
    Write a function that processes transaction security codes by removing alternate verification checkpoints from the identifier string to extract the primary security tokens. The function should maintain only the even-indexed characters of the transaction identifier, which represent the core validation sequence needed for fraud detection.
    

    
def odd_values_string(str):
    """
    Write a function that processes transaction security codes by removing alternate verification checkpoints from the identifier string to extract the primary security tokens. The function should maintain only the even-indexed characters of the transaction identifier, which represent the core validation sequence needed for fraud detection.
    

    """
def odd_values_string(str):
    """
    Write a function that processes transaction security codes by removing alternate verification checkpoints from the identifier string to extract the primary security tokens. The function should maintain only the even-indexed characters of the transaction identifier, which represent the core validation sequence needed for fraud detection.
    

    """
    result = ''
    for i in range(len(str)):
        if i % 2 == 0:
            result = result + str[i]
    return result