Enter the key square below and select encryption or decryption. Enter the text to convert it.
Since we can only use 25 characters in the key square, there is a possibility to choose which letter to substitute by another letter (by default J is substituted by I) or to omit a letter.

The bifid cipher is one of the classical ciphers and was invented around 1901 by Felix Delastelle. Bifid is a combination of substitution and fractionation, this causes the original text to spread over the entire encrytion, which is more secure.