The term post-office box number is identified in base64 scheme by the sequence cG9zdC1vZmZpY2UgYm94IG51bWJlcg==, while the MD5 signature is equal to f57ac3680f348ee96fdceb793e141559. The ASCII encoding of post-office box number in hexadecimal notation is 706f73742d6f666669636520626f78206e756d626572.