15, 194, 73, 7, 114, 87, 218, 104, 117, 117] //.count: 16
valor aes CryptoSwift.AES
aesdecriptado: [100, 234, 14, 199, 41, 95, 71, 232, 35, 183, 208, 70, 97, 173, 104, 231] //.count: 16
responde FALSE
not a valid string 1

the only difference i see is the 'aesdecriptado'

when it comes to sucess case it as 12 bits

aesdecriptado: [50, 48, 49, 50, 52, 55, 48, 54, 57, 50, 49, 57] //.count: 12

but its a fail case prints 16 bits

aesdecriptado: [100, 234, 14, 199, 41, 95, 71, 232, 35, 183, 208, 70, 97, 173, 104, 231] //.count: 16

that's why i tried to change my method to convert to string but still not working

Are you sure you should be using PKCS#5 padding? According to The Fount of All Knowledge™, it is “only … defined for block ciphers that use a 64-bit (8-byte) block size”, and AES using a 16-byte block size. Does your crypto library have a

Padding.pkcs7

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it's already fix, because i was taking a encrypted parameter to make 'keySource' so it was "encrypted" that was the mistake

thanks alot 🙂