I am encrypting a message using  Crypto.decryptWithManagedIV() method. Let my key be:   Wr/wa0vAe9RNmiMr 
This is the encryption and decryption process:
 

Blob cryptoKeyBlob = Blob.valueOf('Wr/wa0vAe9RNmiMr');
Blob msgBlob = Blob.valueOf('my message to be encrypted');
Blob encryptedMsgBlob = Crypto.encryptWithManagedIV('AES128', cryptoKeyBlob, msgBlob);
String encryptedMsgString = EncodingUtil.base64Encode(encryptedMsgBlob);

 

Blob keyBlob = Blob.valueOf('Wr/wa0vAe9RNmiMr');
Blob encryptedMsgBlob = EncodingUtil.base64Decode(encryptedMsgString);
Blob decryptedMsgBlob = Crypto.decryptWithManagedIV('AES128', keyBlob, encryptedMsgBlob);
String decryptedMsgString = decryptedMsgBlob.toString();

The encryption code lives in a different class and so does the decryption code.

Here is the issue. When I directly use the key in the code it works. But since referring a key in the code is not a good process I am using a custom setting to store it. But when the key is read from the custom setting and used in the code it throws an error saying: 
Input length must be multiple of 16 when decrypting with padded cipher

I debugged the code and it seems the key is read as it is and there is no change. I do not understand what is going wrong. Any help will be much appreciated.

I am encrypting a message using  Crypto.decryptWithManagedIV() method. Let my key be:   Wr/wa0vAe9RNmiMr 
This is the encryption and decryption process:
 

Blob cryptoKeyBlob = Blob.valueOf('Wr/wa0vAe9RNmiMr');
Blob msgBlob = Blob.valueOf('my message to be encrypted');
Blob encryptedMsgBlob = Crypto.encryptWithManagedIV('AES128', cryptoKeyBlob, msgBlob);
String encryptedMsgString = EncodingUtil.base64Encode(encryptedMsgBlob);

 

Blob keyBlob = Blob.valueOf('Wr/wa0vAe9RNmiMr');
Blob encryptedMsgBlob = EncodingUtil.base64Decode(encryptedMsgString);
Blob decryptedMsgBlob = Crypto.decryptWithManagedIV('AES128', keyBlob, encryptedMsgBlob);
String decryptedMsgString = decryptedMsgBlob.toString();

The encryption code lives in a different class and so does the decryption code.

Here is the issue. When I directly use the key in the code it works. But since referring a key in the code is not a good process I am using a custom setting to store it. But when the key is read from the custom setting and used in the code it throws an error saying: 
Input length must be multiple of 16 when decrypting with padded cipher

I debugged the code and it seems the key is read as it is and there is no change. I do not understand what is going wrong. Any help will be much appreciated.